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  1. 22 6月, 2005 12 次提交
    • C
      [PATCH] mmap topdown fix for large stack limit, large allocation · 73219d17
      由 Chris Wright 提交于 
      The topdown changes in 2.6.12-rc1 can cause large allocations with large
stack limit to fail, despite there being space available.  The
mmap_base-len is only valid when len >= mmap_base.  However, nothing in
topdown allocator checks this.  It's only (now) caught at higher level,
which will cause allocation to simply fail.  The following change restores
the fallback to bottom-up path, which will allow large allocations with
large stack limit to potentially still succeed.
Signed-off-by: NChris Wright <chrisw@osdl.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      73219d17
    • W
      [PATCH] Avoiding mmap fragmentation · 1363c3cd
      由 Wolfgang Wander 提交于 
      Ingo recently introduced a great speedup for allocating new mmaps using the
free_area_cache pointer which boosts the specweb SSL benchmark by 4-5% and
causes huge performance increases in thread creation.

The downside of this patch is that it does lead to fragmentation in the
mmap-ed areas (visible via /proc/self/maps), such that some applications
that work fine under 2.4 kernels quickly run out of memory on any 2.6
kernel.

The problem is twofold:

  1) the free_area_cache is used to continue a search for memory where
     the last search ended.  Before the change new areas were always
     searched from the base address on.

     So now new small areas are cluttering holes of all sizes
     throughout the whole mmap-able region whereas before small holes
     tended to close holes near the base leaving holes far from the base
     large and available for larger requests.

  2) the free_area_cache also is set to the location of the last
     munmap-ed area so in scenarios where we allocate e.g.  five regions of
     1K each, then free regions 4 2 3 in this order the next request for 1K
     will be placed in the position of the old region 3, whereas before we
     appended it to the still active region 1, placing it at the location
     of the old region 2.  Before we had 1 free region of 2K, now we only
     get two free regions of 1K -> fragmentation.

The patch addresses thes issues by introducing yet another cache descriptor
cached_hole_size that contains the largest known hole size below the
current free_area_cache.  If a new request comes in the size is compared
against the cached_hole_size and if the request can be filled with a hole
below free_area_cache the search is started from the base instead.

The results look promising: Whereas 2.6.12-rc4 fragments quickly and my
(earlier posted) leakme.c test program terminates after 50000+ iterations
with 96 distinct and fragmented maps in /proc/self/maps it performs nicely
(as expected) with thread creation, Ingo's test_str02 with 20000 threads
requires 0.7s system time.

Taking out Ingo's patch (un-patch available per request) by basically
deleting all mentions of free_area_cache from the kernel and starting the
search for new memory always at the respective bases we observe: leakme
terminates successfully with 11 distinctive hardly fragmented areas in
/proc/self/maps but thread creating is gringdingly slow: 30+s(!) system
time for Ingo's test_str02 with 20000 threads.

Now - drumroll ;-) the appended patch works fine with leakme: it ends with
only 7 distinct areas in /proc/self/maps and also thread creation seems
sufficiently fast with 0.71s for 20000 threads.
Signed-off-by: NWolfgang Wander <wwc@rentec.com>
Credit-to: "Richard Purdie" <rpurdie@rpsys.net>
Signed-off-by: NKen Chen <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu> (partly)
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      1363c3cd
    • C
      [PATCH] node local per-cpu-pages · e7c8d5c9
      由 Christoph Lameter 提交于 
      This patch modifies the way pagesets in struct zone are managed.

Each zone has a per-cpu array of pagesets.  So any particular CPU has some
memory in each zone structure which belongs to itself.  Even if that CPU is
not local to that zone.

So the patch relocates the pagesets for each cpu to the node that is nearest
to the cpu instead of allocating the pagesets in the (possibly remote) target
zone.  This means that the operations to manage pages on remote zone can be
done with information available locally.

We play a macro trick so that non-NUMA pmachines avoid the additional
pointer chase on the page allocator fastpath.

AIM7 benchmark on a 32 CPU SGI Altix

w/o patches:
Tasks    jobs/min  jti  jobs/min/task      real       cpu
    1      484.68  100       484.6769     12.01      1.97   Fri Mar 25 11:01:42 2005
  100    27140.46   89       271.4046     21.44    148.71   Fri Mar 25 11:02:04 2005
  200    30792.02   82       153.9601     37.80    296.72   Fri Mar 25 11:02:42 2005
  300    32209.27   81       107.3642     54.21    451.34   Fri Mar 25 11:03:37 2005
  400    34962.83   78        87.4071     66.59    588.97   Fri Mar 25 11:04:44 2005
  500    31676.92   75        63.3538     91.87    742.71   Fri Mar 25 11:06:16 2005
  600    36032.69   73        60.0545     96.91    885.44   Fri Mar 25 11:07:54 2005
  700    35540.43   77        50.7720    114.63   1024.28   Fri Mar 25 11:09:49 2005
  800    33906.70   74        42.3834    137.32   1181.65   Fri Mar 25 11:12:06 2005
  900    34120.67   73        37.9119    153.51   1325.26   Fri Mar 25 11:14:41 2005
 1000    34802.37   74        34.8024    167.23   1465.26   Fri Mar 25 11:17:28 2005

with slab API changes and pageset patch:

Tasks    jobs/min  jti  jobs/min/task      real       cpu
    1      485.00  100       485.0000     12.00      1.96   Fri Mar 25 11:46:18 2005
  100    28000.96   89       280.0096     20.79    150.45   Fri Mar 25 11:46:39 2005
  200    32285.80   79       161.4290     36.05    293.37   Fri Mar 25 11:47:16 2005
  300    40424.15   84       134.7472     43.19    438.42   Fri Mar 25 11:47:59 2005
  400    39155.01   79        97.8875     59.46    590.05   Fri Mar 25 11:48:59 2005
  500    37881.25   82        75.7625     76.82    730.19   Fri Mar 25 11:50:16 2005
  600    39083.14   78        65.1386     89.35    872.79   Fri Mar 25 11:51:46 2005
  700    38627.83   77        55.1826    105.47   1022.46   Fri Mar 25 11:53:32 2005
  800    39631.94   78        49.5399    117.48   1169.94   Fri Mar 25 11:55:30 2005
  900    36903.70   79        41.0041    141.94   1310.78   Fri Mar 25 11:57:53 2005
 1000    36201.23   77        36.2012    160.77   1458.31   Fri Mar 25 12:00:34 2005
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NShobhit Dayal <shobhit@calsoftinc.com>
Signed-off-by: NShai Fultheim <Shai@Scalex86.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      e7c8d5c9
    • D
      [PATCH] Hugepage consolidation · 63551ae0
      由 David Gibson 提交于 
      A lot of the code in arch/*/mm/hugetlbpage.c is quite similar.  This patch
attempts to consolidate a lot of the code across the arch's, putting the
combined version in mm/hugetlb.c.  There are a couple of uglyish hacks in
order to covert all the hugepage archs, but the result is a very large
reduction in the total amount of code.  It also means things like hugepage
lazy allocation could be implemented in one place, instead of six.

Tested, at least a little, on ppc64, i386 and x86_64.

Notes:
	- this patch changes the meaning of set_huge_pte() to be more
	  analagous to set_pte()
	- does SH4 need s special huge_ptep_get_and_clear()??
Acked-by: NWilliam Lee Irwin <wli@holomorphy.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      63551ae0
    • M
      [PATCH] VM: rate limit early reclaim · 1e7e5a90
      由 Martin Hicks 提交于 
      When early zone reclaim is turned on the LRU is scanned more frequently when a
zone is low on memory.  This limits when the zone reclaim can be called by
skipping the scan if another thread (either via kswapd or sync reclaim) is
already reclaiming from the zone.
Signed-off-by: NMartin Hicks <mort@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      1e7e5a90
    • M
      [PATCH] VM: add __GFP_NORECLAIM · 0c35bbad
      由 Martin Hicks 提交于 
      When using the early zone reclaim, it was noticed that allocating new pages
that should be spread across the whole system caused eviction of local pages.

