From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54245) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fj7q2-0008O6-57 for qemu-devel@nongnu.org; Fri, 27 Jul 2018 14:51:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fj7px-0005Gg-Ep for qemu-devel@nongnu.org; Fri, 27 Jul 2018 14:51:42 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43564 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 1fj7px-0005ET-8P for qemu-devel@nongnu.org; Fri, 27 Jul 2018 14:51:37 -0400 Date: Fri, 27 Jul 2018 19:51:32 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180727185131.GD2498@work-vm> References: <20180722193350.6028-1-zhangckid@gmail.com> <20180722193350.6028-9-zhangckid@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180722193350.6028-9-zhangckid@gmail.com> Subject: Re: [Qemu-devel] [PATCH V10 08/20] ram/COLO: Record the dirty pages that SVM received List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Zhang Chen Cc: qemu-devel@nongnu.org, Paolo Bonzini , Juan Quintela , Jason Wang , Eric Blake , Markus Armbruster , zhanghailiang , Li Zhijian * Zhang Chen (zhangckid@gmail.com) wrote: > We record the address of the dirty pages that received, > it will help flushing pages that cached into SVM. > > Here, it is a trick, we record dirty pages by re-using migration > dirty bitmap. In the later patch, we will start the dirty log > for SVM, just like migration, in this way, we can record both > the dirty pages caused by PVM and SVM, we only flush those dirty > pages from RAM cache while do checkpoint. > > Signed-off-by: zhanghailiang > Reviewed-by: Dr. David Alan Gilbert > --- > migration/ram.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/migration/ram.c b/migration/ram.c > index 33ebd09d70..d1060f1337 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -3325,6 +3325,15 @@ static inline void *colo_cache_from_block_offset(RAMBlock *block, > __func__, block->idstr); > return NULL; > } > + > + /* > + * During colo checkpoint, we need bitmap of these migrated pages. > + * It help us to decide which pages in ram cache should be flushed > + * into VM's RAM later. > + */ > + if (!test_and_set_bit(offset >> TARGET_PAGE_BITS, block->bmap)) { > + ram_state->migration_dirty_pages++; > + } > return block->colo_cache + offset; > } > > @@ -3555,6 +3564,24 @@ int colo_init_ram_cache(void) > memcpy(block->colo_cache, block->host, block->used_length); > } > rcu_read_unlock(); > + /* > + * Record the dirty pages that sent by PVM, we use this dirty bitmap together > + * with to decide which page in cache should be flushed into SVM's RAM. Here > + * we use the same name 'ram_bitmap' as for migration. > + */ > + if (ram_bytes_total()) { > + RAMBlock *block; > + > + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { I think those need updating to check for 'qemu_ram_is_migratable' - it might be worth moving RAMBLOCK_FOREACH_MIGRATABLE. > + unsigned long pages = block->max_length >> TARGET_PAGE_BITS; > + > + block->bmap = bitmap_new(pages); > + bitmap_set(block->bmap, 0, pages); Would it make sense to use the 'receivedmap' that was recently added for other uses rather than needing your own? Dave > + } > + } > + ram_state = g_new0(RAMState, 1); > + ram_state->migration_dirty_pages = 0; > + > return 0; > > out_locked: > @@ -3574,6 +3601,10 @@ void colo_release_ram_cache(void) > { > RAMBlock *block; > > + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { > + g_free(block->bmap); > + block->bmap = NULL; > + } > rcu_read_lock(); > QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { > if (block->colo_cache) { > @@ -3582,6 +3613,8 @@ void colo_release_ram_cache(void) > } > } > rcu_read_unlock(); > + g_free(ram_state); > + ram_state = NULL; > } > > /** > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK