License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 17:07:57 +03:00
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// SPDX-License-Identifier: GPL-2.0
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2017-02-23 02:45:39 +03:00
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/*
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* Manage cache of swap slots to be used for and returned from
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* swap.
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*
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* Copyright(c) 2016 Intel Corporation.
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*
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* Author: Tim Chen <tim.c.chen@linux.intel.com>
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*
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* We allocate the swap slots from the global pool and put
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* it into local per cpu caches. This has the advantage
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* of no needing to acquire the swap_info lock every time
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* we need a new slot.
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*
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* There is also opportunity to simply return the slot
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* to local caches without needing to acquire swap_info
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* lock. We do not reuse the returned slots directly but
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* move them back to the global pool in a batch. This
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* allows the slots to coaellesce and reduce fragmentation.
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*
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* The swap entry allocated is marked with SWAP_HAS_CACHE
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* flag in map_count that prevents it from being allocated
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* again from the global pool.
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*
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* The swap slots cache is protected by a mutex instead of
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* a spin lock as when we search for slots with scan_swap_map,
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* we can possibly sleep.
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*/
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#include <linux/swap_slots.h>
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#include <linux/cpu.h>
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#include <linux/cpumask.h>
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#include <linux/vmalloc.h>
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#include <linux/mutex.h>
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mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
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#include <linux/mm.h>
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2017-02-23 02:45:39 +03:00
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static DEFINE_PER_CPU(struct swap_slots_cache, swp_slots);
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static bool swap_slot_cache_active;
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2017-02-23 02:45:46 +03:00
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bool swap_slot_cache_enabled;
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2017-02-23 02:45:39 +03:00
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static bool swap_slot_cache_initialized;
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DEFINE_MUTEX(swap_slots_cache_mutex);
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/* Serialize swap slots cache enable/disable operations */
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DEFINE_MUTEX(swap_slots_cache_enable_mutex);
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static void __drain_swap_slots_cache(unsigned int type);
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static void deactivate_swap_slots_cache(void);
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static void reactivate_swap_slots_cache(void);
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#define use_swap_slot_cache (swap_slot_cache_active && \
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swap_slot_cache_enabled && swap_slot_cache_initialized)
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#define SLOTS_CACHE 0x1
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#define SLOTS_CACHE_RET 0x2
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static void deactivate_swap_slots_cache(void)
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{
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mutex_lock(&swap_slots_cache_mutex);
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swap_slot_cache_active = false;
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__drain_swap_slots_cache(SLOTS_CACHE|SLOTS_CACHE_RET);
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mutex_unlock(&swap_slots_cache_mutex);
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}
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static void reactivate_swap_slots_cache(void)
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{
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mutex_lock(&swap_slots_cache_mutex);
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swap_slot_cache_active = true;
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mutex_unlock(&swap_slots_cache_mutex);
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}
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/* Must not be called with cpu hot plug lock */
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void disable_swap_slots_cache_lock(void)
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{
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mutex_lock(&swap_slots_cache_enable_mutex);
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swap_slot_cache_enabled = false;
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if (swap_slot_cache_initialized) {
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/* serialize with cpu hotplug operations */
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get_online_cpus();
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__drain_swap_slots_cache(SLOTS_CACHE|SLOTS_CACHE_RET);
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put_online_cpus();
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}
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}
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static void __reenable_swap_slots_cache(void)
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{
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swap_slot_cache_enabled = has_usable_swap();
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}
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void reenable_swap_slots_cache_unlock(void)
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{
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__reenable_swap_slots_cache();
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mutex_unlock(&swap_slots_cache_enable_mutex);
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}
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static bool check_cache_active(void)
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{
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long pages;
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if (!swap_slot_cache_enabled || !swap_slot_cache_initialized)
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return false;
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pages = get_nr_swap_pages();
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if (!swap_slot_cache_active) {
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if (pages > num_online_cpus() *
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THRESHOLD_ACTIVATE_SWAP_SLOTS_CACHE)
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reactivate_swap_slots_cache();
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goto out;
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}
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/* if global pool of slot caches too low, deactivate cache */
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if (pages < num_online_cpus() * THRESHOLD_DEACTIVATE_SWAP_SLOTS_CACHE)
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deactivate_swap_slots_cache();
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out:
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return swap_slot_cache_active;
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}
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static int alloc_swap_slot_cache(unsigned int cpu)
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{
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struct swap_slots_cache *cache;
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swp_entry_t *slots, *slots_ret;
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/*
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* Do allocation outside swap_slots_cache_mutex
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mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
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* as kvzalloc could trigger reclaim and get_swap_page,
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2017-02-23 02:45:39 +03:00
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* which can lock swap_slots_cache_mutex.
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*/
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treewide: kvzalloc() -> kvcalloc()
The kvzalloc() function has a 2-factor argument form, kvcalloc(). This
patch replaces cases of:
kvzalloc(a * b, gfp)
with:
kvcalloc(a * b, gfp)
as well as handling cases of:
kvzalloc(a * b * c, gfp)
with:
kvzalloc(array3_size(a, b, c), gfp)
as it's slightly less ugly than:
kvcalloc(array_size(a, b), c, gfp)
This does, however, attempt to ignore constant size factors like:
kvzalloc(4 * 1024, gfp)
though any constants defined via macros get caught up in the conversion.
Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.
The Coccinelle script used for this was:
// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@
(
kvzalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
kvzalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)
// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@
(
kvzalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
kvzalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
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kvzalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
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kvzalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)
// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@
(
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * (COUNT_ID)
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * COUNT_ID
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * (COUNT_CONST)
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * COUNT_CONST
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * (COUNT_ID)
+ COUNT_ID, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * COUNT_ID
+ COUNT_ID, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * (COUNT_CONST)
+ COUNT_CONST, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * COUNT_CONST
+ COUNT_CONST, sizeof(THING)
, ...)
)
// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@
- kvzalloc
+ kvcalloc
(
- SIZE * COUNT
+ COUNT, SIZE
, ...)
// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@
(
kvzalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kvzalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kvzalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kvzalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)
// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@
(
kvzalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kvzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kvzalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kvzalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kvzalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
kvzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)
// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@
(
kvzalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)
// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@
(
kvzalloc(C1 * C2 * C3, ...)
|
kvzalloc(
- (E1) * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
|
kvzalloc(
- (E1) * (E2) * E3
+ array3_size(E1, E2, E3)
, ...)
|
kvzalloc(
- (E1) * (E2) * (E3)
+ array3_size(E1, E2, E3)
, ...)
|
kvzalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)
// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@
(
kvzalloc(sizeof(THING) * C2, ...)
|
kvzalloc(sizeof(TYPE) * C2, ...)
|
kvzalloc(C1 * C2 * C3, ...)
|
kvzalloc(C1 * C2, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * (E2)
+ E2, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * E2
+ E2, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * (E2)
+ E2, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * E2
+ E2, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- (E1) * E2
+ E1, E2
, ...)
|
- kvzalloc
+ kvcalloc
(
- (E1) * (E2)
+ E1, E2
, ...)
|
- kvzalloc
+ kvcalloc
(
- E1 * E2
+ E1, E2
, ...)
)
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 00:04:48 +03:00
|
|
|
slots = kvcalloc(SWAP_SLOTS_CACHE_SIZE, sizeof(swp_entry_t),
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
GFP_KERNEL);
|
2017-02-23 02:45:39 +03:00
|
|
|
if (!slots)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
treewide: kvzalloc() -> kvcalloc()
The kvzalloc() function has a 2-factor argument form, kvcalloc(). This
patch replaces cases of:
kvzalloc(a * b, gfp)
with:
kvcalloc(a * b, gfp)
as well as handling cases of:
kvzalloc(a * b * c, gfp)
with:
kvzalloc(array3_size(a, b, c), gfp)
as it's slightly less ugly than:
kvcalloc(array_size(a, b), c, gfp)
This does, however, attempt to ignore constant size factors like:
kvzalloc(4 * 1024, gfp)
though any constants defined via macros get caught up in the conversion.
Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.
The Coccinelle script used for this was:
// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@
(
kvzalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
kvzalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)
// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@
(
kvzalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
kvzalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
kvzalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
kvzalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
kvzalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)
// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@
(
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * (COUNT_ID)
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * COUNT_ID
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * (COUNT_CONST)
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * COUNT_CONST
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * (COUNT_ID)
+ COUNT_ID, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * COUNT_ID
+ COUNT_ID, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * (COUNT_CONST)
+ COUNT_CONST, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * COUNT_CONST
+ COUNT_CONST, sizeof(THING)
, ...)
)
// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@
- kvzalloc
+ kvcalloc
(
- SIZE * COUNT
+ COUNT, SIZE
, ...)
// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@
(
kvzalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kvzalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kvzalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kvzalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kvzalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)
// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@
(
kvzalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kvzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kvzalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kvzalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kvzalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
kvzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)
// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@
(
kvzalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kvzalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)
// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@
(
kvzalloc(C1 * C2 * C3, ...)
|
kvzalloc(
- (E1) * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
|
kvzalloc(
- (E1) * (E2) * E3
+ array3_size(E1, E2, E3)
, ...)
|
kvzalloc(
- (E1) * (E2) * (E3)
+ array3_size(E1, E2, E3)
, ...)
|
kvzalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)
// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@
(
kvzalloc(sizeof(THING) * C2, ...)
|
kvzalloc(sizeof(TYPE) * C2, ...)
|
kvzalloc(C1 * C2 * C3, ...)
|
kvzalloc(C1 * C2, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * (E2)
+ E2, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(TYPE) * E2
+ E2, sizeof(TYPE)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * (E2)
+ E2, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- sizeof(THING) * E2
+ E2, sizeof(THING)
, ...)
|
- kvzalloc
+ kvcalloc
(
- (E1) * E2
+ E1, E2
, ...)
|
- kvzalloc
+ kvcalloc
(
- (E1) * (E2)
+ E1, E2
, ...)
|
- kvzalloc
+ kvcalloc
(
- E1 * E2
+ E1, E2
, ...)
)
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 00:04:48 +03:00
|
|
|
slots_ret = kvcalloc(SWAP_SLOTS_CACHE_SIZE, sizeof(swp_entry_t),
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
GFP_KERNEL);
|
2017-02-23 02:45:39 +03:00
|
|
|
if (!slots_ret) {
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
kvfree(slots);
|
2017-02-23 02:45:39 +03:00
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
|
|
|
mutex_lock(&swap_slots_cache_mutex);
|
|
|
|
cache = &per_cpu(swp_slots, cpu);
|
|
|
|
if (cache->slots || cache->slots_ret)
|
|
|
|
/* cache already allocated */
|
|
|
|
goto out;
|
|
|
|
if (!cache->lock_initialized) {
|
|
|
|
mutex_init(&cache->alloc_lock);
|
|
|
|
spin_lock_init(&cache->free_lock);
|
|
|
|
cache->lock_initialized = true;
|
|
|
|
}
|
|
|
|
cache->nr = 0;
|
|
|
|
cache->cur = 0;
|
|
|
|
cache->n_ret = 0;
|
2017-11-16 04:34:18 +03:00
|
|
|
/*
|
|
|
|
* We initialized alloc_lock and free_lock earlier. We use
|
|
|
|
* !cache->slots or !cache->slots_ret to know if it is safe to acquire
|
|
|
|
* the corresponding lock and use the cache. Memory barrier below
|
|
|
|
* ensures the assumption.
