linux.git/mm/page_alloc.c, branch v5.13

mm/page_alloc: do bulk array bounds check after checking populated elements

2021-06-25T02:40:54+00:00

Dan Carpenter reported the following

  The patch 0f87d9d30f21: "mm/page_alloc: add an array-based interface
  to the bulk page allocator" from Apr 29, 2021, leads to the following
  static checker warning:

        mm/page_alloc.c:5338 __alloc_pages_bulk()
        warn: potentially one past the end of array 'page_array[nr_populated]'

The problem can occur if an array is passed in that is fully populated.
That potentially ends up allocating a single page and storing it past
the end of the array.  This patch returns 0 if the array is fully
populated.

Link: https://lkml.kernel.org/r/20210618125102.GU30378@techsingularity.net
Fixes: 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the bulk page allocator")
Signed-off-by: Mel Gorman 
Reported-by: Dan Carpenter 
Cc: Jesper Dangaard Brouer 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/page_alloc: __alloc_pages_bulk(): do bounds check before accessing array

2021-06-25T02:40:54+00:00

In the event that somebody would call this with an already fully
populated page_array, the last loop iteration would do an access beyond
the end of page_array.

It's of course extremely unlikely that would ever be done, but this
triggers my internal static analyzer.  Also, if it really is not
supposed to be invoked this way (i.e., with no NULL entries in
page_array), the nr_populated
Acked-by: Mel Gorman 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/page_alloc: fix counting of free pages after take off from buddy

2021-06-05T15:58:11+00:00

Recently we found that there is a lot MemFree left in /proc/meminfo
after do a lot of pages soft offline, it's not quite correct.

Before Oscar's rework of soft offline for free pages [1], if we soft
offline free pages, these pages are left in buddy with HWPoison flag,
and NR_FREE_PAGES is not updated immediately.  So the difference between
NR_FREE_PAGES and real number of available free pages is also even big
at the beginning.

However, with the workload running, when we catch HWPoison page in any
alloc functions subsequently, we will remove it from buddy, meanwhile
update the NR_FREE_PAGES and try again, so the NR_FREE_PAGES will get
more and more closer to the real number of available free pages.
(regardless of unpoison_memory())

Now, for offline free pages, after a successful call
take_page_off_buddy(), the page is no longer belong to buddy allocator,
and will not be used any more, but we missed accounting NR_FREE_PAGES in
this situation, and there is no chance to be updated later.

Do update in take_page_off_buddy() like rmqueue() does, but avoid double
counting if some one already set_migratetype_isolate() on the page.

[1]: commit 06be6ff3d2ec ("mm,hwpoison: rework soft offline for free pages")

Link: https://lkml.kernel.org/r/20210526075247.11130-1-dinghui@sangfor.com.cn
Fixes: 06be6ff3d2ec ("mm,hwpoison: rework soft offline for free pages")
Signed-off-by: Ding Hui 
Suggested-by: Naoya Horiguchi 
Reviewed-by: Oscar Salvador 
Acked-by: David Hildenbrand 
Acked-by: Naoya Horiguchi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix typos in comments

2021-05-07T07:26:35+00:00

succed -> succeed in mm/hugetlb.c
wil -> will in mm/mempolicy.c
wit -> with in mm/page_alloc.c
Retruns -> Returns in mm/page_vma_mapped.c
confict -> conflict in mm/secretmem.c
No functionality changed.

Link: https://lkml.kernel.org/r/20210408140027.60623-1-lujialin4@huawei.com
Signed-off-by: Lu Jialin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix typos in comments

2021-05-07T07:26:35+00:00

Fix ~94 single-word typos in locking code comments, plus a few
very obvious grammar mistakes.

Link: https://lkml.kernel.org/r/20210322212624.GA1963421@gmail.com
Link: https://lore.kernel.org/r/20210322205203.GB1959563@gmail.com
Signed-off-by: Ingo Molnar 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: Randy Dunlap 
Cc: Bhaskar Chowdhury 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/mempool: minor coding style tweaks

2021-05-05T18:27:27+00:00

Various coding style tweaks to various files under mm/

[daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn
[daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks]
  Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn

Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn
Signed-off-by: Zhiyuan Dai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory_hotplug: remove broken locking of zone PCP structures during hot remove

2021-05-05T18:27:26+00:00

zone_pcp_reset allegedly protects against a race with drain_pages using
local_irq_save but this is bogus.  local_irq_save only operates on the
local CPU.  If memory hotplug is running on CPU A and drain_pages is
running on CPU B, disabling IRQs on CPU A does not affect CPU B and
offers no protection.

