Sometimes gcc mysteriously doesn't inline
very small functions we expect to be inlined. See
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122
With this .config:
http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os,
atomic_long_inc(), atomic_long_dec() and atomic_long_add()
functions get deinlined about 40 times. Examples of disassembly:
<atomic_long_inc> (21 copies, 147 calls):
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 48 ff 07 lock incq (%rdi)
5d pop %rbp
c3 retq
<atomic_long_dec> (4 copies, 14 calls) is similar to inc.
<atomic_long_add> (11 copies, 41 calls):
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 48 01 3e lock add %rdi,(%rsi)
5d pop %rbp
c3 retq
This patch fixes this via s/inline/__always_inline/.
Code size decrease after the patch is ~1.3k:
text data bss dec hex filename
92203657 20826112 36417536 149447305 8e86289 vmlinux
92202377 20826112 36417536 149446025 8e85d89 vmlinux4_atomiclong_after
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The new helper returns index of the mathing string in an array. We
would use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Occasionally we have to search for an occurrence of a string in an array
of strings. Make a simple helper for that purpose.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: David Airlie <airlied@linux.ie>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Without fix test crashes inside tagged iteration.
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After calling radix_tree_iter_retry(), 'slot' will be set to NULL. This
can cause radix_tree_next_slot() to dereference the NULL pointer. Add
Konstantin Khlebnikov's test to the regression framework.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reported-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
shmem likes to occasionally drop the lock, schedule, then reacqire the
lock and continue with the iteration from the last place it left off.
This is currently done with a pretty ugly goto. Introduce
radix_tree_iter_next() and use it throughout shmem.c.
[koct9i@gmail.com: fix bug in radix_tree_iter_next() for tagged iteration]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of a 'goto restart', we can now use radix_tree_iter_retry() to
restart from our current position. This will make a difference when
there are more ways to happen across an indirect pointer. And it
eliminates some confusing gotos.
[vbabka@suse.cz: remove now-obsolete-and-misleading comment]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Even though this is a 'can't happen' situation, use the new
radix_tree_iter_retry() pattern to eliminate a goto.
[akpm@linux-foundation.org: fix btrfs build]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is debug code which is #if 0 out.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With huge pages, it is convenient to have the radix tree be able to
return an entry that covers multiple indices. Previous attempts to deal
with the problem have involved inserting N duplicate entries, which is a
waste of memory and leads to problems trying to handle aliased tags, or
probing the tree multiple times to find alternative entries which might
cover the requested index.
This approach inserts one canonical entry into the tree for a given
range of indices, and may also insert other entries in order to ensure
that lookups find the canonical entry.
This solution only tolerates inserting powers of two that are greater
than the fanout of the tree. If we wish to expand the radix tree's
abilities to support large-ish pages that is less than the fanout at the
penultimate level of the tree, then we would need to add one more step
in lookup to ensure that any sibling nodes in the final level of the
tree are dereferenced and we return the canonical entry that they
reference.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we introduce entries that can cover multiple indices, we will need
to stop in __radix_tree_create based on the shift, not the height.
Split out for ease of bisect.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Set the 'indirect_ptr' bit on all the pointers to internal nodes, not
just on the root node. This enables the following patches to support
multi-order entries in the radix tree. This patch is split out for ease
of bisection.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This code is mostly from Andrew Morton and Nick Piggin; tarball downloaded
from http://ozlabs.org/~akpm/rtth.tar.gz with sha1sum
0ce679db9ec047296b5d1ff7a1dfaa03a7bef1bd
Some small modifications were necessary to the test harness to fix the
build with the current Linux source code.
I also made minor modifications to automatically test the radix-tree.c
and radix-tree.h files that are in the current source tree, as opposed
to a copied and slightly modified version. I am sure more could be done
to tidy up the harness, as well as adding more tests.
[koct9i@gmail.com: fix compilation]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The radix-tree header uses the __ffs() function, which is defined in
bitops.h. The current kernel headers implicitly include bitops.h, but
the userspace test harness does not.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Christian Borntraeger reported that panic_on_warn doesn't have any
effect on s390.
