From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:58208) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UGXDs-0001ZK-HS for qemu-devel@nongnu.org; Fri, 15 Mar 2013 12:11:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UGXDl-0006IG-Lt for qemu-devel@nongnu.org; Fri, 15 Mar 2013 12:11:12 -0400 Received: from [2a02:248:0:30:223:aeff:fefe:7f1c] (port=48335 helo=dns.kamp-intra.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UGXDl-0006Gz-F6 for qemu-devel@nongnu.org; Fri, 15 Mar 2013 12:11:05 -0400 From: Peter Lieven Date: Fri, 15 Mar 2013 16:50:16 +0100 Message-Id: <1363362619-3190-8-git-send-email-pl@kamp.de> In-Reply-To: <1363362619-3190-1-git-send-email-pl@kamp.de> References: <1363362619-3190-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCHv2 7/9] migration: do not sent zero pages in bulk stage List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Lieven 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 receival 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 | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch_init.c b/arch_init.c index e5531e8..a3dc20d 100644 --- a/arch_init.c +++ b/arch_init.c @@ -432,9 +432,11 @@ static int ram_save_block(QEMUFile *f, bool last_stage) bytes_sent = -1; if (buffer_is_zero(p, TARGET_PAGE_SIZE)) { acct_info.dup_pages++; - bytes_sent = save_block_hdr(f, block, offset, cont, - RAM_SAVE_FLAG_COMPRESS); - qemu_put_byte(f, *p); + if (!ram_bulk_stage) { + bytes_sent = save_block_hdr(f, block, offset, cont, + RAM_SAVE_FLAG_COMPRESS); + qemu_put_byte(f, *p); + } bytes_sent += 1; } else if (migrate_use_xbzrle()) { current_addr = block->offset + offset; -- 1.7.9.5