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 B1BF8ECAAD8 for ; Tue, 20 Sep 2022 07:57:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2A31C940008; Tue, 20 Sep 2022 03:57:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 25267940007; Tue, 20 Sep 2022 03:57:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 14182940008; Tue, 20 Sep 2022 03:57:04 -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 05DE8940007 for ; Tue, 20 Sep 2022 03:57:04 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 9DCD4A0C19 for ; Tue, 20 Sep 2022 07:57:03 +0000 (UTC) X-FDA: 79931707926.05.1A1A1B4 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf30.hostedemail.com (Postfix) with ESMTP id 297F780003 for ; Tue, 20 Sep 2022 07:57:02 +0000 (UTC) Date: Tue, 20 Sep 2022 09:56:59 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1663660621; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=sCP9yCQxHK6W8zHLhqzhqlMNVNEueRQZsr8D5yISAcA=; b=F3DZmMwmkTWUYbHkI5PkXxTCHsXuUfdPA4SDS+pXBz4c+aOIVMsQqJHyJ91jqBeunczZUK xy1SuRjyW+/0aFJIYmWjkzVckARm/9nh0frSlKF7BG7nZIBlpmCYChFFNXbqKNNj6GnpRk uIR61kI/wzQrWDIkqycFLVo3/UDc9cVW9Foc9cbpoR8BkJx/eJjTRui66UAxjY8t2n0T58 +SJj1whEfmToVyHTPRRBdby/JhmWeNEMdX9fmaKfELxh6UzlUWlTh22WrehiKSAeGjcnQ8 QTiQmC1CVS3l8wk6HHbdb0xKoI6GEXXR2hJWc1mMQb/czM6sABurXX+FCWaMfw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1663660621; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=sCP9yCQxHK6W8zHLhqzhqlMNVNEueRQZsr8D5yISAcA=; b=t4fqyrc35iuryhQT7o7XzHa4e+Oqg5YW5RryTnAtZF8vYmXrMNFsvJyj0hLJVqn5w859Lh oKdSpSKrroythzCg== From: Sebastian Andrzej Siewior To: Hyeonggon Yoo <42.hyeyoo@gmail.com> 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=utf-8 Content-Disposition: inline In-Reply-To: ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663660623; 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=sCP9yCQxHK6W8zHLhqzhqlMNVNEueRQZsr8D5yISAcA=; b=i9O0/PJmUzaWALo/aTPKCfzlbkXxH89eAtgkxPc7/tDq3bSLAzG7/PYy28jQdnQhluHxCb m6pteQTmubGjOvs/c2yOaCF4W1BJx+sqitDkqmj556x0AjHYNGa2S7lKSje8FETv6rJZpo jFszovv4Kz4k2XAG6Y9zvO0eOPOWLJE= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b=F3DZmMwm; dkim=pass header.d=linutronix.de header.s=2020e header.b=t4fqyrc3; spf=pass (imf30.hostedemail.com: domain of bigeasy@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=bigeasy@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663660623; a=rsa-sha256; cv=none; b=tFVaPugM8/Y51UBMe9kLyh1fPPZhL9PSQiYZZ7XRVhmC1jvUSCZPFAAFZS3vGdIDQkOMe/ xMsyB5kJD7OqawHUyiVLCbHAB671O+tiI+XU/k/6GEDVDUMO3Ucpi/4AOXOzlCaJWI6K3n gehqLiUzIt6nCsPkjJgvN0kQJtsNxRY= X-Stat-Signature: c84h3fo8si78eqt4yuqcot8oiugxu9jf X-Rspam-User: X-Rspamd-Queue-Id: 297F780003 X-Rspamd-Server: rspam02 Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b=F3DZmMwm; dkim=pass header.d=linutronix.de header.s=2020e header.b=t4fqyrc3; spf=pass (imf30.hostedemail.com: domain of bigeasy@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=bigeasy@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de X-HE-Tag: 1663660622-875012 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 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