The patch titled
mm: fix mbind vma merge problem
has been added to the -mm tree. Its filename is
mm-fix-mbind-vma-merge-problem.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: fix mbind vma merge problem
From: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Strangely, current mbind() doesn't merge vma with neighbor vma although it's possible.
Unfortunately, many vma can reduce performance...
This patch fixes it.
reproduced program
----------------------------------------------------------------
#include <numaif.h>
#include <numa.h>
#include <sys/mman.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
static unsigned long pagesize;
int main(int argc, char** argv)
{
void* addr;
int ch;
int node;
struct bitmask *nmask = numa_allocate_nodemask();
int err;
int node_set = 0;
char buf[128];
while ((ch = getopt(argc, argv, "n:")) != -1){
switch (ch){
case 'n':
node = strtol(optarg, NULL, 0);
numa_bitmask_setbit(nmask, node);
node_set = 1;
break;
default:
;
}
}
argc -= optind;
argv += optind;
if (!node_set)
numa_bitmask_setbit(nmask, 0);
pagesize = getpagesize();
addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, 0, 0);
if (addr == MAP_FAILED)
perror("mmap "), exit(1);
fprintf(stderr, "pid = %d \n" "addr = %p\n", getpid(), addr);
/* make page populate */
memset(addr, 0, pagesize*3);
/* first mbind */
err = mbind(addr+pagesize, pagesize, MPOL_BIND, nmask->maskp,
nmask->size, MPOL_MF_MOVE_ALL);
if (err)
error("mbind1 ");
/* second mbind */
err = mbind(addr, pagesize*3, MPOL_DEFAULT, NULL, 0, 0);
if (err)
error("mbind2 ");
sprintf(buf, "cat /proc/%d/maps", getpid());
system(buf);
return 0;
}
----------------------------------------------------------------
result without this patch
addr = 0x7fe26ef09000
[snip]
7fe26ef09000-7fe26ef0a000 rw-p 00000000 00:00 0
7fe26ef0a000-7fe26ef0b000 rw-p 00000000 00:00 0
7fe26ef0b000-7fe26ef0c000 rw-p 00000000 00:00 0
7fe26ef0c000-7fe26ef0d000 rw-p 00000000 00:00 0
=> 0x7fe26ef09000-0x7fe26ef0c000 have three vmas.
result with this patch
addr = 0x7fc9ebc76000
[snip]
7fc9ebc76000-7fc9ebc7a000 rw-p 00000000 00:00 0
7fffbe690000-7fffbe6a5000 rw-p 00000000 00:00 0 [stack]
=> 0x7fc9ebc76000-0x7fc9ebc7a000 have only one vma.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 51 +++++++++++++++++++++++++++++++++++------------
1 file changed, 38 insertions(+), 13 deletions(-)
diff -puN mm/mempolicy.c~mm-fix-mbind-vma-merge-problem mm/mempolicy.c
--- a/mm/mempolicy.c~mm-fix-mbind-vma-merge-problem
+++ a/mm/mempolicy.c
@@ -563,24 +563,49 @@ static int policy_vma(struct vm_area_str
}
/* Step 2: apply policy to a range and do splits. */
-static int mbind_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end, struct mempolicy *new)
+static int mbind_range(struct mm_struct *mm, unsigned long start,
+ unsigned long end, struct mempolicy *new_pol)
{
struct vm_area_struct *next;
- int err;
+ struct vm_area_struct *prev;
+ struct vm_area_struct *vma;
+ int err = 0;
+ unsigned long vmstart;
+ unsigned long vmend;
- err = 0;
- for (; vma && vma->vm_start < end; vma = next) {
+ vma = find_vma_prev(mm, start, &prev);
+ if (!vma || vma->vm_start > start)
+ return -EFAULT;
+
+ for (; vma && vma->vm_start < end; prev = vma, vma = next) {
next = vma->vm_next;
- if (vma->vm_start < start)
- err = split_vma(vma->vm_mm, vma, start, 1);
- if (!err && vma->vm_end > end)
- err = split_vma(vma->vm_mm, vma, end, 0);
- if (!err)
- err = policy_vma(vma, new);
+ vmstart = max(start, vma->vm_start);
+ vmend = min(end, vma->vm_end);
+
+ prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
+ vma->anon_vma, vma->vm_file, vma->vm_pgoff,
+ new_pol);
+ if (prev) {
+ vma = prev;
+ next = vma->vm_next;
+ continue;
+ }
+ if (vma->vm_start != vmstart) {
+ err = split_vma(vma->vm_mm, vma, vmstart, 1);
+ if (err)
+ goto out;
+ }
+ if (vma->vm_end != vmend) {
+ err = split_vma(vma->vm_mm, vma, vmend, 0);
+ if (err)
+ goto out;
+ }
+ err = policy_vma(vma, new_pol);
if (err)
- break;
+ goto out;
}
+
+ out:
return err;
}
@@ -1047,7 +1072,7 @@ static long do_mbind(unsigned long start
if (!IS_ERR(vma)) {
int nr_failed = 0;
- err = mbind_range(vma, start, end, new);
+ err = mbind_range(mm, start, end, new);
if (!list_empty(&pagelist))
nr_failed = migrate_pages(&pagelist, new_vma_page,
_
Patches currently in -mm which might be from kosaki.motohiro@xxxxxxxxxxxxxx are
linux-next.patch
page-allocator-fix-update-nr_free_pages-only-as-necessary.patch
mm-page_alloc-fix-the-range-check-for-backward-merging.patch
vmscan-kswapd-dont-retry-balance_pgdat-if-all-zones-are-unreclaimable.patch
mm-introduce-dump_page-and-print-symbolic-flag-names.patch
page-allocator-reduce-fragmentation-in-buddy-allocator-by-adding-buddies-that-are-merging-to-the-tail-of-the-free-lists.patch
mlock_vma_pages_range-never-return-negative-value.patch
mlock_vma_pages_range-only-return-success-or-failure.patch
vmscan-check-high-watermark-after-shrink-zone.patch
vmscan-check-high-watermark-after-shrink-zone-fix.patch
vmscan-get_scan_ratio-cleanup.patch
vmstat-add-anon_scan_ratio-field-to-zoneinfo.patch
memcg-add-anon_scan_ratio-to-memorystat-file.patch
mm-lockdep-annotate-reclaim-context-to-zone-reclaim-too.patch
mm-page_allocc-remove-duplicate-call-to-trace_mm_page_free_direct.patch
mm-page_allocc-adjust-a-call-site-to-trace_mm_page_free_direct.patch
mm-remove-function-free_hot_page.patch
mm-restore-zone-all_unreclaimable-to-independence-word.patch
mm-fix-mbind-vma-merge-problem.patch
prctl-add-pr_set_proctitle_area-option-for-prctl.patch
mm-pass-mm-flags-as-a-coredump-parameter-for-consistency.patch
memcg-move-charges-of-anonymous-swap-fix-2.patch
fs-symlink-write_begin-allocation-context-fix-reiser4-fix.patch
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