From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36922) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1evmu7-0008Vm-D8 for qemu-devel@nongnu.org; Tue, 13 Mar 2018 12:36:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1evmu4-0004JR-6E for qemu-devel@nongnu.org; Tue, 13 Mar 2018 12:35:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39890) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1evmu3-0004J0-UC for qemu-devel@nongnu.org; Tue, 13 Mar 2018 12:35:56 -0400 Date: Tue, 13 Mar 2018 18:35:36 +0200 From: "Michael S. Tsirkin" Message-ID: <20180313183050-mutt-send-email-mst@kernel.org> References: <1520426065-40265-1-git-send-email-wei.w.wang@intel.com> <1520426065-40265-5-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1520426065-40265-5-git-send-email-wei.w.wang@intel.com> Subject: Re: [Qemu-devel] [PATCH v4 4/4] migration: use the free page hint feature from balloon List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wei Wang Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, quintela@redhat.com, dgilbert@redhat.com, pbonzini@redhat.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com On Wed, Mar 07, 2018 at 08:34:25PM +0800, Wei Wang wrote: > Start the free page optimization after the migration bitmap is > synchronized. This can't be used in the stop© phase since the guest > is paused. Make sure the guest reporting has stopped before > synchronizing the migration dirty bitmap. Currently, the optimization is > added to precopy only. > > Signed-off-by: Wei Wang > CC: Dr. David Alan Gilbert > CC: Juan Quintela > CC: Michael S. Tsirkin > --- > migration/ram.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/migration/ram.c b/migration/ram.c > index e172798..7b4c9b1 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -51,6 +51,8 @@ > #include "qemu/rcu_queue.h" > #include "migration/colo.h" > #include "migration/block.h" > +#include "sysemu/balloon.h" > +#include "sysemu/sysemu.h" > > /***********************************************************/ > /* ram save/restore */ > @@ -208,6 +210,8 @@ struct RAMState { > uint32_t last_version; > /* We are in the first round */ > bool ram_bulk_stage; > + /* The free pages optimization feature is supported */ > + bool free_page_support; > /* How many times we have dirty too many pages */ > int dirty_rate_high_cnt; > /* these variables are used for bitmap sync */ > @@ -775,7 +779,7 @@ unsigned long migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb, > unsigned long *bitmap = rb->bmap; > unsigned long next; > > - if (rs->ram_bulk_stage && start > 0) { > + if (rs->ram_bulk_stage && start > 0 && !rs->free_page_support) { > next = start + 1; > } else { > next = find_next_bit(bitmap, size, start); > @@ -833,6 +837,10 @@ static void migration_bitmap_sync(RAMState *rs) > int64_t end_time; > uint64_t bytes_xfer_now; > > + if (rs->free_page_support) { > + balloon_free_page_stop(); > + } > + > ram_counters.dirty_sync_count++; > > if (!rs->time_last_bitmap_sync) { > @@ -899,6 +907,10 @@ static void migration_bitmap_sync(RAMState *rs) > if (migrate_use_events()) { > qapi_event_send_migration_pass(ram_counters.dirty_sync_count, NULL); > } > + > + if (rs->free_page_support && runstate_is_running()) { > + balloon_free_page_start(); > + } > } I think some of these conditions should go into balloon_free_page_start/stop. Checking runstate is generally problematic unless you also handle run state change notifiers as it can be manipulated from QMP. > > /** > @@ -1656,6 +1668,8 @@ static void ram_state_reset(RAMState *rs) > rs->last_page = 0; > rs->last_version = ram_list.version; > rs->ram_bulk_stage = true; > + rs->free_page_support = balloon_free_page_support() & > + !migration_in_postcopy(); Probably &&? > } > > #define MAX_WAIT 50 /* ms, half buffered_file limit */ > @@ -2330,6 +2344,9 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) > > ret = qemu_file_get_error(f); > if (ret < 0) { > + if (rs->free_page_support) { > + balloon_free_page_stop(); > + } > return ret; > } > > -- > 1.8.3.1