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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D2A0BCDB482 for ; Thu, 19 Oct 2023 14:58:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qtUTc-0002gl-Oo; Thu, 19 Oct 2023 10:58:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qtUTa-0002Xi-TM for qemu-devel@nongnu.org; Thu, 19 Oct 2023 10:58:18 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qtUTZ-00085F-Dl for qemu-devel@nongnu.org; Thu, 19 Oct 2023 10:58:18 -0400 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-out1.suse.de (Postfix) with ESMTPS id 404A221A80; Thu, 19 Oct 2023 14:58:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1697727496; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oPPSTrteIjwLwcDXSrWIPEVGaBqZ94eF+TmZVLoXbwo=; b=C56bBsMKUcKSkLdvPgetD4FBI1xkU0huqTID6nkWa5wb2SIV6J/mxYhddt/kPWERienZji RL4wHr1TpT0veo0Le94VKJ2ey3s9Q8JVlcDWGkEzWI1YtSVs9ztAT5gw/Aleg/CybRmOHl 87PSOQJJCbNbpLEWGkdOkc9xW+1ZjCc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1697727496; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oPPSTrteIjwLwcDXSrWIPEVGaBqZ94eF+TmZVLoXbwo=; b=Y+YtyZ99gT3Odcjq7pCO/gFRy2tw4wmBoL5ag7RwxmxenCxN9ld6Rw7RLtnG0eTusD/JOo SbA8tNNSp9hv56DA== 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 C89131357F; Thu, 19 Oct 2023 14:58:15 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id eE2UJAdEMWUoEwAAMHmgww (envelope-from ); Thu, 19 Oct 2023 14:58:15 +0000 From: Fabiano Rosas To: quintela@redhat.com Cc: qemu-devel@nongnu.org, Peter Xu , Leonardo Bras , Elena Ufimtseva Subject: Re: [RFC PATCH v2 2/6] migration/multifd: Stop checking p->quit in multifd_send_thread In-Reply-To: <87o7gv6kt6.fsf@secure.mitica> References: <20231012140651.13122-1-farosas@suse.de> <20231012140651.13122-3-farosas@suse.de> <87o7gv6kt6.fsf@secure.mitica> Date: Thu, 19 Oct 2023 11:58:13 -0300 Message-ID: <87o7guy7zu.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-6.03 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; BAYES_HAM(-1.93)[94.64%]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-3.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_FIVE(0.00)[5]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-1.00)[-1.000]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[] Received-SPF: pass client-ip=195.135.220.28; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Juan Quintela writes: > Fabiano Rosas wrote: >> We don't need to check p->quit in the multifd_send_thread() because it >> is shadowed by the 'exiting' flag. Ever since that flag was added >> p->quit became obsolete as a way to stop the thread. >> >> Since p->quit is set at multifd_send_terminate_threads() under the >> p->mutex lock, the thread will only see it once it loops, so 'exiting' >> will always be seen first. >> >> Note that setting p->quit at multifd_send_terminate_threads() still >> makes sense because we need a way to inform multifd_send_pages() that >> the channel has stopped. >> >> Signed-off-by: Fabiano Rosas > > Reviewed-by: Juan Quintela > > But then should we remove the quit altogether? > It still serves a purpose to allow multifd_send_pages() to see that the channel has exited. While that function does also check multifd_send_state->exiting, it could already be waiting at the mutex when the channel aborts. So we need to either check 'exiting' again or keep p->quit.