This patch deletes IRQ disable/enable on the grounds that IRQs protect
nothing and assumes the existing hotplug paths guarantees the PCP cannot
be used after zone_pcp_enable().  That should be the case already
because all the pages have been freed and there is no page to put on the
PCP lists.

Link: https://lkml.kernel.org/r/20210412090346.GQ3697@techsingularity.net
Signed-off-by: Mel Gorman 
Acked-by: Michal Hocko 
Reviewed-by: Oscar Salvador 
Cc: "Michael S. Tsirkin" 
Cc: Vlastimil Babka 
Cc: Alexander Duyck 
Cc: Minchan Kim 
Cc: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: honor PF_MEMALLOC_PIN for all movable pages

2021-05-05T18:27:26+00:00

PF_MEMALLOC_PIN is only honored for CMA pages, extend this flag to work
for any allocations from ZONE_MOVABLE by removing __GFP_MOVABLE from
gfp_mask when this flag is passed in the current context.

Add is_pinnable_page() to return true if page is in a pinnable page.  A
pinnable page is not in ZONE_MOVABLE and not of MIGRATE_CMA type.

Link: https://lkml.kernel.org/r/20210215161349.246722-8-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin 
Acked-by: Michal Hocko 
Cc: Dan Williams 
Cc: David Hildenbrand 
Cc: David Rientjes 
Cc: Ingo Molnar 
Cc: Ira Weiny 
Cc: James Morris 
Cc: Jason Gunthorpe 
Cc: Jason Gunthorpe 
Cc: John Hubbard 
Cc: Joonsoo Kim 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Mike Kravetz 
Cc: Oscar Salvador 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Steven Rostedt (VMware) 
Cc: Tyler Hicks 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: apply per-task gfp constraints in fast path

2021-05-05T18:27:26+00:00

Function current_gfp_context() is called after fast path.  However, soon
we will add more constraints which will also limit zones based on
context.  Move this call into fast path, and apply the correct
constraints for all allocations.

Also update .reclaim_idx based on value returned by
current_gfp_context() because it soon will modify the allowed zones.

Note:
With this patch we will do one extra current->flags load during fast path,
but we already load current->flags in fast-path:

__alloc_pages()
 prepare_alloc_pages()
  current_alloc_flags(gfp_mask, *alloc_flags);

Later, when we add the zone constrain logic to current_gfp_context() we
will be able to remove current->flags load from current_alloc_flags, and
therefore return fast-path to the current performance level.

Link: https://lkml.kernel.org/r/20210215161349.246722-7-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin 
Suggested-by: Michal Hocko 
Acked-by: Michal Hocko 
Cc: Dan Williams 
Cc: David Hildenbrand 
Cc: David Rientjes 
Cc: Ingo Molnar 
Cc: Ira Weiny 
Cc: James Morris 
Cc: Jason Gunthorpe 
Cc: Jason Gunthorpe 
Cc: John Hubbard 
Cc: Joonsoo Kim 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Mike Kravetz 
Cc: Oscar Salvador 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Steven Rostedt (VMware) 
Cc: Tyler Hicks 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN

2021-05-05T18:27:26+00:00

PF_MEMALLOC_NOCMA is used ot guarantee that the allocator will not
return pages that might belong to CMA region.  This is currently used
for long term gup to make sure that such pins are not going to be done
on any CMA pages.

When PF_MEMALLOC_NOCMA has been introduced we haven't realized that it
is focusing on CMA pages too much and that there is larger class of
pages that need the same treatment.  MOVABLE zone cannot contain any
long term pins as well so it makes sense to reuse and redefine this flag
for that usecase as well.  Rename the flag to PF_MEMALLOC_PIN which
defines an allocation context which can only get pages suitable for
long-term pins.

Also rename: memalloc_nocma_save()/memalloc_nocma_restore to
memalloc_pin_save()/memalloc_pin_restore() and make the new functions
common.

[rppt@linux.ibm.com: fix renaming of PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN]
  Link: https://lkml.kernel.org/r/20210331163816.11517-1-rppt@kernel.org

Link: https://lkml.kernel.org/r/20210215161349.246722-6-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin 
Reviewed-by: John Hubbard 
Acked-by: Michal Hocko 
Signed-off-by: Mike Rapoport 
Cc: Dan Williams 
Cc: David Hildenbrand 
Cc: David Rientjes 
Cc: Ingo Molnar 
Cc: Ira Weiny 
Cc: James Morris 
Cc: Jason Gunthorpe 
Cc: Jason Gunthorpe 
Cc: Joonsoo Kim 
Cc: Matthew Wilcox 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Mike Kravetz 
Cc: Oscar Salvador 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Steven Rostedt (VMware) 
Cc: Tyler Hicks 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds