From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42EC6C3DA4A for ; Thu, 22 Aug 2024 09:41:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B03C46B027D; Thu, 22 Aug 2024 05:41:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AB1478001E; Thu, 22 Aug 2024 05:41:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 952BF6B027F; Thu, 22 Aug 2024 05:41:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 7353A6B027D for ; Thu, 22 Aug 2024 05:41:28 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E4AC7161463 for ; Thu, 22 Aug 2024 09:41:27 +0000 (UTC) X-FDA: 82479388614.06.127A62A Received: from mail-ed1-f52.google.com (mail-ed1-f52.google.com [209.85.208.52]) by imf05.hostedemail.com (Postfix) with ESMTP id EE44710001F for ; Thu, 22 Aug 2024 09:41:25 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=UzXZUxlG; spf=pass (imf05.hostedemail.com: domain of mhocko@suse.com designates 209.85.208.52 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724319645; a=rsa-sha256; cv=none; b=KfXqIDErcXmEE/LzpsrBc4uOSmYNsXxGGfjuyP5fQv4sHuWWZtAA9suXoNfi2kBxfI8b0d YutgNz5m8jgWVWuykfZJdqTXwEJWtL/WD7zdTBI+H3rMbZx2+E78/6PaiDMGW4OaOsFYpF mQatispK3Kf9J20pJK2UCEjpI2GtGIw= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=UzXZUxlG; spf=pass (imf05.hostedemail.com: domain of mhocko@suse.com designates 209.85.208.52 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724319645; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=w8SH5AeNo6r9c+QnGllsu0v0n00fvJPRVyLfkrH1Iuk=; b=BPUGloVpm2cEVVQbM5JR4PaziGtr5DaxHhiDefSwkmospiyAb5MJy0o0rMR3VwLNcaX5Ar mefeJ05UqwIY0zK+sbCBJ/82/LD9PNM0UwBpE7md6blB7lk4KfAraCNdArjU377rgHM+da vQzgq/vsniJUr8i0NTNt2vT7dThKBv0= Received: by mail-ed1-f52.google.com with SMTP id 4fb4d7f45d1cf-5bf0261f162so935013a12.0 for ; Thu, 22 Aug 2024 02:41:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1724319684; x=1724924484; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=w8SH5AeNo6r9c+QnGllsu0v0n00fvJPRVyLfkrH1Iuk=; b=UzXZUxlGG2C4lIpEXkDjrqTnkzSYihFXGiLvVQzeSS+57tKdS3Gb4sdjfH5ZdGHZs3 Vp8j22bMuuDAKQfgQk2kI7AsAO4b4warLDFNMQnKWGaiW9CuCN+ftGcm6KPGWaHxFe8V ofNpFM6pQDrQfXcnOrl3AxDha48vb5KrK+KtDYnMnh8wQr7Wu8fu/hege9SI6y+udDci yrgGBZ3Mg+yw0IWmCu8tJ8GBiv0ML/nfe7f/f1SGrzdP3GrTv9Uer7Vcs4s/A1PeClDY 0DWUQhJist6JWQKv+0RgN4CQW/5CB7lwyFz7+jMnmmVDyuO3uPJKlpPXoZ8ZQMxoxz6s XM2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724319684; x=1724924484; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=w8SH5AeNo6r9c+QnGllsu0v0n00fvJPRVyLfkrH1Iuk=; b=PQolIU990H47CjqL7MJWNbF3pOQgYtMm3il1vSN2Nc5M1JNuBp5uOjdoIVt1nIbV6M hxeVJGNX8xLOtbcYZhjolfliS+WxbSi1pFjHkIZksaCKtSDG6sU9pZOmm8RnJMmyBLeA QJvW5suec3x+Bx7z2liFyKASDo8C5Aw18maOwSorx8jbqMxFC+3xIswQBMrsWmCTCREq MNDrnB0V8lbUvauQDU3RmGPGETv3a1LGYltaKjP8ggONFBd6qQUOLkrGmFHuxntgqDd1 xTMXY14KJUQ9r0gGdFRRjcHdlxkfPjmJgQavrCPxValMorae8GfrN3w2/Er1aMsRiQxm ss9A== X-Forwarded-Encrypted: i=1; AJvYcCV4GZr++277+Hr8OisSyDXNFRiQPOXDKn4ZLqGeT6ggxa3mVlmS6xsJqNKgk/7CtAyl8eAOoDKqUQ==@kvack.org X-Gm-Message-State: AOJu0Yy9XxXDzVeXR7y4/+c0V3TS+B73TqC1X+BnSSY9j61yBSqDwzkZ 9yW4WemPZ7pUJIOByVtGoTJ8I0HIqr6BUhJ67LihCS+n1/JXf5i/SWBR1YSVtc0DYhAurbvwiE4 P X-Google-Smtp-Source: AGHT+IELqOefPJ8psfpJSjnaSaKWJC6Dc+LHxP3cO0ykfHQjKl2FHz2qDjDbsW8KcyOaDVWiYjTLTw== X-Received: by 2002:a05:6402:4407:b0:5a3:a9f8:cf20 with SMTP id 4fb4d7f45d1cf-5c0792b0d8cmr770050a12.34.1724319684224; Thu, 22 Aug 2024 02:41:24 -0700 (PDT) Received: from localhost (109-81-92-13.rct.o2.cz. [109.81.92.13]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5c04a3cbdeasm693091a12.33.2024.08.22.02.41.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Aug 2024 02:41:24 -0700 (PDT) Date: Thu, 22 Aug 2024 11:41:23 +0200 From: Michal Hocko To: David Hildenbrand Cc: Barry Song <21cnbao@gmail.com>, Linus Torvalds , Yafang Shao , akpm@linux-foundation.org, linux-mm@kvack.org, 42.hyeyoo@gmail.com, cl@linux.com, hailong.liu@oppo.com, hch@infradead.org, iamjoonsoo.kim@lge.com, penberg@kernel.org, rientjes@google.com, roman.gushchin@linux.dev, urezki@gmail.com, v-songbaohua@oppo.com, vbabka@suse.cz, virtualization@lists.linux.dev Subject: Re: [PATCH v3 0/4] mm: clarify nofail memory allocation Message-ID: References: <59e90825-4efa-4384-8286-06c0235304dc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <59e90825-4efa-4384-8286-06c0235304dc@redhat.com> X-Stat-Signature: 7z1nz4jugsjrqj1g174utw31ey3gwep1 X-Rspamd-Queue-Id: EE44710001F X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1724319685-749768 X-HE-Meta: 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 FpWO8U6S 9IPN6ZK+bTKljC7m5tvFB8LRNDIRU+wBRZhgMvKeu/+o5pOT1Wq8XO8TQNcFevOEY2F1Fk/ffx678ap1a15MU4Szf+Q/Wn1sLvVgiXwXRuRuubHWiTH9EomtBsbH/YKC+efyM0HpQyMmCG8xcu3SRQCNWZpCIF/mg3vEWpu/o4P6K/PRLM/wYdvGKEebonTs9z5/XJ6QyLenDTiOv+WQxdGo/jA9OYejzfkJyKJiKCycpzuvOIXBawL6kHSGA4uN5Tz+q8iy1//3zohb9l0WoaJyTSkKNjmUevq1JSZZBOwev+0ba+mxSoMl2Fjx4rnDUSOjnBTUsiy/0xfZTUkP5/xwNaaC2RdcgDJ92hCq0dKl1kRE= 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 Thu 22-08-24 11:27:25, David Hildenbrand wrote: [...] > Likely, checkpatch should be updated to warn on any new NOFAIL usage. What do you expect people to do? I do not see a pattern of nilly-willy use of the flag (we have less than 200 in the kernel outside of mm, compare that to 40k GFP_KERNEL allocations). If you warn and the only answer is shrug and go on then this serves no purpose. I have learned couple of things. People do not really give a deep thought on the naming (e.g. GFP_TEMPORARY story). Or a documentation (e.g. GFP_NOWAIT | GFP_NOFAIL user). They sometimes pay attention to warnings but WARN_ON_ONCE tells you about a single abuser... I believe that enforcing a constrains for GFP_NOFAIL by killing the allocation user context would have a more visible effect than WARN_ON and it would stop potential silent failure mode at the same time. -- Michal Hocko SUSE Labs