From patchwork Fri Jan 26 04:17:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 1891116 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=H/L8B6CD; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TLkvZ6Lz8z23f9 for ; Fri, 26 Jan 2024 15:18:17 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rTDf3-0001k4-MN; Thu, 25 Jan 2024 23:17:49 -0500 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 1rTDf2-0001ja-9g for qemu-devel@nongnu.org; Thu, 25 Jan 2024 23:17:48 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rTDf0-0004pb-Kj for qemu-devel@nongnu.org; Thu, 25 Jan 2024 23:17:47 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706242665; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yOIHVYyv54egdlVoMdUVLVFk4lzZ/xlT1WvDt+htyXc=; b=H/L8B6CDo6mCUnCsoGj2c8DU2vEyq9W9SvrxIPD5Fh1QQbB9yCheuAmhPnxOrVe4MOK8ly szYgFXwBOdXx47Ef9r3X0XPbDAGH12FGG7LTBjAaaGbeOcJux+wNDo6SXcMP0nbrK67zGu jOikKgmMaxKi6JtjTnN3A678RDDwPy4= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-18-1j3nIyv_Pci_P4-hYm_S3A-1; Thu, 25 Jan 2024 23:17:43 -0500 X-MC-Unique: 1j3nIyv_Pci_P4-hYm_S3A-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DA4961C07F2B; Fri, 26 Jan 2024 04:17:42 +0000 (UTC) Received: from x1n.redhat.com (unknown [10.72.116.11]) by smtp.corp.redhat.com (Postfix) with ESMTP id CBF83492BC6; Fri, 26 Jan 2024 04:17:40 +0000 (UTC) From: peterx@redhat.com To: qemu-devel@nongnu.org Cc: Fabiano Rosas , peterx@redhat.com Subject: [PULL 04/15] migration: Drop unnecessary check in ram's pending_exact() Date: Fri, 26 Jan 2024 12:17:14 +0800 Message-ID: <20240126041725.124562-5-peterx@redhat.com> In-Reply-To: <20240126041725.124562-1-peterx@redhat.com> References: <20240126041725.124562-1-peterx@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.5, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Peter Xu When the migration frameworks fetches the exact pending sizes, it means this check: remaining_size < s->threshold_size Must have been done already, actually at migration_iteration_run(): if (must_precopy <= s->threshold_size) { qemu_savevm_state_pending_exact(&must_precopy, &can_postcopy); That should be after one round of ram_state_pending_estimate(). It makes the 2nd check meaningless and can be dropped. To say it in another way, when reaching ->state_pending_exact(), we unconditionally sync dirty bits for precopy. Then we can drop migrate_get_current() there too. Reviewed-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240117075848.139045-3-peterx@redhat.com Signed-off-by: Peter Xu --- migration/ram.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index c0cdcccb75..d5b7cd5ac2 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3213,21 +3213,20 @@ static void ram_state_pending_estimate(void *opaque, uint64_t *must_precopy, static void ram_state_pending_exact(void *opaque, uint64_t *must_precopy, uint64_t *can_postcopy) { - MigrationState *s = migrate_get_current(); RAMState **temp = opaque; RAMState *rs = *temp; + uint64_t remaining_size; - uint64_t remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE; - - if (!migration_in_postcopy() && remaining_size < s->threshold_size) { + if (!migration_in_postcopy()) { bql_lock(); WITH_RCU_READ_LOCK_GUARD() { migration_bitmap_sync_precopy(rs, false); } bql_unlock(); - remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE; } + remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE; + if (migrate_postcopy_ram()) { /* We can do postcopy, and all the data is postcopiable */ *can_postcopy += remaining_size;