From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.186 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794325188; b=PX4kweYhjgObGwLA8aL4Gl5O66cnWGcy0Qb1KnGfOyWdM/HVk8Sf9LTn59wcDBDmewz0 TdczGJBwGO95Nh06jAaSALEfyJ5jtPucljK0pzYfYBx3QI7o4Z8RE24TYMOEvXJnuYTLl yNdn1Wx6Fc7o39P+rxHvLVt5T2Rz+ljLLNFtwKfwS+oJO4O6f+Bplx/gOG8Xtnw3vyOTY F9M4Hu5GkfkugjUvyI+643ILNI+ikUk/gr5AZMpfHMbtyUHY+4jgQjqJWk7hUjybbOW1U NODN0RUt8EvgjXZqpzb0WgLzhlkcmqhk6BeDO6vCxl6Evx3Dfu/PF1gBHW3WKMc3MdQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794325188; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=/Dc+JwsdmgyYxqvZQmyNcFdizNnWnNQRrjUAX8hzcoU=; b=X/n8oX/NEiW7O8jcfLNbWfEt9NZU0jh8OAtTJ3E13mPo68O0tjGC0EMWNngdqhOwgg8r irGEPRIVeJ73faYv06D3bkSUw/Enw4gWjsV3cazPUZh/LSfYBouEYXT6EbV9ssi5El0gs An/0A3ZLCUUAdCna9/+jTCilEPUFzSA0MLuOkmqXVIlo6pQ+3M9pyHCGvTLigPXjnGqRT 5sD+Uay/JZwhTM6INc3lV5RBRGuraUwHOqCpg6Sv+wgRR6nDblFDW72KTnGiMTFMB4DL1 nSXRw01KmdKL5B1jfa7e6RESxw0rKTWSVVRZztDmH558OMEPejSLUnu2nOGTJkTXA2Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=SsQSQlHy; arc=none smtp.remote-ip=91.218.175.186 Received: from mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C48C3606A321 for ; Tue, 10 Nov 2026 15:39:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org C48C3606A321 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=SsQSQlHy X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=U8k35pxEd0m+x8ZKDuQMkZMM3+/gIzGlGIc3CscMOqM=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794325185; v=1; x=1794929985; b=SsQSQlHyp7V5Z0CCbhyiGrxvJPcWe9+dkoM1G2BZx1xIyZDJVnejZeMb1MALH+7xItNzDytf u6MYKWta7tzzj39/69e7aCn1s1eozEAGLBrWMUMof7KcaaGsU2MKtoOWyxFwM3nG5Xw1DiOl67M zyLFvGH+f39e5KhEBw8n8fu8= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 0bcc4bd1f1aaf32a; Tue, 10 Nov 2026 15:39:45 +0000 X-Mizu-Trace-ID: 0bcc4bd1f1aaf32a X-Migadu-Flow: FLOW_OUT From: Qiliang Yuan To: "Vlastimil Babka (SUSE)" Cc: Qiliang Yuan , Johannes Weiner , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Brendan Jackman , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/2] mm/compaction: stop repeating failed async compaction on every THP fault Date: Tue, 10 Nov 2026 10:39:28 -0500 Message-ID: <20261110153928.4039653-1-qiliang.yuan@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <0a850ec1-d45d-463e-829a-e782290ef864@kernel.org> References: <20261102-bug-mm-thp-async-compact-defer-v2-0-b407e974db54@gmail.com> <20261110135824.3264904-1-qiliang.yuan@linux.dev> <0a850ec1-d45d-463e-829a-e782290ef864@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 11/10/26 15:13, Vlastimil Babka wrote: > The series was nacked twice by senior maintainers. Due to dealing with > urgent issues [1] we might perhaps find time later to see if it reports a > real issue, and in that case fix it ourselves. We have currently no time to > help those who need AI assistance to contribute instead of having own knowledge. > > [1] > https://lore.kernel.org/linux-mm/a2f584f6-e382-4876-aa6d-d5a34de6ee59@kernel.org/ I'm only spending time on this because it gets in the way of AI training and inference, which long-term pin large buffers for RDMA. Mooncake, the KV cache store used with vLLM and SGLang, hit it with 8 ranks x 190GB taking ~38 minutes to register. The stall and the numbers are real, also measured on my own test setup. Async failures have not been deferred since commit 66199712e9ee ("mm: page allocator: do not call direct reclaim for THP allocations while compaction is deferred"), which explained: /* * As async compaction considers a subset of pageblocks, only * defer if the failure was a sync compaction failure. */ That still holds, so the series has no Fixes tag: it isn't a bug in that commit. What the rule doesn't cover is long-term pinned memory, much less common in 2012, where async fails the same way on every fault and is never deferred. The series leaves sync deferral as it is and gives async a state of its own. The analysis and a reproducer are in [2]. If you look at it later, I'm happy to test whatever you come up with. [2] https://lore.kernel.org/r/20261110144256.3841504-1-qiliang.yuan@linux.dev Thanks, Qiliang