The patch titled
Subject: mm: shmem: use proper gfp flags for shmem_writepage()
has been added to the -mm tree. Its filename is
mm-shmem-use-proper-gfp-flags-for-shmem_writepage.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-shmem-use-proper-gfp-flags-for-shmem_writepage.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-shmem-use-proper-gfp-flags-for-shmem_writepage.patch
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------------------------------------------------------
From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Subject: mm: shmem: use proper gfp flags for shmem_writepage()
The shmem_writepage() uses GFP_ATOMIC to allocate swap cache. GFP_ATOMIC
used to mean __GFP_HIGH, but now it means __GFP_HIGH | __GFP_ATOMIC |
__GFP_KSWAPD_RECLAIM. However, shmem_writepage() should write out to swap
only in response to memory pressure, so __GFP_KSWAPD_RECLAIM looks useless
since the caller may be kswapd itself or in direct reclaim already.
In addition, XArray node allocations from PF_MEMALLOC contexts could
completely exhaust the page allocator, __GFP_NOMEMALLOC stops emergency
reserves from being allocated.
Here just copy the gfp flags used by add_to_swap().
Hugh: "a cleanup to make the two calls look the same when they don't need
to be different (whereas the call from __read_swap_cache_async() rightly
uses a lower priority gfp)".
Link: http://lkml.kernel.org/r/1572991351-86061-1-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/shmem.c~mm-shmem-use-proper-gfp-flags-for-shmem_writepage
+++ a/mm/shmem.c
@@ -1369,7 +1369,8 @@ static int shmem_writepage(struct page *
if (list_empty(&info->swaplist))
list_add(&info->swaplist, &shmem_swaplist);
- if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
+ if (add_to_swap_cache(page, swap,
+ __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN) == 0) {
spin_lock_irq(&info->lock);
shmem_recalc_inode(inode);
info->swapped++;
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxxxxxxxxx are
mm-mempolicy-fix-the-wrong-return-value-and-potential-pages-leak-of-mbind.patch
mm-rmap-use-vm_bug_on-in-__page_check_anon_rmap.patch
mm-vmscan-remove-unused-scan_control-parameter-from-pageout.patch
mm-shmem-use-proper-gfp-flags-for-shmem_writepage.patch