This adds a new GFP flag to prevent early reclaim from happening during
certain allocation attempts.  The example that is implemented here is for page
cache pages.  We want page cache pages to be spread across the whole system,
and we don't want page cache pages to evict other pages to get local memory.
Signed-off-by: NMartin Hicks <mort@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      0c35bbad
    • M
      [PATCH] VM: early zone reclaim · 753ee728
      由 Martin Hicks 提交于 
      This is the core of the (much simplified) early reclaim.  The goal of this
patch is to reclaim some easily-freed pages from a zone before falling back
onto another zone.

One of the major uses of this is NUMA machines.  With the default allocator
behavior the allocator would look for memory in another zone, which might be
off-node, before trying to reclaim from the current zone.

This adds a zone tuneable to enable early zone reclaim.  It is selected on a
per-zone basis and is turned on/off via syscall.

Adding some extra throttling on the reclaim was also required (patch
4/4).  Without the machine would grind to a crawl when doing a "make -j"
kernel build.  Even with this patch the System Time is higher on
average, but it seems tolerable.  Here are some numbers for kernbench
runs on a 2-node, 4cpu, 8Gig RAM Altix in the "make -j" run:

			wall  user   sys   %cpu  ctx sw.  sleeps
			----  ----   ---   ----   ------  ------
No patch		1009  1384   847   258   298170   504402
w/patch, no reclaim     880   1376   667   288   254064   396745
w/patch & reclaim       1079  1385   926   252   291625   548873

These numbers are the average of 2 runs of 3 "make -j" runs done right
after system boot.  Run-to-run variability for "make -j" is huge, so
these numbers aren't terribly useful except to seee that with reclaim
the benchmark still finishes in a reasonable amount of time.

I also looked at the NUMA hit/miss stats for the "make -j" runs and the
reclaim doesn't make any difference when the machine is thrashing away.

Doing a "make -j8" on a single node that is filled with page cache pages
takes 700 seconds with reclaim turned on and 735 seconds without reclaim
(due to remote memory accesses).

The simple zone_reclaim syscall program is at
http://www.bork.org/~mort/sgi/zone_reclaim.cSigned-off-by: NMartin Hicks <mort@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      753ee728
    • M
      [PATCH] VM: add may_swap flag to scan_control · bfbb38fb
      由 Martin Hicks 提交于 
      Here's the next round of these patches.  These are totally different in
an attempt to meet the "simpler" request after the last patches.  For
reference the earlier threads are:

http://marc.theaimsgroup.com/?l=linux-kernel&m=110839604924587&w=2
http://marc.theaimsgroup.com/?l=linux-mm&m=111461480721249&w=2

This set of patches replaces my other vm- patches that are currently in
-mm.  So they're against 2.6.12-rc5-mm1 about half way through the -mm
patchset.

As I said already this patch is a lot simpler.  The reclaim is turned on
or off on a per-zone basis using a syscall.  I haven't tested the x86
syscall, so it might be wrong.  It uses the existing reclaim/pageout
code with the small addition of a may_swap flag to scan_control
(patch 1/4).

I also added __GFP_NORECLAIM (patch 3/4) so that certain allocation
types can be flagged to never cause reclaim.  This was a deficiency
that was in all of my earlier patch sets.  Previously, doing a big
buffered read would fill one zone with page cache and then start to
reclaim from that same zone, leaving the other zones untouched.

Adding some extra throttling on the reclaim was also required (patch
4/4).  Without the machine would grind to a crawl when doing a "make -j"
kernel build.  Even with this patch the System Time is higher on
average, but it seems tolerable.  Here are some numbers for kernbench
runs on a 2-node, 4cpu, 8Gig RAM Altix in the "make -j" run:

			wall  user   sys   %cpu  ctx sw.  sleeps
			----  ----   ---   ----   ------  ------
No patch		1009  1384   847   258   298170   504402
w/patch, no reclaim     880   1376   667   288   254064   396745
w/patch & reclaim       1079  1385   926   252   291625   548873

These numbers are the average of 2 runs of 3 "make -j" runs done right
after system boot.  Run-to-run variability for "make -j" is huge, so
these numbers aren't terribly useful except to seee that with reclaim
the benchmark still finishes in a reasonable amount of time.

I also looked at the NUMA hit/miss stats for the "make -j" runs and the
reclaim doesn't make any difference when the machine is thrashing away.

Doing a "make -j8" on a single node that is filled with page cache pages
takes 700 seconds with reclaim turned on and 735 seconds without reclaim
(due to remote memory accesses).

The simple zone_reclaim syscall program is at
http://www.bork.org/~mort/sgi/zone_reclaim.c

This patch:

This adds an extra switch to the scan_control struct.  It simply lets the
reclaim code know if its allowed to swap pages out.

This was required for a simple per-zone reclaimer.  Without this addition
pages would be swapped out as soon as a zone ran out of memory and the early
reclaim kicked in.
Signed-off-by: NMartin Hicks <mort@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      bfbb38fb
    • N
      [PATCH] mm: add /proc/zoneinfo · 295ab934
      由 Nikita Danilov 提交于 
      Add /proc/zoneinfo file to display information about memory zones.  Useful
to analyze VM behaviour.
Signed-off-by: NNikita Danilov <nikita@clusterfs.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      295ab934
    • P
      [PATCH] madvise: merge the maps · 05b74384
      由 Prasanna Meda 提交于 
      This attempts to merge back the split maps.  This code is mostly copied
from Chrisw's mlock merging from post 2.6.11 trees.  The only difference is
in munmapped_error handling.  Also passed prev to willneed/dontneed,
eventhogh they do not handle it now, since I felt it will be cleaner,
instead of handling prev in madvise_vma in some cases and in subfunction in
some cases.
Signed-off-by: NPrasanna Meda <pmeda@akamai.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      05b74384
    • P
      [PATCH] madvise: do not split the maps · e798c6e8
      由 Prasanna Meda 提交于 
      This attempts to avoid splittings when it is not needed, that is when
vm_flags are same as new flags.  The idea is from the <2.6.11 mlock_fixup
and others.  This will provide base for the next madvise merging patch.
Signed-off-by: NPrasanna Meda <pmeda@akamai.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      e798c6e8
    • A
      [PATCH] vmscan: notice slab shrinking · b15e0905
      由 akpm@osdl.org 提交于 
      Fix a problem identified by Andrea Arcangeli <andrea@suse.de>

kswapd will set a zone into all_unreclaimable state if it sees that we're not
successfully reclaiming LRU pages.  But that fails to notice that we're
successfully reclaiming slab obects, so we can set all_unreclaimable too soon.

So change shrink_slab() to return a success indication if it actually
reclaimed some objects, and don't assume that the zone is all_unreclaimable if
that is true.  This means that we won't enter all_unreclaimable state if we
are successfully freeing slab objects but we're not yet actually freeing slab
pages, due to internal fragmentation.

(hm, this has a shortcoming.  We could be successfully freeing ZONE_NORMAL
slab objects while being really oom on ZONE_DMA.  If that happens then kswapd
might burn a lot of CPU.  But given that there might be some slab objects in
ZONE_DMA, perhaps that is appropriate.)
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b15e0905
  3. 19 6月, 2005 1 次提交
  5. 07 6月, 2005 1 次提交
  7. 25 5月, 2005 1 次提交
    • W
      [PATCH] try_to_unmap_cluster() passes out-of-bounds pte to pte_unmap() · cafdd8ba
      由 William Lee Irwin III 提交于 
      try_to_unmap_cluster() does:
        for (pte = pte_offset_map(pmd, address);
                        address < end; pte++, address += PAGE_SIZE) {
		...
	}

	pte_unmap(pte);

It may take a little staring to notice, but pte can actually fall off the
end of the pte page in this iteration, which makes life difficult for
kmap_atomic() and the users not expecting it to BUG().  Of course, we're
somewhat lucky in that arithmetic elsewhere in the function guarantees that
at least one iteration is made, lest this force larger rearrangements to be
made.  This issue and patch also apply to non-mm mainline and with trivial
adjustments, at least two related kernels.

