First step in pushing down the page_table_lock. init_mm.page_table_lock has
been used throughout the architectures (usually for ioremap): not to serialize
kernel address space allocation (that's usually vmlist_lock), but because
pud_alloc,pmd_alloc,pte_alloc_kernel expect caller holds it.
Reverse that: don't lock or unlock init_mm.page_table_lock in any of the
architectures; instead rely on pud_alloc,pmd_alloc,pte_alloc_kernel to take
and drop it when allocating a new one, to check lest a racing task already
did. Similarly no page_table_lock in vmalloc's map_vm_area.
Some temporary ugliness in __pud_alloc and __pmd_alloc: since they also handle
user mms, which are converted only by a later patch, for now they have to lock
differently according to whether or not it's init_mm.
If sources get muddled, there's a danger that an arch source taking
init_mm.page_table_lock will be mixed with common source also taking it (or
neither take it). So break the rules and make another change, which should
break the build for such a mismatch: remove the redundant mm arg from
pte_alloc_kernel (ppc64 scrapped its distinct ioremap_mm in 2.6.13).
Exceptions: arm26 used pte_alloc_kernel on user mm, now pte_alloc_map; ia64
used pte_alloc_map on init_mm, now pte_alloc_kernel; parisc had bad args to
pmd_alloc and pte_alloc_kernel in unused USE_HPPA_IOREMAP code; ppc64
map_io_page forgot to unlock on failure; ppc mmu_mapin_ram and ppc64 im_free
took page_table_lock for no good reason.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ia64 has expand_backing_store function for growing its Register Backing Store
vma upwards. But more complete code for this purpose is found in the
CONFIG_STACK_GROWSUP part of mm/mmap.c. Uglify its #ifdefs further to provide
expand_upwards for ia64 as well as expand_stack for parisc.
The Register Backing Store vma should be marked VM_ACCOUNT. Implement the
intention of growing it only a page at a time, instead of passing an address
outside of the vma to handle_mm_fault, with unknown consequences.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch is the minimal set of changes required by ia64 to use SPARSEMEM.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
I've solved the problem I was having with the simulator and not
booting Debian.
The problem is that the number of bits for the virtual linear array
short-format VHPT (Virtually mapped linear page table, VMLPT for
short) is being tested incorrectly.
There are two problems:
1. The PAL call that should tell the kernel the size of the
virtual address space isn't implemented for the simulator, so
the kernel uses the default 50. This is addressed separately
in dc90e95f31
2. In arch/ia64/mm/init.c there's code to calcualte the size
of the VMLPT based on the number of implemented virtual address
bits and the page size. It checks to see if the VMLPT base
address overlaps the top of the mapped region, but this check
doesn't allow for the address space hole, and in fact will
never trigger.
Here's an alternative test and panic, that I think is more accurate.
Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
I reworked how nodes with only CPUs are treated. The patch below seems
simpler to me and has eliminated the complicated routine
reassign_cpu_only_nodes. There isn't any longer the requirement
to modify ACPI NUMA information which was in large part the
complexity introduced in reassign_cpu_only_nodes.
This patch will produce a different number of nodes. For example,
reassign_cpu_only_nodes would reduce two CPUonly nodes and one memory node
configuration to one memory+CPUs node configuration. This patch
doesn't change the number of nodes which means the user will see three. Two
nodes without memory and one node with all the memory.
While doing this patch, I noticed that early_nr_phys_cpus_node isn't serving
any useful purpose. It is called once in find_pernode_space but the value
isn't used to computer pernode space.
Signed-off-by: bob.picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch introduces using the quicklists for pgd, pmd, and pte levels
by combining the alloc and free functions into a common set of routines.
This greatly simplifies the reading of this header file.
This patch is simple but necessary for large numa configurations.
It simply ensures that only pages from the local node are added to a
cpus quicklist. This prevents the trapping of pages on a remote nodes
quicklist by starting a process, touching a large number of pages to
fill pmd and pte entries, migrating to another node, and then unmapping
or exiting. With those conditions, the pages get trapped and if the
machine has more than 100 nodes of the same size, the calculation of
the pgtable high water mark will be larger than any single node so page
table cache flushing will never occur.
I ran lmbench lat_proc fork and lat_proc exec on a zx1 with and without
this patch and did not notice any change.
On an sn2 machine, there was a slight improvement which is possibly
due to pages from other nodes trapped on the test node before starting
the run. I did not investigate further.
This patch shrinks the quicklist based upon free memory on the node
instead of the high/low water marks. I have written it to enable
preemption periodically and recalculate the amount to shrink every time
we have freed enough pages that the quicklist size should have grown.
I rescan the nodes zones each pass because other processess may be
draining node memory at the same time as we are adding.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Hugh Dickins
Bob Picco
Peter Chubb
David Mosberger-Tang
Tony Luck
Robin Holt
Linus Torvalds