From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60494) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1erfhT-0002xw-L5 for qemu-devel@nongnu.org; Fri, 02 Mar 2018 03:05:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1erfhO-00018F-Ni for qemu-devel@nongnu.org; Fri, 02 Mar 2018 03:05:55 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55678 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1erfhO-00017k-90 for qemu-devel@nongnu.org; Fri, 02 Mar 2018 03:05:50 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C81358D6EF for ; Fri, 2 Mar 2018 08:05:39 +0000 (UTC) Date: Fri, 2 Mar 2018 16:05:24 +0800 From: Peter Xu Message-ID: <20180302080524.GO27381@xz-mi> References: <20180216131625.9639-1-dgilbert@redhat.com> <20180216131625.9639-23-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180216131625.9639-23-dgilbert@redhat.com> Subject: Re: [Qemu-devel] [PATCH v3 22/29] vhost+postcopy: Call wakeups List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" Cc: qemu-devel@nongnu.org, maxime.coquelin@redhat.com, marcandre.lureau@redhat.com, imammedo@redhat.com, mst@redhat.com, quintela@redhat.com, aarcange@redhat.com On Fri, Feb 16, 2018 at 01:16:18PM +0000, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" > > Cause the vhost-user client to be woken up whenever: > a) We place a page in postcopy mode > b) We get a fault and the page has already been received > > Signed-off-by: Dr. David Alan Gilbert > --- > migration/postcopy-ram.c | 14 ++++++++++---- > migration/trace-events | 1 + > 2 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index 879711968c..13561703b5 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -566,7 +566,11 @@ int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, > > trace_postcopy_request_shared_page(pcfd->idstr, qemu_ram_get_idstr(rb), > rb_offset); > - /* TODO: Check bitmap to see if we already have the page */ > + if (ramblock_recv_bitmap_test_byte_offset(rb, aligned_rbo)) { > + trace_postcopy_request_shared_page_present(pcfd->idstr, > + qemu_ram_get_idstr(rb), rb_offset); > + return postcopy_wake_shared(pcfd, client_addr, rb); > + } > if (rb != mis->last_rb) { > mis->last_rb = rb; > migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), > @@ -863,7 +867,8 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, > } > > trace_postcopy_place_page(host); > - return 0; > + return postcopy_notify_shared_wake(rb, > + qemu_ram_block_host_offset(rb, host)); > } > > /* > @@ -887,6 +892,9 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, > > return -e; > } > + return postcopy_notify_shared_wake(rb, > + qemu_ram_block_host_offset(rb, > + host)); > } else { > /* The kernel can't use UFFDIO_ZEROPAGE for hugepages */ > if (!mis->postcopy_tmp_zero_page) { > @@ -906,8 +914,6 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, > return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page, > rb); > } > - > - return 0; > } Could there be race? E.g.: ram_load_thread page_fault_thread ----------------- ------------------- if (recv_bitmap_set()) wake() copy_page() recv_bitmap_set() wake() request_page() Then the last requested page may never be serviced? Thanks, -- Peter Xu