Discovered during internal testing at Oracle.
Signed-off-by: NWilliam Irwin <wli@holomorphy.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      cafdd8ba
  9. 22 5月, 2005 1 次提交
    • S
      [PATCH] fix for __generic_file_aio_read() to return 0 on EOF · b5c44c21
      由 Suparna Bhattacharya 提交于 
      I came across the following problem while running ltp-aiodio testcases from
ltp-full-20050405 on linux-2.6.12-rc3-mm3.  I tried running the tests with
EXT3 as well as JFS filesystems.

One or two fsx-linux testcases were hung after some time.  These testcases
were hanging at wait_for_all_aios().

Debugging shows that there were some iocbs which were not getting completed
eventhough the last retry for those returned -EIOCBQUEUED.  Also all such
pending iocbs represented READ operation.

Further debugging revealed that all such iocbs hit EOF in the DIO layer.
To be more precise, the "pos" from which they were trying to read was
greater than the "size" of the file.  So the generic_file_direct_IO
returned 0.

This happens rarely as there is already a check in
__generic_file_aio_read(), for whether "pos" < "size" before calling direct
IO routine.

>size = i_size_read(inode);
>if (pos < size) {
>	  retval = generic_file_direct_IO(READ, iocb,
>                               iov, pos, nr_segs);

But for READ, we are taking the inode->i_sem only in the DIO layer.  So it
is possible that some other process can change the size of the file before
we take the i_sem.  In such a case ( when "pos" > "size"), the
__generic_file_aio_read() would return -EIOCBQUEUED even though there were
no I/O requests submitted by the DIO layer.  This would cause the AIO layer
to expect aio_complete() for THE iocb, which doesnot happen.  And thus the
test hangs forever, waiting for an I/O completion, where there are no
requests submitted at all.

The following patch makes __generic_file_aio_read() return 0 (instead of
returning -EIOCBQUEUED), on getting 0 from generic_file_direct_IO(), so
that the AIO layer does the aio_complete().

Testing:

I have tested the patch on a SMP machine(with 2 Pentium 4 (HT)) running
linux-2.6.12-rc3-mm3.  I ran the ltp-aiodio testcases and none of the
fsx-linux tests hung.  Also the aio-stress tests ran without any problem.
Signed-off-by: NSuzuki K P <suzuki@in.ibm.com>
Signed-off-by: NSuparna Bhattacharya <suparna@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b5c44c21
  11. 21 5月, 2005 1 次提交
  13. 20 5月, 2005 1 次提交
    • L
      Fix get_unmapped_area sanity tests · 07ab67c8
      由 Linus Torvalds 提交于 
      As noted by Chris Wright, we need to do the full range of tests regardless
of whether MAP_FIXED is set or not, so re-organize get_unmapped_area()
slightly to do the sanity checks unconditionally.
      07ab67c8
  15. 19 5月, 2005 1 次提交
    • L
      [PATCH] prevent NULL mmap in topdown model · 49a43876
      由 Linus Torvalds 提交于 
      Prevent the topdown allocator from allocating mmap areas all the way
down to address zero.

We still allow a MAP_FIXED mapping of page 0 (needed for various things,
ranging from Wine and DOSEMU to people who want to allow speculative
loads off a NULL pointer).

Tested by Chris Wright.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      49a43876
  17. 17 5月, 2005 5 次提交
  19. 06 5月, 2005 1 次提交
  21. 04 5月, 2005 1 次提交
  23. 01 5月, 2005 14 次提交