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mm: page-isolation: skip isolated pageblock in start_isolate_page_range()

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start_isolate_page_range() first isolates the first and the last
pageblocks in the range and ensure pages across range boundaries are split
during isolation.  But it missed the case when the range is <= a pageblock
and the first and the last pageblocks are the same one, so the second
isolate_single_pageblock() will always fail.  To fix it, skip the
pageblock isolation in second isolate_single_pageblock().

Link: https://lkml.kernel.org/r/20220526231531.2404977-1-zi.yan@sent.com
Fixes: 88ee134320 ("mm: fix a potential infinite loop in start_isolate_page_range()")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
  Link: https://lore.kernel.org/linux-mm/ac65adc0-a7e4-cdfe-a0d8-757195b86293@samsung.com/
Reported-by: Michael Walle <michael@walle.cc>
Tested-by: Michael Walle <michael@walle.cc>
  Link: https://lore.kernel.org/linux-mm/8ca048ca8b547e0dd1c95387ee05c23d@walle.cc/
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Eric Ren <renzhengeek@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qian Cai <quic_qiancai@quicinc.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zi Yan 2022-05-26 19:15:30 -04:00 committed by akpm
parent f403f22f8c
commit 9b209e557d
1 changed files with 18 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

26
mm/page_isolation.c
View file

@ -300,7 +300,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
* the in-use page then splitting the free page.
*/
static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
gfp_t gfp_flags, bool isolate_before)
gfp_t gfp_flags, bool isolate_before, bool skip_isolation)
{
unsigned char saved_mt;
unsigned long start_pfn;
@ -327,11 +327,16 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
zone->zone_start_pfn);
saved_mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock), saved_mt, flags,
isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
if (ret)
return ret;
if (skip_isolation)
VM_BUG_ON(!is_migrate_isolate(saved_mt));
else {
ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock), saved_mt, flags,
isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
if (ret)
return ret;
}
/*
* Bail out early when the to-be-isolated pageblock does not form
@ -463,7 +468,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
return 0;
failed:
/* restore the original migratetype */
unset_migratetype_isolate(pfn_to_page(isolate_pageblock), saved_mt);
if (!skip_isolation)
unset_migratetype_isolate(pfn_to_page(isolate_pageblock), saved_mt);
return -EBUSY;
}
@ -522,14 +528,18 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned long isolate_start = ALIGN_DOWN(start_pfn, pageblock_nr_pages);
unsigned long isolate_end = ALIGN(end_pfn, pageblock_nr_pages);
int ret;
bool skip_isolation = false;
/* isolate [isolate_start, isolate_start + pageblock_nr_pages) pageblock */
ret = isolate_single_pageblock(isolate_start, flags, gfp_flags, false);
ret = isolate_single_pageblock(isolate_start, flags, gfp_flags, false, skip_isolation);
if (ret)
return ret;
if (isolate_start == isolate_end - pageblock_nr_pages)
skip_isolation = true;
/* isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock */
ret = isolate_single_pageblock(isolate_end, flags, gfp_flags, true);
ret = isolate_single_pageblock(isolate_end, flags, gfp_flags, true, skip_isolation);
if (ret) {
unset_migratetype_isolate(pfn_to_page(isolate_start), migratetype);
return ret;