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 C9527C433EF for ; Thu, 3 Mar 2022 02:02:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3AECB8D0002; Wed, 2 Mar 2022 21:02:53 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 35CD88D0001; Wed, 2 Mar 2022 21:02:53 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 224328D0002; Wed, 2 Mar 2022 21:02:53 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 111748D0001 for ; Wed, 2 Mar 2022 21:02:53 -0500 (EST) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id D57E6802B9 for ; Thu, 3 Mar 2022 02:02:52 +0000 (UTC) X-FDA: 79201426584.10.5D61ED7 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by imf17.hostedemail.com (Postfix) with ESMTP id 21C7440004 for ; Thu, 3 Mar 2022 02:02:50 +0000 (UTC) Received: from localhost.localdomain (unknown [10.20.42.95]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dxn8_FISBiuqsBAA--.8781S3; Thu, 03 Mar 2022 10:02:46 +0800 (CST) Subject: Re: [PATCH 1/1] mm/page_alloc: add scheduling point to free_unref_page_list To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220302013825.2290315-1-wangjianxing@loongson.cn> <20220302153433.719caef31bd9e99319c5e6a2@linux-foundation.org> From: wangjianxing Message-ID: Date: Thu, 3 Mar 2022 10:02:45 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20220302153433.719caef31bd9e99319c5e6a2@linux-foundation.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-CM-TRANSID:AQAAf9Dxn8_FISBiuqsBAA--.8781S3 X-Coremail-Antispam: 1UD129KBjvJXoW7Kr15WF4kCw1rJFy5Kr45Jrb_yoW8GrWkpr n5Jw1Dtr1DJws5Jw4xtrn29rWrCanxKrn7Xry8tFW3JasxXrnIqFykKFZI9Fy7G3y8C3yS q3y8Kw4rZa1qqFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUv2b7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4 vEx4A2jsIEc7CjxVAFwI0_Cr1j6rxdM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVAC Y4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJV W8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7I2V7IY0VAS07AlzVAYIcxG 8wCY02Avz4vE-syl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxV Aqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1Y 6r17MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6x kF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s0DMIIF0xvEx4A2jsIE 14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Jr0_GrUvcSsGvfC2KfnxnUUI43ZEXa 7IU5PpnJUUUUU== X-CM-SenderInfo: pzdqwyxldq5xtqj6z05rqj20fqof0/ X-Rspamd-Queue-Id: 21C7440004 X-Stat-Signature: 9ghjpmq49x7mhtycuugn5s879rxtjw6z Authentication-Results: imf17.hostedemail.com; dkim=none; spf=pass (imf17.hostedemail.com: domain of wangjianxing@loongson.cn designates 114.242.206.163 as permitted sender) smtp.mailfrom=wangjianxing@loongson.cn; dmarc=none X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1646272970-691903 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 03/03/2022 07:34 AM, Andrew Morton wrote: > On Tue, 1 Mar 2022 20:38:25 -0500 wangjianxing wrote: > >> free a large list of pages maybe cause rcu_sched starved on >> non-preemptible kernels >> >> rcu: rcu_sched kthread starved for 5359 jiffies! g454793 f0x0 >> RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=19 >> [...] >> Call Trace: >> free_unref_page_list+0x19c/0x270 >> release_pages+0x3cc/0x498 >> tlb_flush_mmu_free+0x44/0x70 >> zap_pte_range+0x450/0x738 >> unmap_page_range+0x108/0x240 >> unmap_vmas+0x74/0xf0 >> unmap_region+0xb0/0x120 >> do_munmap+0x264/0x438 >> vm_munmap+0x58/0xa0 >> sys_munmap+0x10/0x20 >> syscall_common+0x24/0x38 > Thanks. > > How did this large list of pages come about? > > Will people be seeing this message in upstream kernels, or is it > specific to some caller code which you have added? > > Please always include details such as this so that others can determine > whether the fix should be backported into -stable kernels. Thanks. I try to increase the overcommit ratio of cpu to 1:2~1:3 in KVM hypervisor, per-vm has the same number of vcpu with host cpu, then setup 2 or 3 vm. Run ltpstress test in per vm, both host and guest is non-preemptiable kernel, vm dmesg will throw some rcu_sched warning. ltp version is 20180926, but until now I didn't analysis ltpstress code deeply.