|
|
|
|
*/
|
|
|
|
mb();
|
2017-02-23 02:45:39 +03:00
|
|
|
cache->slots = slots;
|
|
|
|
slots = NULL;
|
|
|
|
cache->slots_ret = slots_ret;
|
|
|
|
slots_ret = NULL;
|
|
|
|
out:
|
|
|
|
mutex_unlock(&swap_slots_cache_mutex);
|
|
|
|
if (slots)
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
kvfree(slots);
|
2017-02-23 02:45:39 +03:00
|
|
|
if (slots_ret)
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
kvfree(slots_ret);
|
2017-02-23 02:45:39 +03:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void drain_slots_cache_cpu(unsigned int cpu, unsigned int type,
|
|
|
|
bool free_slots)
|
|
|
|
{
|
|
|
|
struct swap_slots_cache *cache;
|
|
|
|
swp_entry_t *slots = NULL;
|
|
|
|
|
|
|
|
cache = &per_cpu(swp_slots, cpu);
|
|
|
|
if ((type & SLOTS_CACHE) && cache->slots) {
|
|
|
|
mutex_lock(&cache->alloc_lock);
|
|
|
|
swapcache_free_entries(cache->slots + cache->cur, cache->nr);
|
|
|
|
cache->cur = 0;
|
|
|
|
cache->nr = 0;
|
|
|
|
if (free_slots && cache->slots) {
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
kvfree(cache->slots);
|
2017-02-23 02:45:39 +03:00
|
|
|
cache->slots = NULL;
|
|
|
|
}
|
|
|
|
mutex_unlock(&cache->alloc_lock);
|
|
|
|
}
|
|
|
|
if ((type & SLOTS_CACHE_RET) && cache->slots_ret) {
|
|
|
|
spin_lock_irq(&cache->free_lock);
|
|
|
|
swapcache_free_entries(cache->slots_ret, cache->n_ret);
|
|
|
|
cache->n_ret = 0;
|
|
|
|
if (free_slots && cache->slots_ret) {
|
|
|
|
slots = cache->slots_ret;
|
|
|
|
cache->slots_ret = NULL;
|
|
|
|
}
|
|
|
|
spin_unlock_irq(&cache->free_lock);
|
|
|
|
if (slots)
|
mm, swap: use kvzalloc to allocate some swap data structures
Now vzalloc() is used in swap code to allocate various data structures,
such as swap cache, swap slots cache, cluster info, etc. Because the
size may be too large on some system, so that normal kzalloc() may fail.
But using kzalloc() has some advantages, for example, less memory
fragmentation, less TLB pressure, etc. So change the data structure
allocation in swap code to use kvzalloc() which will try kzalloc()
firstly, and fallback to vzalloc() if kzalloc() failed.
In general, although kmalloc() will reduce the number of high-order
pages in short term, vmalloc() will cause more pain for memory
fragmentation in the long term. And the swap data structure allocation
that is changed in this patch is expected to be long term allocation.
From Dave Hansen:
"for example, we have a two-page data structure. vmalloc() takes two
effectively random order-0 pages, probably from two different 2M pages
and pins them. That "kills" two 2M pages. kmalloc(), allocating two
*contiguous* pages, will not cross a 2M boundary. That means it will
only "kill" the possibility of a single 2M page. More 2M pages == less
fragmentation.
The allocation in this patch occurs during swap on time, which is
usually done during system boot, so usually we have high opportunity to
allocate the contiguous pages successfully.
The allocation for swap_map[] in struct swap_info_struct is not changed,
because that is usually quite large and vmalloc_to_page() is used for
it. That makes it a little harder to change.
Link: http://lkml.kernel.org/r/20170407064911.25447-1-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-09 01:57:40 +03:00
|
|
|
kvfree(slots);
|
2017-02-23 02:45:39 +03:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __drain_swap_slots_cache(unsigned int type)
|
|
|
|
{
|
|
|
|
unsigned int cpu;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This function is called during
|
|
|
|
* 1) swapoff, when we have to make sure no
|
|
|
|
* left over slots are in cache when we remove
|
|
|
|
* a swap device;
|
|
|
|
* 2) disabling of swap slot cache, when we run low
|
|
|
|
* on swap slots when allocating memory and need
|
|
|
|
* to return swap slots to global pool.
|
|
|
|
*
|
|
|
|
* We cannot acquire cpu hot plug lock here as
|
|
|
|
* this function can be invoked in the cpu
|
|
|
|
* hot plug path:
|
|
|
|
* cpu_up -> lock cpu_hotplug -> cpu hotplug state callback
|
|
|
|
* -> memory allocation -> direct reclaim -> get_swap_page
|
|
|
|
* -> drain_swap_slots_cache
|
|
|
|
*
|
|
|
|
* Hence the loop over current online cpu below could miss cpu that
|
|
|
|
* is being brought online but not yet marked as online.
|
|
|
|
* That is okay as we do not schedule and run anything on a
|
|
|
|
* cpu before it has been marked online. Hence, we will not
|
|
|
|
* fill any swap slots in slots cache of such cpu.
|
|
|
|
* There are no slots on such cpu that need to be drained.
|
|
|
|
*/
|
|
|
|
for_each_online_cpu(cpu)
|
|
|
|
drain_slots_cache_cpu(cpu, type, false);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int free_slot_cache(unsigned int cpu)
|
|
|
|
{
|
|
|
|
mutex_lock(&swap_slots_cache_mutex);
|
|
|
|
drain_slots_cache_cpu(cpu, SLOTS_CACHE | SLOTS_CACHE_RET, true);
|
|
|
|
mutex_unlock(&swap_slots_cache_mutex);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int enable_swap_slots_cache(void)
|
|
|
|
{
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
mutex_lock(&swap_slots_cache_enable_mutex);
|
|
|
|
if (swap_slot_cache_initialized) {
|
|
|
|
__reenable_swap_slots_cache();
|
|
|
|
goto out_unlock;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "swap_slots_cache",
|
|
|
|
alloc_swap_slot_cache, free_slot_cache);
|
2017-05-04 00:54:48 +03:00
|
|
|
if (WARN_ONCE(ret < 0, "Cache allocation failed (%s), operating "
|
|
|
|
"without swap slots cache.\n", __func__))
|
2017-02-23 02:45:39 +03:00
|
|
|
goto out_unlock;
|
2017-05-04 00:54:48 +03:00
|
|
|
|
2017-02-23 02:45:39 +03:00
|
|
|
swap_slot_cache_initialized = true;
|
|
|
|
__reenable_swap_slots_cache();
|
|
|
|
out_unlock:
|
|
|
|
mutex_unlock(&swap_slots_cache_enable_mutex);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* called with swap slot cache's alloc lock held */
|
|
|
|
static int refill_swap_slots_cache(struct swap_slots_cache *cache)
|
|
|
|
{
|
|
|
|
if (!use_swap_slot_cache || cache->nr)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
cache->cur = 0;
|
|
|
|
if (swap_slot_cache_active)
|
mm, THP, swap: delay splitting THP during swap out
Patch series "THP swap: Delay splitting THP during swapping out", v11.
