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 DD276C433F5 for ; Tue, 8 Mar 2022 16:19:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6AD048D0002; Tue, 8 Mar 2022 11:19:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 635998D0001; Tue, 8 Mar 2022 11:19:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4FE008D0002; Tue, 8 Mar 2022 11:19:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0046.hostedemail.com [216.40.44.46]) by kanga.kvack.org (Postfix) with ESMTP id 40F358D0001 for ; Tue, 8 Mar 2022 11:19:40 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 06E648248076 for ; Tue, 8 Mar 2022 16:19:40 +0000 (UTC) X-FDA: 79221729720.29.4782AD5 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 229E1140011 for ; Tue, 8 Mar 2022 16:19:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=sASMybBrruIZ7UAl7EnuiTVPbgVunRsSkPublV647Io=; b=QKt6YpZPpbh1aIjSJYBw5RftaP rrdz251VjwiOEpgOF15uOaEvvjTOXHmx0IV7zxw5urSVbFPSZxcbyXjIfCTBTvtBYdkKior1aFzzM Uljoalk56W3HBwZdfY5HpnrLQ3MAyX1c1lHw8y6woD2nK2K+jTdBLXnZNj/k1LX5CzvEG/2weMCSo bjwmWJ1AxTBLBjNacJ32d7ZU/aiYEdyQSBhfQ6K5Czuzxbq/5rNxsgraT8OTYsQ1/YuV0CiJCYKLI dXo8wMrbASfixX07Zj+Yn58BSA27t90SXbnt1tArQODXbbHDQJIKQlwd9c7LG3OF5dsRpHhj+KmmH CwcWmVvA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRcYf-00GKUW-1o; Tue, 08 Mar 2022 16:19:33 +0000 Date: Tue, 8 Mar 2022 16:19:33 +0000 From: Matthew Wilcox To: wangjianxing Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] mm/page_alloc: add scheduling point to free_unref_page_list Message-ID: References: <20220302013825.2290315-1-wangjianxing@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220302013825.2290315-1-wangjianxing@loongson.cn> X-Rspamd-Server: rspam10 X-Rspam-User: X-Stat-Signature: r74bgmukgshpginhd638t7xi4bffxtoe Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=QKt6YpZP; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Queue-Id: 229E1140011 X-HE-Tag: 1646756378-56052 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, Mar 01, 2022 at 08:38:25PM -0500, wangjianxing wrote: > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3589febc6..1b96421c8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3479,6 +3479,9 @@ void free_unref_page_list(struct list_head *list) > */ > if (++batch_count == SWAP_CLUSTER_MAX) { > local_unlock_irqrestore(&pagesets.lock, flags); > + > + cond_resched(); This isn't safe. This path can be called from interrupt context (otherwise we'd be using local_unlock_irq() instead of irqrestore()).