The panic_on_warn feature was introduced with 9e3961a097 ("kernel: add
panic_on_warn"). However it did care only for the case when
WANT_WARN_ON_SLOWPATH is defined. This is turn is only the case for
architectures which do not have an own __WARN_TAINT defined.
Other architectures which do have __WARN_TAINT defined call report_bug()
for warnings within lib/bug.c which does not call panic() in case
panic_on_warn is set.
Let's simply enable the panic_on_warn feature by adding the same code
like it was added to warn_slowpath_common() in panic.c.
This enables panic_on_warn also for arm64, parisc, powerpc, s390 and sh.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hlist_bl_unhashed() and hlist_bl_empty() are all boolean functions, so
return bool instead of int.
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Benjamin Romer is no longer a maintainer for the Unisys s-Par driver,
presently in drivers/staging/unisys/.
Signed-off-by: David Kershner <david.kershner@unisys.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows us to extract from the vmcore only the messages emitted
since the last time the ring buffer was cleared. We just have to make
sure its value is always up-to-date, when old messages are discarded to
free space in log_make_free_space() for example.
Signed-off-by: Zeyu Zhao <zzy8200@gmail.com>
Signed-off-by: Ivan Delalande <colona@arista.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
have_callable_console() must also test CON_ENABLED bit, not just
CON_ANYTIME. We may have disabled CON_ANYTIME console so printk can
wrongly assume that it's safe to call_console_drivers().
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
console_unlock() allows to cond_resched() if its caller has set
`console_may_schedule' to 1, since 8d91f8b153 ("printk: do
cond_resched() between lines while outputting to consoles").
The rules are:
-- console_lock() always sets `console_may_schedule' to 1
-- console_trylock() always sets `console_may_schedule' to 0
However, console_trylock() callers (among them is printk()) do not
always call printk() from atomic contexts, and some of them can
cond_resched() in console_unlock(), so console_trylock() can set
`console_may_schedule' to 1 for such processes.
For !CONFIG_PREEMPT_COUNT kernels, however, console_trylock() always
sets `console_may_schedule' to 0.
It's possible to drop explicit preempt_disable()/preempt_enable() in
vprintk_emit(), because console_unlock() and console_trylock() are now
smart enough:
a) console_unlock() does not cond_resched() when it's unsafe
(console_trylock() takes care of that)
b) console_unlock() does can_use_console() check.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
console_unlock() allows to cond_resched() if its caller has set
`console_may_schedule' to 1 (this functionality is present since
8d91f8b153 ("printk: do cond_resched() between lines while outputting
to consoles").
The rules are:
-- console_lock() always sets `console_may_schedule' to 1
-- console_trylock() always sets `console_may_schedule' to 0
printk() calls console_unlock() with preemption desabled, which
basically can lead to RCU stalls, watchdog soft lockups, etc. if
something is simultaneously calling printk() frequent enough (IOW,
console_sem owner always has new data to send to console divers and
can't leave console_unlock() for a long time).
printk()->console_trylock() callers do not necessarily execute in atomic
contexts, and some of them can cond_resched() in console_unlock().
console_trylock() can set `console_may_schedule' to 1 (allow
cond_resched() later in consoe_unlock()) when it's safe.
This patch (of 3):
vprintk_emit() disables preemption around console_trylock_for_printk()
and console_unlock() calls for a strong reason -- can_use_console()
check. The thing is that vprintl_emit() can be called on a CPU that is
not fully brought up yet (!cpu_online()), which potentially can cause
problems if console driver wants to access per-cpu data. A console
driver can explicitly state that it's safe to call it from !online cpu
by setting CON_ANYTIME bit in console ->flags. That's why for
!cpu_online() can_use_console() iterates all the console to find out if
there is a CON_ANYTIME console, otherwise console_unlock() must be
avoided.
can_use_console() ensures that console_unlock() call is safe in
vprintk_emit() only; console_lock() and console_trylock() are not
covered by this check. Even though call_console_drivers(), invoked from
console_cont_flush() and console_unlock(), tests `!cpu_online() &&
CON_ANYTIME' for_each_console(), it may be too late, which can result in
messages loss.
