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From: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
To: chris.bainbridge@gmail.com, harry.yoo@oracle.com
Cc: vbabka@suse.cz, surenb@google.com, dsterba@suse.cz,
	hao.li@linux.dev, leitao@debian.org, Liam.Howlett@oracle.com,
	zhao1.liu@intel.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux-btrfs@vger.kernel.org,
	regressions@lists.linux.dev, mikhail.v.gavrilov@gmail.com
Subject: Re: [REGRESSION] kswapd0: page allocation failure (bisected to "slab: add sheaves to most caches")
Date: Wed, 25 Feb 2026 06:53:59 +0500	[thread overview]
Message-ID: <20260225015359.1495283-1-mikhail.v.gavrilov@gmail.com> (raw)
In-Reply-To: <aZw2LyOjxMc-c3dl@debian.local>

I can confirm this issue on my system:

  Hardware: ASUS ROG STRIX B650E-I (AMD Ryzen), 64GB RAM
  Storage: btrfs with zram swap
  Kernel: 7.0.0-rc1 (commit 6de23f81a5e0+)

I was seeing the same kswapd0 page allocation failures periodically
under memory pressure with the identical call trace through
alloc_from_pcs -> __pcs_replace_empty_main -> refill_objects ->
allocate_slab.

Chris's btrfs __GFP_NOWARN patch suppresses the btrfs-originated
warnings, but after ~10 hours I hit the same sheaf refill failure
from a different caller -- amdgpu via kmalloc:

  chrome: page allocation failure: order:0,
  mode:0xc0cc0(GFP_KERNEL|__GFP_COMP|__GFP_NOMEMALLOC)

  allocate_slab
  refill_objects
  __pcs_replace_empty_main
  __kmalloc_cache_noprof
  drm_suballoc_new
  amdgpu_sa_bo_new

This confirms the fix needs to be on the slab side as Harry
suggested -- adding __GFP_NOWARN to sheaf refill when there's
a fallback path -- rather than patching individual callers.

Happy to test any slab-side fix.

Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>


  parent reply	other threads:[~2026-02-25  1:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-22 21:36 Chris Bainbridge
2026-02-23  8:41 ` Harry Yoo
2026-02-23 11:12   ` Chris Bainbridge
2026-02-23 11:59     ` Harry Yoo
2026-02-23 20:30       ` David Sterba
2026-02-25  1:53     ` Mikhail Gavrilov [this message]
2026-02-25  2:10       ` Harry Yoo

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