This patchset is to optimize the performance of Transparent Huge Page
(THP) swap.
Recently, the performance of the storage devices improved so fast that
we cannot saturate the disk bandwidth with single logical CPU when do
page swap out even on a high-end server machine. Because the
performance of the storage device improved faster than that of single
logical CPU. And it seems that the trend will not change in the near
future. On the other hand, the THP becomes more and more popular
because of increased memory size. So it becomes necessary to optimize
THP swap performance.
The advantages of the THP swap support include:
- Batch the swap operations for the THP to reduce lock
acquiring/releasing, including allocating/freeing the swap space,
adding/deleting to/from the swap cache, and writing/reading the swap
space, etc. This will help improve the performance of the THP swap.
- The THP swap space read/write will be 2M sequential IO. It is
particularly helpful for the swap read, which are usually 4k random
IO. This will improve the performance of the THP swap too.
- It will help the memory fragmentation, especially when the THP is
heavily used by the applications. The 2M continuous pages will be
free up after THP swapping out.
- It will improve the THP utilization on the system with the swap
turned on. Because the speed for khugepaged to collapse the normal
pages into the THP is quite slow. After the THP is split during the
swapping out, it will take quite long time for the normal pages to
collapse back into the THP after being swapped in. The high THP
utilization helps the efficiency of the page based memory management
too.
There are some concerns regarding THP swap in, mainly because possible
enlarged read/write IO size (for swap in/out) may put more overhead on
the storage device. To deal with that, the THP swap in should be turned
on only when necessary. For example, it can be selected via
"always/never/madvise" logic, to be turned on globally, turned off
globally, or turned on only for VMA with MADV_HUGEPAGE, etc.
This patchset is the first step for the THP swap support. The plan is
to delay splitting THP step by step, finally avoid splitting THP during
the THP swapping out and swap out/in the THP as a whole.
As the first step, in this patchset, the splitting huge page is delayed
from almost the first step of swapping out to after allocating the swap
space for the THP and adding the THP into the swap cache. This will
reduce lock acquiring/releasing for the locks used for the swap cache
management.
With the patchset, the swap out throughput improves 15.5% (from about
3.73GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
This patch (of 5):
In this patch, splitting huge page is delayed from almost the first step
of swapping out to after allocating the swap space for the THP
(Transparent Huge Page) and adding the THP into the swap cache. This
will batch the corresponding operation, thus improve THP swap out
throughput.
This is the first step for the THP swap optimization. The plan is to
delay splitting the THP step by step and avoid splitting the THP
finally.
In this patch, one swap cluster is used to hold the contents of each THP
swapped out. So, the size of the swap cluster is changed to that of the
THP (Transparent Huge Page) on x86_64 architecture (512). For other
architectures which want such THP swap optimization,
ARCH_USES_THP_SWAP_CLUSTER needs to be selected in the Kconfig file for
the architecture. In effect, this will enlarge swap cluster size by 2
times on x86_64. Which may make it harder to find a free cluster when
the swap space becomes fragmented. So that, this may reduce the
continuous swap space allocation and sequential write in theory. The
performance test in 0day shows no regressions caused by this.
In the future of THP swap optimization, some information of the swapped
out THP (such as compound map count) will be recorded in the
swap_cluster_info data structure.
The mem cgroup swap accounting functions are enhanced to support charge
or uncharge a swap cluster backing a THP as a whole.
The swap cluster allocate/free functions are added to allocate/free a
swap cluster for a THP. A fair simple algorithm is used for swap
cluster allocation, that is, only the first swap device in priority list
will be tried to allocate the swap cluster. The function will fail if
the trying is not successful, and the caller will fallback to allocate a
single swap slot instead. This works good enough for normal cases. If
the difference of the number of the free swap clusters among multiple
swap devices is significant, it is possible that some THPs are split
earlier than necessary. For example, this could be caused by big size
difference among multiple swap devices.
The swap cache functions is enhanced to support add/delete THP to/from
the swap cache as a set of (HPAGE_PMD_NR) sub-pages. This may be
enhanced in the future with multi-order radix tree. But because we will
split the THP soon during swapping out, that optimization doesn't make
much sense for this first step.
The THP splitting functions are enhanced to support to split THP in swap
cache during swapping out. The page lock will be held during allocating
the swap cluster, adding the THP into the swap cache and splitting the
THP. So in the code path other than swapping out, if the THP need to be
split, the PageSwapCache(THP) will be always false.
The swap cluster is only available for SSD, so the THP swap optimization
in this patchset has no effect for HDD.
[ying.huang@intel.com: fix two issues in THP optimize patch]
Link: http://lkml.kernel.org/r/87k25ed8zo.fsf@yhuang-dev.intel.com
[hannes@cmpxchg.org: extensive cleanups and simplifications, reduce code size]
Link: http://lkml.kernel.org/r/20170515112522.32457-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org> [for config option]
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for changes in huge_memory.c and huge_mm.h]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-07 01:37:18 +03:00
|
|
|
cache->nr = get_swap_pages(SWAP_SLOTS_CACHE_SIZE, false,
|
|
|
|
cache->slots);
|
2017-02-23 02:45:39 +03:00
|
|
|
|
|
|
|
return cache->nr;
|
|
|
|
}
|
|
|
|
|
|
|
|
int free_swap_slot(swp_entry_t entry)
|
|
|
|
{
|
|
|
|
struct swap_slots_cache *cache;
|
|
|
|
|
2017-07-11 01:49:29 +03:00
|
|
|
cache = raw_cpu_ptr(&swp_slots);
|
2017-11-16 04:34:18 +03:00
|
|
|
if (likely(use_swap_slot_cache && cache->slots_ret)) {
|
2017-02-23 02:45:39 +03:00
|
|
|
spin_lock_irq(&cache->free_lock);
|
|
|
|
/* Swap slots cache may be deactivated before acquiring lock */
|
2017-07-11 01:49:29 +03:00
|
|
|
if (!use_swap_slot_cache || !cache->slots_ret) {
|
2017-02-23 02:45:39 +03:00
|
|
|
spin_unlock_irq(&cache->free_lock);
|
|
|
|
goto direct_free;
|
|
|
|
}
|
|
|
|
if (cache->n_ret >= SWAP_SLOTS_CACHE_SIZE) {
|
|
|
|
/*
|
|
|
|
* Return slots to global pool.
