From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37015) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIkEs-0006lq-S7 for qemu-devel@nongnu.org; Thu, 21 Mar 2013 14:29:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UIk1B-0005VQ-9d for qemu-devel@nongnu.org; Thu, 21 Mar 2013 14:15:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39030) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIju0-0002Oy-W0 for qemu-devel@nongnu.org; Thu, 21 Mar 2013 14:07:49 -0400 Message-ID: <514B4CBA.9090803@redhat.com> Date: Thu, 21 Mar 2013 20:08:58 +0200 From: Orit Wasserman MIME-Version: 1.0 References: <1363881940-27505-1-git-send-email-owasserm@redhat.com> <1363881940-27505-9-git-send-email-owasserm@redhat.com> <87mwtwpsce.fsf@elfo.elfo> In-Reply-To: <87mwtwpsce.fsf@elfo.elfo> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 8/9] Use qemu_put_buffer_no_copy for guest memory pages List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: quintela@redhat.com Cc: pbonzini@redhat.com, chegu_vinod@hp.com, qemu-devel@nongnu.org, mst@redhat.com On 03/21/2013 07:37 PM, Juan Quintela wrote: > Orit Wasserman wrote: >> This will remove an unneeded copy of guest memory pages. >> For the page header and device state we still copy the data to the >> static buffer the other option is to allocate the memory on demand >> which is more expensive. >> >> Signed-off-by: Orit Wasserman >> --- >> arch_init.c | 2 +- >> savevm.c | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch_init.c b/arch_init.c >> index 98e2bc6..27b53eb 100644 >> --- a/arch_init.c >> +++ b/arch_init.c >> @@ -481,7 +481,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage) >> /* XBZRLE overflow or normal page */ >> if (bytes_sent == -1) { >> bytes_sent = save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_PAGE); >> - qemu_put_buffer(f, p, TARGET_PAGE_SIZE); >> + qemu_put_buffer_no_copy(f, p, TARGET_PAGE_SIZE); >> bytes_sent += TARGET_PAGE_SIZE; >> acct_info.norm_pages++; >> } > > Once here, shouldn't we also change: > > block-migration.c::blk_send() > > qemu_put_buffer(f, blk->buf, BLOCK_SIZE); > > to nocopy? Sadly no, I looked at the code and I saw the buffer is freed immediately after call blk_send :(. look at mig_save_device_dirty. Orit > > Again, this can be an additional patch. > > >> diff --git a/savevm.c b/savevm.c >> index fbfb9e3..50e8fb2 100644 >> --- a/savevm.c >> +++ b/savevm.c >> @@ -634,7 +634,7 @@ void qemu_put_buffer_no_copy(QEMUFile *f, const uint8_t *buf, int size) >> abort(); >> } >> >> - f->iov[f->iovcnt].iov_base = f->buf + f->buf_index; >> + f->iov[f->iovcnt].iov_base = (uint8_t *)buf; >> f->iov[f->iovcnt++].iov_len = size; > > This bit should be in the previous patch, the error that I pointed? > > Later, Juan. >