Assume that we have 2 cpus -- CPU0 is online, CPU1 is !online, and no
CON_ANYTIME consoles available.
CPU0 online CPU1 !online
console_trylock()
...
console_unlock()
console_cont_flush
spin_lock logbuf_lock
if (!cont.len) {
spin_unlock logbuf_lock
return
}
for (;;) {
vprintk_emit
spin_lock logbuf_lock
log_store
spin_unlock logbuf_lock
spin_lock logbuf_lock
!console_trylock_for_printk msg_print_text
return console_idx = log_next()
console_seq++
console_prev = msg->flags
spin_unlock logbuf_lock
call_console_drivers()
for_each_console(con) {
if (!cpu_online() &&
!(con->flags & CON_ANYTIME))
continue;
}
/*
* no message printed, we lost it
*/
vprintk_emit
spin_lock logbuf_lock
log_store
spin_unlock logbuf_lock
!console_trylock_for_printk
return
/*
* go to the beginning of the loop,
* find out there are new messages,
* lose it
*/
}
console_trylock()/console_lock() call on CPU1 may come from cpu
notifiers registered on that CPU. Since notifiers are not getting
unregistered when CPU is going DOWN, all of the notifiers receive
notifications during CPU UP. For example, on my x86_64, I see around 50
notification sent from offline CPU to itself
[swapper/2] from cpu:2 to:2 action:CPU_STARTING hotplug_hrtick
[swapper/2] from cpu:2 to:2 action:CPU_STARTING blk_mq_main_cpu_notify
[swapper/2] from cpu:2 to:2 action:CPU_STARTING blk_mq_queue_reinit_notify
[swapper/2] from cpu:2 to:2 action:CPU_STARTING console_cpu_notify
while doing
echo 0 > /sys/devices/system/cpu/cpu2/online
echo 1 > /sys/devices/system/cpu/cpu2/online
So grabbing the console_sem lock while CPU is !online is possible,
in theory.
This patch moves can_use_console() check out of
console_trylock_for_printk(). Instead it calls it in console_unlock(),
so now console_lock()/console_unlock() are also 'protected' by
can_use_console(). This also means that console_trylock_for_printk() is
not really needed anymore and can be removed.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The v850 port was removed by commits f606ddf42f and 07a887d399 in
2008. These #defines are not used in the current kernel.
Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are various email addresses for me throughout the kernel. Use the
one that will always be valid.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This has hit me a couple of times already. I would be debugging code
and the system would simply hang and then reboot. Finally, I found that
the problem was caused by WARN_ON_ONCE() and friends.
The macro WARN_ON_ONCE(condition) is defined as:
static bool __section(.data.unlikely) __warned;
int __ret_warn_once = !!(condition);
if (unlikely(__ret_warn_once))
if (WARN_ON(!__warned))
__warned = true;
unlikely(__ret_warn_once);
Which looks great and all. But what I have hit, is an issue when
WARN_ON() itself hits the same WARN_ON_ONCE() code. Because, the
variable __warned is not yet set. Then it too calls WARN_ON() and that
triggers the warning again. It keeps doing this until the stack is
overflowed and the system crashes.
By setting __warned first before calling WARN_ON() makes the original
WARN_ON_ONCE() really only warn once, and not an infinite amount of
times if the WARN_ON() also triggers the warning.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_BUG=n && CONFIG_GENERIC_BUG=y make no sense and things break:
In file included from include/linux/page-flags.h:9:0,
from kernel/bounds.c:9:
include/linux/bug.h:91:47: warning: 'struct bug_entry' declared inside parameter list
static inline int is_warning_bug(const struct bug_entry *bug)
^
include/linux/bug.h:91:47: warning: its scope is only this definition or declaration, which is probably not what you want
include/linux/bug.h: In function 'is_warning_bug':
>> include/linux/bug.h:93:12: error: dereferencing pointer to incomplete type
return bug->flags & BUGFLAG_WARNING;
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On i686 PAE enabled machine the contiguous physical area could be large
and it can cause trimming down variables in below calculation in
read_vmcore() and mmap_vmcore():
tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
That is, the types being used is like below on i686:
m->offset: unsigned long long int
m->size: unsigned long long int
*fpos: loff_t (long long int)
buflen: size_t (unsigned int)
So casting (m->offset + m->size - *fpos) by size_t means truncating a
given value by 4GB.