|
|
|
|
* The current swap_map value is SWAP_HAS_CACHE.
|
|
|
|
* Set it to 0 to indicate it is available for
|
|
|
|
* allocation in global pool
|
|
|
|
*/
|
|
|
|
swapcache_free_entries(cache->slots_ret, cache->n_ret);
|
|
|
|
cache->n_ret = 0;
|
|
|
|
}
|
|
|
|
cache->slots_ret[cache->n_ret++] = entry;
|
|
|
|
spin_unlock_irq(&cache->free_lock);
|
|
|
|
} else {
|
|
|
|
direct_free:
|
|
|
|
swapcache_free_entries(&entry, 1);
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
mm, THP, swap: delay splitting THP during swap out
Patch series "THP swap: Delay splitting THP during swapping out", v11.
This patchset is to optimize the performance of Transparent Huge Page
(THP) swap.
Recently, the performance of the storage devices improved so fast that
we cannot saturate the disk bandwidth with single logical CPU when do
page swap out even on a high-end server machine. Because the
performance of the storage device improved faster than that of single
logical CPU. And it seems that the trend will not change in the near
future. On the other hand, the THP becomes more and more popular
because of increased memory size. So it becomes necessary to optimize
THP swap performance.
The advantages of the THP swap support include:
- Batch the swap operations for the THP to reduce lock
acquiring/releasing, including allocating/freeing the swap space,
adding/deleting to/from the swap cache, and writing/reading the swap
space, etc. This will help improve the performance of the THP swap.
- The THP swap space read/write will be 2M sequential IO. It is
particularly helpful for the swap read, which are usually 4k random
IO. This will improve the performance of the THP swap too.
- It will help the memory fragmentation, especially when the THP is
heavily used by the applications. The 2M continuous pages will be
free up after THP swapping out.
- It will improve the THP utilization on the system with the swap
turned on. Because the speed for khugepaged to collapse the normal
pages into the THP is quite slow. After the THP is split during the
swapping out, it will take quite long time for the normal pages to
collapse back into the THP after being swapped in. The high THP
utilization helps the efficiency of the page based memory management
too.
There are some concerns regarding THP swap in, mainly because possible
enlarged read/write IO size (for swap in/out) may put more overhead on
the storage device. To deal with that, the THP swap in should be turned
on only when necessary. For example, it can be selected via
"always/never/madvise" logic, to be turned on globally, turned off
globally, or turned on only for VMA with MADV_HUGEPAGE, etc.
This patchset is the first step for the THP swap support. The plan is
to delay splitting THP step by step, finally avoid splitting THP during
the THP swapping out and swap out/in the THP as a whole.
As the first step, in this patchset, the splitting huge page is delayed
from almost the first step of swapping out to after allocating the swap
space for the THP and adding the THP into the swap cache. This will
reduce lock acquiring/releasing for the locks used for the swap cache
management.
With the patchset, the swap out throughput improves 15.5% (from about
3.73GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
This patch (of 5):
In this patch, splitting huge page is delayed from almost the first step
of swapping out to after allocating the swap space for the THP
(Transparent Huge Page) and adding the THP into the swap cache. This
will batch the corresponding operation, thus improve THP swap out
throughput.
This is the first step for the THP swap optimization. The plan is to
delay splitting the THP step by step and avoid splitting the THP
finally.
In this patch, one swap cluster is used to hold the contents of each THP
swapped out. So, the size of the swap cluster is changed to that of the
THP (Transparent Huge Page) on x86_64 architecture (512). For other
architectures which want such THP swap optimization,
ARCH_USES_THP_SWAP_CLUSTER needs to be selected in the Kconfig file for
the architecture. In effect, this will enlarge swap cluster size by 2
times on x86_64. Which may make it harder to find a free cluster when
the swap space becomes fragmented. So that, this may reduce the
continuous swap space allocation and sequential write in theory. The
performance test in 0day shows no regressions caused by this.
In the future of THP swap optimization, some information of the swapped
out THP (such as compound map count) will be recorded in the
swap_cluster_info data structure.
The mem cgroup swap accounting functions are enhanced to support charge
or uncharge a swap cluster backing a THP as a whole.
The swap cluster allocate/free functions are added to allocate/free a
swap cluster for a THP. A fair simple algorithm is used for swap
cluster allocation, that is, only the first swap device in priority list
will be tried to allocate the swap cluster. The function will fail if
the trying is not successful, and the caller will fallback to allocate a
single swap slot instead. This works good enough for normal cases. If
the difference of the number of the free swap clusters among multiple
swap devices is significant, it is possible that some THPs are split
earlier than necessary. For example, this could be caused by big size
difference among multiple swap devices.
The swap cache functions is enhanced to support add/delete THP to/from
the swap cache as a set of (HPAGE_PMD_NR) sub-pages. This may be
enhanced in the future with multi-order radix tree. But because we will
split the THP soon during swapping out, that optimization doesn't make
much sense for this first step.
The THP splitting functions are enhanced to support to split THP in swap
cache during swapping out. The page lock will be held during allocating
the swap cluster, adding the THP into the swap cache and splitting the
THP. So in the code path other than swapping out, if the THP need to be
split, the PageSwapCache(THP) will be always false.
The swap cluster is only available for SSD, so the THP swap optimization
in this patchset has no effect for HDD.
