From patchwork Thu Jan 27 15:05:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juan Quintela X-Patchwork-Id: 12727039 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 31CDDC433FE for ; Thu, 27 Jan 2022 16:27:11 +0000 (UTC) Received: from localhost ([::1]:33042 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nD7c5-0006gn-Q2 for qemu-devel@archiver.kernel.org; Thu, 27 Jan 2022 11:27:10 -0500 Received: from eggs.gnu.org ([209.51.188.92]:42548) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nD6b3-0007RC-Qy for qemu-devel@nongnu.org; Thu, 27 Jan 2022 10:22:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:34908) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nD6b1-0004L2-Vc for qemu-devel@nongnu.org; Thu, 27 Jan 2022 10:22:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643296919; h=from:from:reply-to:subject:subject: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=TS6gx8Hyh/qhvZFYSgScu0p5q+84OON1lKmnMJrgHoY=; b=R8uEG+pNYIDaHNOiwPnTpOI9K3Cb5sO0xJAbMRm6UO6pr8KuU0Fu/rbi7Xz8srbiTLCSR4 GtipbNImPdFPT4W3dPH2HygiYPMRyNZ0nxCD8dI+dC7R9L5f+r0n1JB3raeoq766eODTng LEZpp+bKnjCKC3w/8Tg7ossV5osF46M= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-434-9uejBX0cPtSFZMhedaP3Hw-1; Thu, 27 Jan 2022 10:21:56 -0500 X-MC-Unique: 9uejBX0cPtSFZMhedaP3Hw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8508C83DD1F; Thu, 27 Jan 2022 15:21:53 +0000 (UTC) Received: from secure.mitica (unknown [10.39.194.185]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4111972FA2; Thu, 27 Jan 2022 15:21:42 +0000 (UTC) From: Juan Quintela To: qemu-devel@nongnu.org Subject: [PULL 36/38] migration: Add postcopy_has_request() Date: Thu, 27 Jan 2022 16:05:46 +0100 Message-Id: <20220127150548.20595-37-quintela@redhat.com> In-Reply-To: <20220127150548.20595-1-quintela@redhat.com> References: <20220127150548.20595-1-quintela@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=quintela@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.159, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URG_BIZ=0.573 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: , Cc: Fam Zheng , Peter Maydell , "Michael S. Tsirkin" , Jason Wang , Mark Cave-Ayland , Peter Xu , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Gerd Hoffmann , Ani Sinha , "Edgar E. Iglesias" , Eric Blake , Hannes Reinecke , Vikram Garhwal , qemu-block@nongnu.org, Juan Quintela , Daniel Henrique Barboza , Markus Armbruster , Artyom Tarasenko , Pavel Pisa , Alistair Francis , "Dr. David Alan Gilbert" , Greg Kurz , qemu-arm@nongnu.org, =?utf-8?q?C=C3=A9dric_Le_Goater?= , Paolo Bonzini , Stafford Horne , David Gibson , Laurent Vivier , Andrew Baumann , qemu-ppc@nongnu.org, Igor Mammedov , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Peter Xu Add a helper to detect whether postcopy has pending request. Since at it, cleanup the code a bit, e.g. in unqueue_page() we shouldn't need to check it again on queue empty because we're the only one (besides cleanup code, which should never run during this process) that will take a request off the list, so the request list can only grow but not shrink under the hood. Signed-off-by: Peter Xu Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/ram.c | 43 +++++++++++++++++++++++++++---------------- 1 file changed, 27 insertions(+), 16 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 58adcaf430..eb9db4f777 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -355,6 +355,12 @@ static RAMState *ram_state; static NotifierWithReturnList precopy_notifier_list; +/* Whether postcopy has queued requests? */ +static bool postcopy_has_request(RAMState *rs) +{ + return !QSIMPLEQ_EMPTY_ATOMIC(&rs->src_page_requests); +} + void precopy_infrastructure_init(void) { notifier_with_return_list_init(&precopy_notifier_list); @@ -1539,28 +1545,33 @@ static bool find_dirty_block(RAMState *rs, PageSearchStatus *pss, bool *again) */ static RAMBlock *unqueue_page(RAMState *rs, ram_addr_t *offset) { + struct RAMSrcPageRequest *entry; RAMBlock *block = NULL; - if (QSIMPLEQ_EMPTY_ATOMIC(&rs->src_page_requests)) { + if (!postcopy_has_request(rs)) { return NULL; } QEMU_LOCK_GUARD(&rs->src_page_req_mutex); - if (!QSIMPLEQ_EMPTY(&rs->src_page_requests)) { - struct RAMSrcPageRequest *entry = - QSIMPLEQ_FIRST(&rs->src_page_requests); - block = entry->rb; - *offset = entry->offset; - if (entry->len > TARGET_PAGE_SIZE) { - entry->len -= TARGET_PAGE_SIZE; - entry->offset += TARGET_PAGE_SIZE; - } else { - memory_region_unref(block->mr); - QSIMPLEQ_REMOVE_HEAD(&rs->src_page_requests, next_req); - g_free(entry); - migration_consume_urgent_request(); - } + /* + * This should _never_ change even after we take the lock, because no one + * should be taking anything off the request list other than us. + */ + assert(postcopy_has_request(rs)); + + entry = QSIMPLEQ_FIRST(&rs->src_page_requests); + block = entry->rb; + *offset = entry->offset; + + if (entry->len > TARGET_PAGE_SIZE) { + entry->len -= TARGET_PAGE_SIZE; + entry->offset += TARGET_PAGE_SIZE; + } else { + memory_region_unref(block->mr); + QSIMPLEQ_REMOVE_HEAD(&rs->src_page_requests, next_req); + g_free(entry); + migration_consume_urgent_request(); } return block; @@ -2992,7 +3003,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) t0 = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); i = 0; while ((ret = qemu_file_rate_limit(f)) == 0 || - !QSIMPLEQ_EMPTY(&rs->src_page_requests)) { + postcopy_has_request(rs)) { int pages; if (qemu_file_get_error(f)) {