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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771932615; bh=9ttI2emmKns4z1X5WxIR8b0sfR9NkHxRS1s9+gKFrYk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Qdxfz4Kt2XsF/0GMszHnzYd7guNZKIJ6BNgFV3yYQuLu3wxiUKTrn6LfIUc+7E7jj OxG/VASRiWRNCP7s4RPLN40ME9/bKcMHa0THR0Cg6aiCCtU8tApbVBJQBDK9F75qi/ UR/AhqgAtlMks6jlkDXwY6lI5diHP0/ZtEWsVul93qpT4drAhAmdQRX0a/C4oExcAG 8hRjYUW2g0gN5Uv3SLLV+ocvEuJAahcwzwXlXjyMyIA2bkmMuULSJRPmdeS6f220kP v+3AyKEwqqoZoPE4R1ub81xD2rvBSr+c+x2RUK3WbfUXux2PWIvkboqc/z/0vzSVkd n3qVrsi9fZUpw== Message-ID: <5e767065-5536-4b95-8a42-c4be5d31c77f@kernel.org> Date: Tue, 24 Feb 2026 12:30:11 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/slab: pass __GFP_NOWARN to refill_sheaf() if fallback is available Content-Language: en-US To: Chris Bainbridge Cc: Harry Yoo , Vlastimil Babka , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Hao Li , linux-mm@kvack.org References: <20260223133322.16705-1-harry.yoo@oracle.com> From: "Vlastimil Babka (SUSE)" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 5DE82160003 X-Stat-Signature: e7qy4oso4nns7mu1yrr9ny4xzfjgyb1r X-HE-Tag: 1771932616-560247 X-HE-Meta: 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 KpXYg63p Y6+JaunE3O9e+VQWI2F+deNYu9lqNF4zpWiJNyLjx9grJC21nS+RgaI6eV9kfo9xE6Cwc/ighyKRE42Edv3KiPXx35B/B6plnv54wFSGF6Aus/IUfNhtbDkdoc8YeTPVvlZccwq7nfG9I6qbhrMbd757tmcSZMhaZ/1jEvz7FREC/oFFDp/CnqCizmMZUn+Mgf7yvxAxyIfeVkNKkSs2a6zZQgRvK1AjxD6Ui2Qb2ofU0q8locdWJVb81LTYDfPuoib/b5bmtIbFgNNPfKc+YEV/CRpyVOstBhloRiSrgvSNfEcE3slAH2zYUqCYr1lWHpylVc4cJpGlxb99GV+9qA+NcN1voKwfVVLQfoYl34krIB4w6ihiEDKTnov3UaOn8K9VZsf4HqN+BrC3SEPZjjuSaixY53h+4E0B2fC+LIU50ikDcdfVShaHaDlP8eQ6Xgfob X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/23/26 20:46, Chris Bainbridge wrote: > On Mon, Feb 23, 2026 at 05:48:25PM +0100, Vlastimil Babka (SUSE) wrote: >> On 2/23/26 14:33, Harry Yoo wrote: >> > When refill_sheaf() is called, failing to refill the sheaf doesn't >> > necessarily mean the allocation will fail because a fallback path >> > might be available and serve the allocation request. >> > >> > Suppress spurious warnings by passing __GFP_NOWARN along with >> > __GFP_NOMEMALLOC whenever a fallback path is available. >> > >> > When the caller is alloc_full_sheaf() or __pcs_replace_empty_main(), >> > the kernel always falls back to the slowpath (__slab_alloc_node()). >> > For __prefill_sheaf_pfmemalloc(), the fallback path is available >> > only when gfp_pfmemalloc_allowed() returns true. >> > >> > Reported-by: Chris Bainbridge >> > Closes: https://lore.kernel.org/linux-mm/aZt2-oS9lkmwT7Ch@debian.local >> > Fixes: 1ce20c28eafd ("slab: handle pfmemalloc slabs properly with sheaves") >> > Link: https://lore.kernel.org/linux-mm/aZwSreGj9-HHdD-j@hyeyoo >> > Signed-off-by: Harry Yoo >> >> Thanks, added to slab/for-next-fixes. >> Hopefully Chris can confirm it works (without adding the __NOWARN to btrfs code) > > Yes, it works for my test case. Great, can we add your Tested-by: then? Thanks!