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 B0FCAC433EF for ; Thu, 10 Mar 2022 03:29:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 012DC8D0002; Wed, 9 Mar 2022 22:29:53 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F043E8D0001; Wed, 9 Mar 2022 22:29:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DCBC38D0002; Wed, 9 Mar 2022 22:29:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id C92ED8D0001 for ; Wed, 9 Mar 2022 22:29:52 -0500 (EST) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 8CD6A24045 for ; Thu, 10 Mar 2022 03:29:52 +0000 (UTC) X-FDA: 79227047424.13.8C9B633 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf27.hostedemail.com (Postfix) with ESMTP id C00E140012 for ; Thu, 10 Mar 2022 03:29:51 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E9E4AB81EAA; Thu, 10 Mar 2022 03:29:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85CF6C340E8; Thu, 10 Mar 2022 03:29:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1646882988; bh=Y3t4lV1jIoKGK4m2yMyigJhYuqSRKau7FAkkcqBIRb0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TGA/6LQtGGREJgckJiJnRD6BRW/t2sHNz8Y9nex10J6D2Jza2f3UDYQNwFE2OQnQt QxC9JUuYQ7NTU7yHY3QfCnp0l/AAzP02c8DDweQlbhE98WqTAEn3gDRHYaZcpMY4hB YPtYY8xQHe5TB2TluBh/+11jrp8Iel64ITQ1S8Cs= Date: Wed, 9 Mar 2022 19:29:47 -0800 From: Andrew Morton To: wangjianxing Cc: Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org, vbabka@suse.cz Subject: Re: [PATCH 1/1] mm/page_alloc: add scheduling point to free_unref_page_list Message-Id: <20220309192947.0b4c8c875c492de09c1ab632@linux-foundation.org> In-Reply-To: <3713cb82-9596-9916-9830-c2827d6a6fe4@loongson.cn> References: <20220302013825.2290315-1-wangjianxing@loongson.cn> <20220309170517.05facf4a2d183cc9aac9196d@linux-foundation.org> <3713cb82-9596-9916-9830-c2827d6a6fe4@loongson.cn> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C00E140012 X-Stat-Signature: zm5b65pi4eudiosumoj619mwyqpsk4mq Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b="TGA/6LQt"; dmarc=none; spf=pass (imf27.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1646882991-897100 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 Thu, 10 Mar 2022 10:48:41 +0800 wangjianxing = wrote: > spin_lock will preempt_disable(), interrupt context will=20 > __irq_enter/local_bh_disable and also add preempt count with offset. >=20 > cond_resched check whether if preempt_count =3D=3D 0 in first and won't=20 > schedule in previous context. >=20 > Is this right? >=20 >=20 > With another way, could we add some condition to avoid call cond_resched= =20 > in interrupt context or spin_lock()? >=20 > + if (preemptible()) > +=A0=A0 =A0=A0=A0 cond_resched(); >=20 None of this works with CONFIG_PREEMPTION=3Dn.