From patchwork Thu Mar 21 15:57:35 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 229743 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 7C3882C00C4 for ; Fri, 22 Mar 2013 03:00:36 +1100 (EST) Received: from localhost ([::1]:47649 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhus-0001le-NQ for incoming@patchwork.ozlabs.org; Thu, 21 Mar 2013 12:00:34 -0400 Received: from eggs.gnu.org ([208.118.235.92]:38579) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhsU-0006li-SF for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:58:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UIhsP-0002jv-0F for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:58:06 -0400 Received: from [2a02:248:0:30:223:aeff:fefe:7f1c] (port=33571 helo=dns.kamp-intra.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIhsO-0002je-R6 for qemu-devel@nongnu.org; Thu, 21 Mar 2013 11:58:00 -0400 Received: from lieven-pc.kamp-intra.net (lieven-pc.kamp-intra.net [172.21.12.60]) by dns.kamp-intra.net (Postfix) with ESMTP id 422B3206B1; Thu, 21 Mar 2013 16:58:00 +0100 (CET) Received: by lieven-pc.kamp-intra.net (Postfix, from userid 1000) id EE6205FCAE; Thu, 21 Mar 2013 16:58:10 +0100 (CET) From: Peter Lieven To: qemu-devel@nongnu.org Date: Thu, 21 Mar 2013 16:57:35 +0100 Message-Id: <1363881457-14814-8-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1363881457-14814-1-git-send-email-pl@kamp.de> References: <1363881457-14814-1-git-send-email-pl@kamp.de> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 2a02:248:0:30:223:aeff:fefe:7f1c Cc: kwolf@redhat.com, pbonzini@redhat.com, Peter Lieven Subject: [Qemu-devel] [PATCHv3 7/9] migration: do not sent zero pages in bulk stage X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 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 during bulk stage of ram migration if a page is a zero page do not send it at all. the memory at the destination reads as zero anyway. even if there is an madvise with QEMU_MADV_DONTNEED at the target upon receipt of a zero page I have observed that the target starts swapping if the memory is overcommitted. it seems that the pages are dropped asynchronously. Signed-off-by: Peter Lieven --- arch_init.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch_init.c b/arch_init.c index 2b59454..c2cb40a 100644 --- a/arch_init.c +++ b/arch_init.c @@ -438,10 +438,12 @@ static int ram_save_block(QEMUFile *f, bool last_stage) bytes_sent = -1; if (is_zero_page(p)) { acct_info.dup_pages++; - bytes_sent = save_block_hdr(f, block, offset, cont, - RAM_SAVE_FLAG_COMPRESS); - qemu_put_byte(f, *p); - bytes_sent += 1; + if (!ram_bulk_stage) { + bytes_sent = save_block_hdr(f, block, offset, cont, + RAM_SAVE_FLAG_COMPRESS); + qemu_put_byte(f, 0); + } + bytes_sent++; } else if (migrate_use_xbzrle()) { current_addr = block->offset + offset; bytes_sent = save_xbzrle_page(f, p, current_addr, block,