[ying.huang@intel.com: fix two issues in THP optimize patch]
Link: http://lkml.kernel.org/r/87k25ed8zo.fsf@yhuang-dev.intel.com
[hannes@cmpxchg.org: extensive cleanups and simplifications, reduce code size]
Link: http://lkml.kernel.org/r/20170515112522.32457-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org> [for config option]
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for changes in huge_memory.c and huge_mm.h]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-07 01:37:18 +03:00
|
|
|
swp_entry_t get_swap_page(struct page *page)
|
2017-02-23 02:45:39 +03:00
|
|
|
{
|
|
|
|
swp_entry_t entry, *pentry;
|
|
|
|
struct swap_slots_cache *cache;
|
|
|
|
|
mm, THP, swap: delay splitting THP during swap out
Patch series "THP swap: Delay splitting THP during swapping out", v11.
This patchset is to optimize the performance of Transparent Huge Page
(THP) swap.
Recently, the performance of the storage devices improved so fast that
we cannot saturate the disk bandwidth with single logical CPU when do
page swap out even on a high-end server machine. Because the
performance of the storage device improved faster than that of single
logical CPU. And it seems that the trend will not change in the near
future. On the other hand, the THP becomes more and more popular
because of increased memory size. So it becomes necessary to optimize
THP swap performance.
The advantages of the THP swap support include:
- Batch the swap operations for the THP to reduce lock
acquiring/releasing, including allocating/freeing the swap space,
adding/deleting to/from the swap cache, and writing/reading the swap
space, etc. This will help improve the performance of the THP swap.
- The THP swap space read/write will be 2M sequential IO. It is
particularly helpful for the swap read, which are usually 4k random
IO. This will improve the performance of the THP swap too.
- It will help the memory fragmentation, especially when the THP is
heavily used by the applications. The 2M continuous pages will be
free up after THP swapping out.
- It will improve the THP utilization on the system with the swap
turned on. Because the speed for khugepaged to collapse the normal
pages into the THP is quite slow. After the THP is split during the
swapping out, it will take quite long time for the normal pages to
collapse back into the THP after being swapped in. The high THP
utilization helps the efficiency of the page based memory management
too.
There are some concerns regarding THP swap in, mainly because possible
enlarged read/write IO size (for swap in/out) may put more overhead on
the storage device. To deal with that, the THP swap in should be turned
on only when necessary. For example, it can be selected via
"always/never/madvise" logic, to be turned on globally, turned off
globally, or turned on only for VMA with MADV_HUGEPAGE, etc.
This patchset is the first step for the THP swap support. The plan is
to delay splitting THP step by step, finally avoid splitting THP during
the THP swapping out and swap out/in the THP as a whole.
As the first step, in this patchset, the splitting huge page is delayed
from almost the first step of swapping out to after allocating the swap
space for the THP and adding the THP into the swap cache. This will
reduce lock acquiring/releasing for the locks used for the swap cache
management.
With the patchset, the swap out throughput improves 15.5% (from about
3.73GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
This patch (of 5):
In this patch, splitting huge page is delayed from almost the first step
of swapping out to after allocating the swap space for the THP
(Transparent Huge Page) and adding the THP into the swap cache. This
will batch the corresponding operation, thus improve THP swap out
throughput.
This is the first step for the THP swap optimization. The plan is to
delay splitting the THP step by step and avoid splitting the THP
finally.
In this patch, one swap cluster is used to hold the contents of each THP
swapped out. So, the size of the swap cluster is changed to that of the
THP (Transparent Huge Page) on x86_64 architecture (512). For other
architectures which want such THP swap optimization,
ARCH_USES_THP_SWAP_CLUSTER needs to be selected in the Kconfig file for
the architecture. In effect, this will enlarge swap cluster size by 2
times on x86_64. Which may make it harder to find a free cluster when
the swap space becomes fragmented. So that, this may reduce the
continuous swap space allocation and sequential write in theory. The
performance test in 0day shows no regressions caused by this.
In the future of THP swap optimization, some information of the swapped
out THP (such as compound map count) will be recorded in the
swap_cluster_info data structure.
The mem cgroup swap accounting functions are enhanced to support charge
or uncharge a swap cluster backing a THP as a whole.
The swap cluster allocate/free functions are added to allocate/free a
swap cluster for a THP. A fair simple algorithm is used for swap
cluster allocation, that is, only the first swap device in priority list
will be tried to allocate the swap cluster. The function will fail if
the trying is not successful, and the caller will fallback to allocate a
single swap slot instead. This works good enough for normal cases. If
the difference of the number of the free swap clusters among multiple
swap devices is significant, it is possible that some THPs are split
earlier than necessary. For example, this could be caused by big size
difference among multiple swap devices.
The swap cache functions is enhanced to support add/delete THP to/from
the swap cache as a set of (HPAGE_PMD_NR) sub-pages. This may be
enhanced in the future with multi-order radix tree. But because we will
split the THP soon during swapping out, that optimization doesn't make
much sense for this first step.
The THP splitting functions are enhanced to support to split THP in swap
cache during swapping out. The page lock will be held during allocating
the swap cluster, adding the THP into the swap cache and splitting the
THP. So in the code path other than swapping out, if the THP need to be
split, the PageSwapCache(THP) will be always false.
The swap cluster is only available for SSD, so the THP swap optimization
in this patchset has no effect for HDD.
[ying.huang@intel.com: fix two issues in THP optimize patch]
Link: http://lkml.kernel.org/r/87k25ed8zo.fsf@yhuang-dev.intel.com
[hannes@cmpxchg.org: extensive cleanups and simplifications, reduce code size]
Link: http://lkml.kernel.org/r/20170515112522.32457-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org> [for config option]
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for changes in huge_memory.c and huge_mm.h]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-07 01:37:18 +03:00
|
|
|
entry.val = 0;
|
|
|
|
|
|
|
|
if (PageTransHuge(page)) {
|
|
|
|
if (IS_ENABLED(CONFIG_THP_SWAP))
|
|
|
|
get_swap_pages(1, true, &entry);
|
2018-06-08 03:05:31 +03:00
|
|
|
goto out;
|
mm, THP, swap: delay splitting THP during swap out
Patch series "THP swap: Delay splitting THP during swapping out", v11.
This patchset is to optimize the performance of Transparent Huge Page
(THP) swap.
