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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44E23C54EE9 for ; Tue, 20 Sep 2022 09:27:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229832AbiITJ1v (ORCPT ); Tue, 20 Sep 2022 05:27:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229812AbiITJ1p (ORCPT ); Tue, 20 Sep 2022 05:27:45 -0400 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 846C46BCFA for ; Tue, 20 Sep 2022 02:27:44 -0700 (PDT) Received: by mail-pl1-x62d.google.com with SMTP id w13so1792894plp.1 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=kmqpvi2PMHA4hlSy/0qodUn4moKbazkf76KgIuGdVd5vZ/RkeEPrseCFO6iCI/kOuz +c+OKHnGrmQYeBGavqL8PGp3+m0ODW28R7uPx2cupW30zo1w6Qpvisw2yvuUQ9BLgREn YpWsbeQSFsg3AgNyGm1UtN5Ggv9a9g1KYwxUwfadgI9FD7ke6UhuqBFRDBh7/r+8PbF6 ZG1mfMkXrUJAHsZOKkvzhz1qUTKG4LIUTgkQxizZy/LP2xv1lm9NjXpPFndf1Fwl45E7 sH/UMkW0gJ0j1ereDm2s5xF7YGqcoQTv2WHymh5ohO3x8HfrYlxlBJIKQNmyDV8is5ip t/sQ== X-Gm-Message-State: ACrzQf09bD/I+0oEEDmfciqPdi8wacItOu2tiKZDsFA8BTUtefsuX+tI wWBv+JZFop3hajXvRKfwxPY= 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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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