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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 176F6C433EF for ; Tue, 8 Mar 2022 16:05:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348020AbiCHQGB (ORCPT ); Tue, 8 Mar 2022 11:06:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243062AbiCHQF7 (ORCPT ); Tue, 8 Mar 2022 11:05:59 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 370AE4FC5F for ; Tue, 8 Mar 2022 08:05:01 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id A441B1F380; Tue, 8 Mar 2022 16:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1646755500; h=from:from:reply-to: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; bh=cFXVe88c1y/NL2/upYftgWSKkejjurmLEVpRnE2EA/Y=; b=iI3lDH21RP0cKXGVnGPKUzmdG7NTt0kRACKOMEZL2kTUMlChz3rZ/J4bZreY7DtNPP0PgC KhnRnS7eRAH19aCMd0HINZm5+w0AqDiv2kkHF8yUmzANU7pza0gz092RVDyg00t7ZL/mPK Hu41KZBCV8SHYzeTjb0UF3Yijzfa0pc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1646755500; h=from:from:reply-to: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; bh=cFXVe88c1y/NL2/upYftgWSKkejjurmLEVpRnE2EA/Y=; b=XwizUuTzRGXwU7cSsun7gDcguu+KX475OmeMHBlEtERedLd1nYjgKma3V28BUw33vPN6K5 ZwRh1s6msbgEUxBA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 85F9D13CCE; Tue, 8 Mar 2022 16:05:00 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id fcA4IKx+J2IKaAAAMHmgww (envelope-from ); Tue, 08 Mar 2022 16:05:00 +0000 Message-ID: Date: Tue, 8 Mar 2022 17:04:59 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH 1/1] mm/page_alloc: add scheduling point to free_unref_page_list Content-Language: en-US To: Andrew Morton , wangjianxing Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , Mel Gorman References: <20220302013825.2290315-1-wangjianxing@loongson.cn> <20220302153433.719caef31bd9e99319c5e6a2@linux-foundation.org> From: Vlastimil Babka In-Reply-To: <20220302153433.719caef31bd9e99319c5e6a2@linux-foundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/3/22 00:34, 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? Looks like it came from TLB batching. But I got lost in the maze of it trying to figure out how large the batch can grow. > 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. > >