Recently, the performance of the storage devices improved so fast that
we cannot saturate the disk bandwidth with single logical CPU when do
page swap out even on a high-end server machine. Because the
performance of the storage device improved faster than that of single
logical CPU. And it seems that the trend will not change in the near
future. On the other hand, the THP becomes more and more popular
because of increased memory size. So it becomes necessary to optimize
THP swap performance.
The advantages of the THP swap support include:
- Batch the swap operations for the THP to reduce lock
acquiring/releasing, including allocating/freeing the swap space,
adding/deleting to/from the swap cache, and writing/reading the swap
space, etc. This will help improve the performance of the THP swap.
- The THP swap space read/write will be 2M sequential IO. It is
particularly helpful for the swap read, which are usually 4k random
IO. This will improve the performance of the THP swap too.
- It will help the memory fragmentation, especially when the THP is
heavily used by the applications. The 2M continuous pages will be
free up after THP swapping out.
- It will improve the THP utilization on the system with the swap
turned on. Because the speed for khugepaged to collapse the normal
pages into the THP is quite slow. After the THP is split during the
swapping out, it will take quite long time for the normal pages to
collapse back into the THP after being swapped in. The high THP
utilization helps the efficiency of the page based memory management
too.
There are some concerns regarding THP swap in, mainly because possible
enlarged read/write IO size (for swap in/out) may put more overhead on
the storage device. To deal with that, the THP swap in should be turned
on only when necessary. For example, it can be selected via
"always/never/madvise" logic, to be turned on globally, turned off
globally, or turned on only for VMA with MADV_HUGEPAGE, etc.
This patchset is the first step for the THP swap support. The plan is
to delay splitting THP step by step, finally avoid splitting THP during
the THP swapping out and swap out/in the THP as a whole.
As the first step, in this patchset, the splitting huge page is delayed
from almost the first step of swapping out to after allocating the swap
space for the THP and adding the THP into the swap cache. This will
reduce lock acquiring/releasing for the locks used for the swap cache
management.
With the patchset, the swap out throughput improves 15.5% (from about
3.73GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
This patch (of 5):
In this patch, splitting huge page is delayed from almost the first step
of swapping out to after allocating the swap space for the THP
(Transparent Huge Page) and adding the THP into the swap cache. This
will batch the corresponding operation, thus improve THP swap out
throughput.
This is the first step for the THP swap optimization. The plan is to
delay splitting the THP step by step and avoid splitting the THP
finally.
In this patch, one swap cluster is used to hold the contents of each THP
swapped out. So, the size of the swap cluster is changed to that of the
THP (Transparent Huge Page) on x86_64 architecture (512). For other
architectures which want such THP swap optimization,
ARCH_USES_THP_SWAP_CLUSTER needs to be selected in the Kconfig file for
the architecture. In effect, this will enlarge swap cluster size by 2
times on x86_64. Which may make it harder to find a free cluster when
the swap space becomes fragmented. So that, this may reduce the
continuous swap space allocation and sequential write in theory. The
performance test in 0day shows no regressions caused by this.
In the future of THP swap optimization, some information of the swapped
out THP (such as compound map count) will be recorded in the
swap_cluster_info data structure.
The mem cgroup swap accounting functions are enhanced to support charge
or uncharge a swap cluster backing a THP as a whole.
The swap cluster allocate/free functions are added to allocate/free a
swap cluster for a THP. A fair simple algorithm is used for swap
cluster allocation, that is, only the first swap device in priority list
will be tried to allocate the swap cluster. The function will fail if
the trying is not successful, and the caller will fallback to allocate a
single swap slot instead. This works good enough for normal cases. If
the difference of the number of the free swap clusters among multiple
swap devices is significant, it is possible that some THPs are split
earlier than necessary. For example, this could be caused by big size
difference among multiple swap devices.
The swap cache functions is enhanced to support add/delete THP to/from
the swap cache as a set of (HPAGE_PMD_NR) sub-pages. This may be
enhanced in the future with multi-order radix tree. But because we will
split the THP soon during swapping out, that optimization doesn't make
much sense for this first step.
The THP splitting functions are enhanced to support to split THP in swap
cache during swapping out. The page lock will be held during allocating
the swap cluster, adding the THP into the swap cache and splitting the
THP. So in the code path other than swapping out, if the THP need to be
split, the PageSwapCache(THP) will be always false.
The swap cluster is only available for SSD, so the THP swap optimization
in this patchset has no effect for HDD.
[ying.huang@intel.com: fix two issues in THP optimize patch]
Link: http://lkml.kernel.org/r/87k25ed8zo.fsf@yhuang-dev.intel.com
[hannes@cmpxchg.org: extensive cleanups and simplifications, reduce code size]
Link: http://lkml.kernel.org/r/20170515112522.32457-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org> [for config option]
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for changes in huge_memory.c and huge_mm.h]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-07 01:37:18 +03:00
|
|
|
}
|
|
|
|
|
2017-02-23 02:45:39 +03:00
|
|
|
/*
|
|
|
|
* Preemption is allowed here, because we may sleep
|
|
|
|
* in refill_swap_slots_cache(). But it is safe, because
|
|
|
|
* accesses to the per-CPU data structure are protected by the
|
|
|
|
* mutex cache->alloc_lock.
|
|
|
|
*
|
|
|
|
* The alloc path here does not touch cache->slots_ret
|
|
|
|
* so cache->free_lock is not taken.
|
|
|
|
*/
|
|
|
|
cache = raw_cpu_ptr(&swp_slots);
|
|
|
|
|
2017-11-16 04:34:18 +03:00
|
|
|
if (likely(check_cache_active() && cache->slots)) {
|
2017-02-23 02:45:39 +03:00
|
|
|
mutex_lock(&cache->alloc_lock);
|
|
|
|
if (cache->slots) {
|
|
|
|
repeat:
|
|
|
|
if (cache->nr) {
|
|
|
|
pentry = &cache->slots[cache->cur++];
|
|
|
|
entry = *pentry;
|
|
|
|
pentry->val = 0;
|
|
|
|
cache->nr--;
|
|
|
|
} else {
|
|
|
|
if (refill_swap_slots_cache(cache))
|
|
|
|
goto repeat;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
mutex_unlock(&cache->alloc_lock);
|
|
|
|
if (entry.val)
|
2018-06-08 03:05:31 +03:00
|
|
|
goto out;
|
2017-02-23 02:45:39 +03:00
|
|
|
}
|
|
|
|
|
mm, THP, swap: delay splitting THP during swap out
Patch series "THP swap: Delay splitting THP during swapping out", v11.
