Commit a2e29467 authored by Roman Gushchin's avatar Roman Gushchin Committed by Zheng Zengkai
Browse files

mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors

stable inclusion
from stable-v6.6.3
commit 572d3e8b57f17a3b6bc738dd64730ef7ce85676b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=572d3e8b57f17a3b6bc738dd64730ef7ce85676b

--------------------------------

commit 24948e3b7b12e0031a6edb4f49bbb9fb2ad1e4e9 upstream.

Objcg vectors attached to slab pages to store slab object ownership
information are allocated using gfp flags for the original slab
allocation.  Depending on slab page order and the size of slab objects,
objcg vector can take several pages.

If the original allocation was done with the __GFP_NOFAIL flag, it
triggered a warning in the page allocation code.  Indeed, order > 1 pages
should not been allocated with the __GFP_NOFAIL flag.

Fix this by simply dropping the __GFP_NOFAIL flag when allocating the
objcg vector.  It effectively allows to skip the accounting of a single
slab object under a heavy memory pressure.

An alternative would be to implement the mechanism to fallback to order-0
allocations for accounting metadata, which is also not perfect because it
will increase performance penalty and memory footprint of the kernel
memory accounting under memory pressure.

Link: https://lkml.kernel.org/r/ZUp8ZFGxwmCx4ZFr@P9FQF9L96D.corp.robot.car


Signed-off-by: default avatarRoman Gushchin <roman.gushchin@linux.dev>
Reported-by: default avatarChristoph Lameter <cl@linux.com>
Closes: https://lkml.kernel.org/r/6b42243e-f197-600a-5d22-56bd728a5ad8@gentwo.org


Acked-by: default avatarShakeel Butt <shakeelb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 48268720
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