Suppose (m->offset + m->size - *fpos) being truncated to 0, buflen >0
then we will get tsz = 0. It is of course not an expected result.
Similarly we could also get other truncated values less than buflen.
Then the real size passed down is not correct any more.
If (m->offset + m->size - *fpos) is above 4GB, read_vmcore or
mmap_vmcore use the min_t result with truncated values being compared to
buflen. Then, fpos proceeds with the wrong value so that we reach below
bugs:
1) read_vmcore will refuse to continue so makedumpfile fails.
2) mmap_vmcore will trigger BUG_ON() in remap_pfn_range().
Use unsigned long long in min_t instead so that the variables in are not
truncated.
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Cc: Minfei Huang <mhuang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is not elegant that prompt shell does not start from new line after
executing "cat /proc/$pid/wchan". Make prompt shell start from new
line.
Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`proc_timers_operations` is only used when CONFIG_CHECKPOINT_RESTORE is
enabled.
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch provides a proc/PID/timerslack_ns interface which exposes a
task's timerslack value in nanoseconds and allows it to be changed.
This allows power/performance management software to set timer slack for
other threads according to its policy for the thread (such as when the
thread is designated foreground vs. background activity)
If the value written is non-zero, slack is set to that value. Otherwise
sets it to the default for the thread.
This interface checks that the calling task has permissions to to use
PTRACE_MODE_ATTACH_FSCREDS on the target task, so that we can ensure
arbitrary apps do not change the timer slack for other apps.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset introduces a /proc/<pid>/timerslack_ns interface which
would allow controlling processes to be able to set the timerslack value
on other processes in order to save power by avoiding wakeups (Something
Android currently does via out-of-tree patches).
The first patch tries to fix the internal timer_slack_ns usage which was
defined as a long, which limits the slack range to ~4 seconds on 32bit
systems. It converts it to a u64, which provides the same basically
unlimited slack (500 years) on both 32bit and 64bit machines.
The second patch introduces the /proc/<pid>/timerslack_ns interface
which allows the full 64bit slack range for a task to be read or set on
both 32bit and 64bit machines.
With these two patches, on a 32bit machine, after setting the slack on
bash to 10 seconds:
$ time sleep 1
real 0m10.747s
user 0m0.001s
sys 0m0.005s
The first patch is a little ugly, since I had to chase the slack delta
arguments through a number of functions converting them to u64s. Let me
know if it makes sense to break that up more or not.
Other than that things are fairly straightforward.
This patch (of 2):
The timer_slack_ns value in the task struct is currently a unsigned
long. This means that on 32bit applications, the maximum slack is just
over 4 seconds. However, on 64bit machines, its much much larger (~500
years).
This disparity could make application development a little (as well as
the default_slack) to a u64. This means both 32bit and 64bit systems
have the same effective internal slack range.
Now the existing ABI via PR_GET_TIMERSLACK and PR_SET_TIMERSLACK specify
the interface as a unsigned long, so we preserve that limitation on
32bit systems, where SET_TIMERSLACK can only set the slack to a unsigned
long value, and GET_TIMERSLACK will return ULONG_MAX if the slack is
actually larger then what can be stored by an unsigned long.
This patch also modifies hrtimer functions which specified the slack
delta as a unsigned long.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After the OOM killer is disabled during suspend operation, any
!__GFP_NOFAIL && __GFP_FS allocations are forced to fail. Thus, any
!__GFP_NOFAIL && !__GFP_FS allocations should be forced to fail as well.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While oom_killer_disable() is called by freeze_processes() after all
user threads except the current thread are frozen, it is possible that
kernel threads invoke the OOM killer and sends SIGKILL to the current
thread due to sharing the thawed victim's memory. Therefore, checking
for SIGKILL is preferable than TIF_MEMDIE.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new column to pool stats, which will tell how many pages ideally
can be freed by class compaction, so it will be easier to analyze
zsmalloc fragmentation.
At the moment, we have only numbers of FULL and ALMOST_EMPTY classes,
but they don't tell us how badly the class is fragmented internally.
The new /sys/kernel/debug/zsmalloc/zramX/classes output look as follows:
class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage freeable
[..]
12 224 0 2 146 5 8 4 4
13 240 0 0 0 0 0 1 0
14 256 1 13 1840 1672 115 1 10
15 272 0 0 0 0 0 1 0
[..]
49 816 0 3 745 735 149 1 2
51 848 3 4 361 306 76 4 8
52 864 12 14 378 268 81 3 21
54 896 1 12 117 57 26 2 12
57 944 0 0 0 0 0 3 0
[..]
Total 26 131 12709 10994 1071 134
For example, from this particular output we can easily conclude that
class-896 is heavily fragmented -- it occupies 26 pages, 12 can be freed
by compaction.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When unmapping a huge class page in zs_unmap_object, the page will be
unmapped by kmap_atomic. the "!area->huge" branch in __zs_unmap_object
is alway true, and no code set "area->huge" now, so we can drop it.
Signed-off-by: YiPing Xu <xuyiping@huawei.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have PAGE_ALIGNED() in mm.h, so let's use it instead of IS_ALIGNED()
for checking PAGE_SIZE aligned case.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mem_cgroup_print_oom_info is always called under oom_lock, so
oom_info_lock is redundant.
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
uncharge_list() does an unusual list walk because the function can take
regular lists with dedicated list_heads as well as singleton lists where
a single page is passed via the page->lru list node.
This can sometimes lead to confusion as well as suggestions to replace
the loop with a list_for_each_entry(), which wouldn't work.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Setting the original memory.limit_in_bytes hardlimit is subject to a
race condition when the desired value is below the current usage. The
code tries a few times to first reclaim and then see if the usage has
dropped to where we would like it to be, but there is no locking, and
the workload is free to continue making new charges up to the old limit.
Thus, attempting to shrink a workload relies on pure luck and hope that
the workload happens to cooperate.
To fix this in the cgroup2 memory.max knob, do it the other way round:
set the limit first, then try enforcement. And if reclaim is not able
to succeed, trigger OOM kills in the group. Keep going until the new
limit is met, we run out of OOM victims and there's only unreclaimable
memory left, or the task writing to memory.max is killed. This allows
users to shrink groups reliably, and the behavior is consistent with
what happens when new charges are attempted in excess of memory.max.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When setting memory.high below usage, nothing happens until the next
charge comes along, and then it will only reclaim its own charge and not
the now potentially huge excess of the new memory.high. This can cause
groups to stay in excess of their memory.high indefinitely.
To fix that, when shrinking memory.high, kick off a reclaim cycle that
goes after the delta.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I found that page-types is very slow and my testing shows many timeout
errors. Here's an example with a simple program allocating 1000 thps.
$ time ./page-types -p $(pgrep -f test_alloc)
...
real 0m17.201s
user 0m16.889s
sys 0m0.312s
Most of time is spent in memset(). Currently memset() clears over whole
buffer for every walk_pfn() call, which is inefficient when walk_pfn()
is called from walk_vma(), because in that case walk_pfn() is called for
each pfn. So this patch limits the zero initialization only for the
first element.
$ time ./page-types.patched -p $(pgrep -f test_alloc)
...
real 0m0.182s
user 0m0.046s
sys 0m0.135s
Fixes: 954e95584579 ("tools/vm/page-types.c: add memory cgroup dumping and filtering")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Suggested-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Denys Vlasenko
Heikki Krogerus
Andy Shevchenko
Konstantin Khlebnikov
Matthew Wilcox
Heiko Carstens
Chen Gang
David Kershner
Ivan Delalande
Sergey Senozhatsky
Rob Landley
Christoph Lameter
Steven Rostedt
Andrew Morton
Dave Young
Minfei Huang
Eric Engestrom
John Stultz
Tetsuo Handa
YiPing Xu
Shawn Lin
Vladimir Davydov
Johannes Weiner
Naoya Horiguchi