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 DC149ECAAD8 for ; Tue, 20 Sep 2022 09:27:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 24FF4940008; Tue, 20 Sep 2022 05:27:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 200C3940007; Tue, 20 Sep 2022 05:27:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0C84D940008; Tue, 20 Sep 2022 05:27:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id F1B49940007 for ; Tue, 20 Sep 2022 05:27:45 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9E0B040327 for ; Tue, 20 Sep 2022 09:27:45 +0000 (UTC) X-FDA: 79931936490.24.D8B5472 Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) by imf13.hostedemail.com (Postfix) with ESMTP id 145D820010 for ; Tue, 20 Sep 2022 09:27:44 +0000 (UTC) Received: by mail-pj1-f53.google.com with SMTP id bu5-20020a17090aee4500b00202e9ca2182so1105482pjb.0 for ; Tue, 20 Sep 2022 02:27:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date; bh=138IjAg8FELHzInvjsbFPKlTcrvjuLJXi6QY0IdyC9s=; b=mYpgHOS2UXARVYgXPgPsv7uXK5FNk1Hn7a6MtMG/+YHW1Nis2O/H6DWw700hAesdkv HyhUROVWGo20nnP5r4WF53L8eHo/F48m3awsXOHVodA8nEvKnnaqtXPkbPqFlW2jdiMJ SPwcEKD3E4HicTK3cOroLwlVnhttf+OlHRMWvGZd+s7c1+0eu9WQRKGeHItaB/k9UAOR YNrcfTlnNahKpeTdYAs+MvLvZZ2lDHz7fLctX3v4iu/qH1gHsUcAVYPVFuAN4IVxxNi/ OMzFkLdJtT5g0ZYoueJMxWu3Z2YUhoqbgdBN93lN4djYLFalTnxLYAHKqdnsVVwalHJw OqZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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; bh=138IjAg8FELHzInvjsbFPKlTcrvjuLJXi6QY0IdyC9s=; b=3UuPWCbbi+ft8sQ+jhJzmLQFnpcY0sA2hA1R/hhj4+/2jExjpLI28EUouv6XhcZUGW 7TBFEonIQAf79dtT27r+9He+wnzZ36OJ9laS0L2OM/Cu00NPPKqugK42Y/K22OjiLQEA uwnq/9IvyXoqKg74TB2tPpB0kSHm2AS8cQAmginLRqRrH2iN9hbS4xTtA6+IiuSY+9TA VPiJ4IumSFa0ZE/fP9Vm4Sk4siPxywb8Ia1engkClYC976oyF2gdRMJ7DTkKUFluMLEp JIHjdrIFAPtig3sXWGPFhIdvWzcV/v6tiw/9zX1bSmfORb/Y9ci2jazbIy2qoM/V/eRA Ic/A== X-Gm-Message-State: ACrzQf3gHSuCLgvh0kBwDQs1nabkOJYd6B+2OIXr4k1WKyaLZRfaBg3N V3NYeCyIm4kvB5aM4IIYxPs= X-Google-Smtp-Source: AMsMyM75Lm84hqwlOxxJUd2zALFuMOj/L6Qm8eENlebmJsJ3K/QpAindEwA4TuZjVyex/yhbSTfeSg== X-Received: by 2002:a17:90b:3803:b0:203:a31c:e2e9 with SMTP id mq3-20020a17090b380300b00203a31ce2e9mr2797280pjb.13.1663666063919; Tue, 20 Sep 2022 02:27:43 -0700 (PDT) Received: from hyeyoo ([114.29.91.56]) by smtp.gmail.com with ESMTPSA id l7-20020a170903120700b001766a3b2a26sm943369plh.105.2022.09.20.02.27.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Sep 2022 02:27:43 -0700 (PDT) Date: Tue, 20 Sep 2022 18:27:37 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Sebastian Andrzej Siewior Cc: Maurizio Lombardi , vbabka@suse.cz, linux-mm@kvack.org, rientjes@google.com, penberg@kernel.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3] mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context. Message-ID: References: <20220919163929.351068-1-mlombard@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663666065; a=rsa-sha256; cv=none; b=wakS5PlIRD6eN3MLl5YMOQNtun1T18p7km6ug3ys73TzzjdS9BPsddA8jm1GFvkbWJC9H6 feFLK31+YcLLMVsnvoLd2YJZo4zZX+VjQoG6v56gXf1YrdkR+RNkZX5YsclmqwkUVB3yhg rRfDs+p/4ifZ0Vxo7N9LHui0DTFYafQ= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=mYpgHOS2; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf13.hostedemail.com: domain of 42.hyeyoo@gmail.com designates 209.85.216.53 as permitted sender) smtp.mailfrom=42.hyeyoo@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663666065; 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=138IjAg8FELHzInvjsbFPKlTcrvjuLJXi6QY0IdyC9s=; b=H6AsC8J4HidYjnq9Q/K8BIHb+pXYdargW4pQ6TUcKOeAEfmEEbhxImfz/G0X5i75SEAEBw +QBvkzXRukz4RURdrpqyh9adtFLvDwqi8uL9nb6ZSuGAF2QkaTIeNn30KpvlTZM03v1ZOD ml+PsKB8lrxobES4T0ahIyG5raAFSPg= X-Rspamd-Queue-Id: 145D820010 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=mYpgHOS2; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf13.hostedemail.com: domain of 42.hyeyoo@gmail.com designates 209.85.216.53 as permitted sender) smtp.mailfrom=42.hyeyoo@gmail.com X-Rspamd-Server: rspam08 X-Rspam-User: X-Stat-Signature: bw4h9m5howmc19tsmc96rmuw1ody6zup X-HE-Tag: 1663666064-823204 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: On Tue, Sep 20, 2022 at 09:56:59AM +0200, Sebastian Andrzej Siewior wrote: > On 2022-09-20 16:46:41 [+0900], Hyeonggon Yoo wrote: > > > @@ -2730,7 +2735,7 @@ static void flush_all_cpus_locked(struct kmem_cache *s) > > > INIT_WORK(&sfw->work, flush_cpu_slab); > > > sfw->skip = false; > > > sfw->s = s; > > > - schedule_work_on(cpu, &sfw->work); > > > + queue_work_on(cpu, flushwq, &sfw->work); > > > > Hi. what happens here if flushwq failed? > > > > I think avoiding BUG_ON() makes sense, > > but shouldn't we have fallback method? > > You get an output to act on and fix. The point is that it shouldn't have > happen in the first place. With the bug_on() that early, chances are > that you never see anything but a blank screen. So with the warn_on you > get probably to see the warn_on before you get here. > > Sebastian Thank you for kind explanation. Makes sense! -- Thanks, Hyeonggon