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[195.38.113.151]) by smtp.gmail.com with ESMTPSA id jv16-20020a170907769000b0073d6ab5bcaasm1596941ejc.212.2022.08.21.04.28.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Aug 2022 04:29:00 -0700 (PDT) Date: Sun, 21 Aug 2022 13:28:58 +0200 From: Ingo Molnar To: Mel Gorman Cc: Linus Torvalds , David Hildenbrand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, Andrew Morton , Greg Kroah-Hartman , Axel Rasmussen , Peter Xu , Hugh Dickins , Andrea Arcangeli , Matthew Wilcox , Vlastimil Babka , John Hubbard , Jason Gunthorpe , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt Subject: Re: [PATCH v2] sched/all: Change all BUG_ON() instances in the scheduler to WARN_ON_ONCE() Message-ID: References: <20220808073232.8808-1-david@redhat.com> <1a48d71d-41ee-bf39-80d2-0102f4fe9ccb@redhat.com> <20220815144143.zjsiamw5y22bvgki@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220815144143.zjsiamw5y22bvgki@suse.de> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661081342; a=rsa-sha256; cv=none; b=UQvf+cHvCM7SrlU3PVDo1NLaDpzHqsQRGze4snlTAhDoodwspnqyJGVQ/6SiR4mJLVoaOg UPik+6leH6v19ZYH6p37C/rLj7S13ydgNcYD40B3ncsR3AzFlVAH5TKqCJ+GxFOPEsDfVJ ylJp5Vljd4/lJU/YXf1wjP3BUCRFMVU= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=Pl0IJgXi; spf=pass (imf05.hostedemail.com: domain of mingo.kernel.org@gmail.com designates 209.85.218.51 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661081342; h=from:from:sender: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=fMM08NkXjQf8LQsd9if/tOzac0dPGc2gucFpi22QVMQ=; b=jFAOxhPen+1y9aP/NnhXU8OpkOIc+oeae41asdK2XRKZod/noaMY+/HSC/0LTUO+jSC26c y/ccFdy7ThLZKDKamw+lV3fRv9pYAtgZJ6kO46A9bLzynf0UjrQAK5zwhLBqvX2emPXprt +Tmstg33haFOOMZQXGPEzYZ4yhPMHLU= X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 7144010002A X-Rspam-User: Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=Pl0IJgXi; spf=pass (imf05.hostedemail.com: domain of mingo.kernel.org@gmail.com designates 209.85.218.51 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none) X-Stat-Signature: 8g3u3rtfgi4yowak7npjhauyqdaubogr X-HE-Tag: 1661081342-834495 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: * Mel Gorman wrote: > For the rest, I didn't see obvious recovery paths that would allow the > system to run predictably. Any of them firing will have unpredictable > consequences (e.g. move_queued_task firing would be fun if it was a > per-cpu kthread). Depending on which warning triggers, the remaining life > of the system may be very short but maybe long enough to be logged even > if system locks up shortly afterwards. Correct. I'd prefer to keep all these warnings 'simple' - i.e. no attempted recovery & control flow, unless we ever expect these to trigger. I.e. instead of adding a 'goto' I'd prefer if we removed most of the ones you highlighted. But wanted to keep this first patch simple. Thanks, Ingo