This patchset is to optimize the performance of Transparent Huge Page
(THP) swap.
Recently, the performance of the storage devices improved so fast that
we cannot saturate the disk bandwidth with single logical CPU when do
page swap out even on a high-end server machine. Because the
performance of the storage device improved faster than that of single
logical CPU. And it seems that the trend will not change in the near
future. On the other hand, the THP becomes more and more popular
because of increased memory size. So it becomes necessary to optimize
THP swap performance.
The advantages of the THP swap support include:
- Batch the swap operations for the THP to reduce lock
acquiring/releasing, including allocating/freeing the swap space,
adding/deleting to/from the swap cache, and writing/reading the swap
space, etc. This will help improve the performance of the THP swap.
- The THP swap space read/write will be 2M sequential IO. It is
particularly helpful for the swap read, which are usually 4k random
IO. This will improve the performance of the THP swap too.
- It will help the memory fragmentation, especially when the THP is
heavily used by the applications. The 2M continuous pages will be
free up after THP swapping out.
- It will improve the THP utilization on the system with the swap
turned on. Because the speed for khugepaged to collapse the normal
pages into the THP is quite slow. After the THP is split during the
swapping out, it will take quite long time for the normal pages to
collapse back into the THP after being swapped in. The high THP
utilization helps the efficiency of the page based memory management
too.
There are some concerns regarding THP swap in, mainly because possible
enlarged read/write IO size (for swap in/out) may put more overhead on
the storage device. To deal with that, the THP swap in should be turned
on only when necessary. For example, it can be selected via
"always/never/madvise" logic, to be turned on globally, turned off
globally, or turned on only for VMA with MADV_HUGEPAGE, etc.
This patchset is the first step for the THP swap support. The plan is
to delay splitting THP step by step, finally avoid splitting THP during
the THP swapping out and swap out/in the THP as a whole.
As the first step, in this patchset, the splitting huge page is delayed
from almost the first step of swapping out to after allocating the swap
space for the THP and adding the THP into the swap cache. This will
reduce lock acquiring/releasing for the locks used for the swap cache
management.
With the patchset, the swap out throughput improves 15.5% (from about
3.73GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case
with 8 processes. The test is done on a Xeon E5 v3 system. The swap
device used is a RAM simulated PMEM (persistent memory) device. To test
the sequential swapping out, the test case creates 8 processes, which
sequentially allocate and write to the anonymous pages until the RAM and
part of the swap device is used up.
This patch (of 5):
In this patch, splitting huge page is delayed from almost the first step
of swapping out to after allocating the swap space for the THP
(Transparent Huge Page) and adding the THP into the swap cache. This
will batch the corresponding operation, thus improve THP swap out
throughput.
This is the first step for the THP swap optimization. The plan is to
delay splitting the THP step by step and avoid splitting the THP
finally.
In this patch, one swap cluster is used to hold the contents of each THP
swapped out. So, the size of the swap cluster is changed to that of the
THP (Transparent Huge Page) on x86_64 architecture (512). For other
architectures which want such THP swap optimization,
ARCH_USES_THP_SWAP_CLUSTER needs to be selected in the Kconfig file for
the architecture. In effect, this will enlarge swap cluster size by 2
times on x86_64. Which may make it harder to find a free cluster when
the swap space becomes fragmented. So that, this may reduce the
continuous swap space allocation and sequential write in theory. The
performance test in 0day shows no regressions caused by this.
In the future of THP swap optimization, some information of the swapped
out THP (such as compound map count) will be recorded in the
swap_cluster_info data structure.
The mem cgroup swap accounting functions are enhanced to support charge
or uncharge a swap cluster backing a THP as a whole.
The swap cluster allocate/free functions are added to allocate/free a
swap cluster for a THP. A fair simple algorithm is used for swap
cluster allocation, that is, only the first swap device in priority list
will be tried to allocate the swap cluster. The function will fail if
the trying is not successful, and the caller will fallback to allocate a
single swap slot instead. This works good enough for normal cases. If
the difference of the number of the free swap clusters among multiple
swap devices is significant, it is possible that some THPs are split
earlier than necessary. For example, this could be caused by big size
difference among multiple swap devices.
The swap cache functions is enhanced to support add/delete THP to/from
the swap cache as a set of (HPAGE_PMD_NR) sub-pages. This may be
enhanced in the future with multi-order radix tree. But because we will
split the THP soon during swapping out, that optimization doesn't make
much sense for this first step.
The THP splitting functions are enhanced to support to split THP in swap
cache during swapping out. The page lock will be held during allocating
the swap cluster, adding the THP into the swap cache and splitting the
THP. So in the code path other than swapping out, if the THP need to be
split, the PageSwapCache(THP) will be always false.
The swap cluster is only available for SSD, so the THP swap optimization
in this patchset has no effect for HDD.
[ying.huang@intel.com: fix two issues in THP optimize patch]
Link: http://lkml.kernel.org/r/87k25ed8zo.fsf@yhuang-dev.intel.com
[hannes@cmpxchg.org: extensive cleanups and simplifications, reduce code size]
Link: http://lkml.kernel.org/r/20170515112522.32457-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org> [for config option]
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> [for changes in huge_memory.c and huge_mm.h]
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-07 01:37:18 +03:00
|
|
|
get_swap_pages(1, false, &entry);
|
2018-06-08 03:05:31 +03:00
|
|
|
out:
|
|
|
|
if (mem_cgroup_try_charge_swap(page, entry)) {
|
|
|
|
put_swap_page(page, entry);
|
|
|
|
entry.val = 0;
|
|
|
|
}
|
2017-02-23 02:45:39 +03:00
|
|
|
return entry;
|
|
|
|
}
|