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Biederman" , Ying Huang , , , , , , , , , , , Subject: Re: [PATCH v4 1/4] mm: reduce the rcu lock duration Message-Id: <20220617172316.de2d41877e86be344052b9f5@linux-foundation.org> In-Reply-To: References: <20220530113016.16663-1-linmiaohe@huawei.com> <20220530113016.16663-2-linmiaohe@huawei.com> <87bkvdfzvm.fsf@email.froward.int.ebiederm.org> <87y1yga1r2.fsf@email.froward.int.ebiederm.org> <87ilph90dx.fsf@email.froward.int.ebiederm.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=tMUqy2qF; dmarc=none; spf=pass (imf28.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655511802; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=+QxrNbt82PrmQ/qqJ0Q40cZ33fx8bt4y47T0Xq3jHqY=; b=lykuyBsUSXOuLR4XEAXRDo+sZf+AAxfvjtMSvV1tSZYjxcKmBb/UcWEPxxxtwK8cTqemVR MiYdo04dC8LDSWMAzUpv3KPc6tz+3qmy2Ge8d4msYLBQjmUby1zGtwlOEQt4QVKhq/8mRb K7a9VWvKeqKoTWhTXr1YDnPE074ts0c= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655511802; a=rsa-sha256; cv=none; b=yNpbzgBts0KufiEu1plYIFUCy4sTuzNp+8fVUZpyAt8IkiZUUOR4Gz9H/K9XHDJz/M5MTp /V14u+OCsu84C+NuKT5q4TM6Lv1itCwZnmGzrOwJ71Dxs9+rze1LxaTn49Rfmkd8Sqp2wl JOdvwPwiR7WSV/474cH4jxa2eUEQFEU= X-Stat-Signature: hb6diztaqmmdcwu59nmu3qwzex1wexyk X-Rspamd-Queue-Id: 20BBAC00B6 X-Rspam-User: Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=tMUqy2qF; dmarc=none; spf=pass (imf28.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam10 X-HE-Tag: 1655511801-556336 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, 7 Jun 2022 17:19:53 +0800 Miaohe Lin wrote: > > > > > > If the checks are not made to guarantee they are all checking against > > the same mm, the code needs a comment to say that there is a tiny race. > > The comment should say we don't care about the tiny race because > > the worst that can happen is that a page is migrated to a different > > numa node. And so we don't care. > > > > > > I tend to do this one. To make sure, is the below code change what you suggest? Eric went quiet. As I understand it, any changes arising from this discussion can be done as a followup patch. So I'm planning on moving this 4-patch series into the non-rebasing mm-stable branch late next week.