From ea016aa3636ce101148bb6246d86474fc1cdcbf8 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Wed, 1 Aug 2018 13:55:12 +0100 Subject: [PATCH 08/21] migration: move calling save_zero_page to the common place RH-Author: Dr. David Alan Gilbert Message-id: <20180801135522.11658-9-dgilbert@redhat.com> Patchwork-id: 81582 O-Subject: [qemu-kvm RHEL8/virt212 PATCH 08/18] migration: move calling save_zero_page to the common place Bugzilla: 1594384 RH-Acked-by: Peter Xu RH-Acked-by: John Snow RH-Acked-by: Juan Quintela From: Xiao Guangrong save_zero_page() is always our first approach to try, move it to the common place before calling ram_save_compressed_page and ram_save_page Reviewed-by: Peter Xu Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Xiao Guangrong Message-Id: <20180330075128.26919-9-xiaoguangrong@tencent.com> Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit d7400a3409982a52ac451cd3ca9caee9db670ca7) Signed-off-by: Danilo C. L. de Paula --- migration/ram.c | 105 +++++++++++++++++++++++++++++++------------------------- 1 file changed, 59 insertions(+), 46 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 9d6c41c..6e8a7e2 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1039,15 +1039,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage) trace_ram_save_page(block->idstr, (uint64_t)offset, p); XBZRLE_cache_lock(); - pages = save_zero_page(rs, block, offset); - if (pages > 0) { - /* Must let xbzrle know, otherwise a previous (now 0'd) cached - * page would be stale - */ - xbzrle_cache_zero_page(rs, current_addr); - ram_release_pages(block->idstr, offset, pages); - } else if (!rs->ram_bulk_stage && - !migration_in_postcopy() && migrate_use_xbzrle()) { + if (!rs->ram_bulk_stage && !migration_in_postcopy() && + migrate_use_xbzrle()) { pages = save_xbzrle_page(rs, &p, current_addr, block, offset, last_stage); if (!last_stage) { @@ -1195,40 +1188,23 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss, p = block->host + offset; - /* When starting the process of a new block, the first page of - * the block should be sent out before other pages in the same - * block, and all the pages in last block should have been sent - * out, keeping this order is important, because the 'cont' flag - * is used to avoid resending the block name. - */ if (block != rs->last_sent_block) { - flush_compressed_data(rs); - pages = save_zero_page(rs, block, offset); - if (pages > 0) { - ram_release_pages(block->idstr, offset, pages); - } else { - /* - * Make sure the first page is sent out before other pages. - * - * we post it as normal page as compression will take much - * CPU resource. - */ - ram_counters.transferred += save_page_header(rs, rs->f, block, - offset | RAM_SAVE_FLAG_PAGE); - qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE, - migrate_release_ram() & - migration_in_postcopy()); - ram_counters.transferred += TARGET_PAGE_SIZE; - ram_counters.normal++; - pages = 1; - } + /* + * Make sure the first page is sent out before other pages. + * + * we post it as normal page as compression will take much + * CPU resource. + */ + ram_counters.transferred += save_page_header(rs, rs->f, block, + offset | RAM_SAVE_FLAG_PAGE); + qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE, + migrate_release_ram() & + migration_in_postcopy()); + ram_counters.transferred += TARGET_PAGE_SIZE; + ram_counters.normal++; + pages = 1; } else { - pages = save_zero_page(rs, block, offset); - if (pages == -1) { - pages = compress_page_with_multi_thread(rs, block, offset); - } else { - ram_release_pages(block->idstr, offset, pages); - } + pages = compress_page_with_multi_thread(rs, block, offset); } return pages; @@ -1470,6 +1446,24 @@ err: return -1; } +static bool save_page_use_compression(RAMState *rs) +{ + if (!migrate_use_compression()) { + return false; + } + + /* + * If xbzrle is on, stop using the data compression after first + * round of migration even if compression is enabled. In theory, + * xbzrle can do better than compression. + */ + if (rs->ram_bulk_stage || !migrate_use_xbzrle()) { + return true; + } + + return false; +} + /** * ram_save_target_page: save one target page * @@ -1491,12 +1485,31 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss, } /* - * If xbzrle is on, stop using the data compression after first - * round of migration even if compression is enabled. In theory, - * xbzrle can do better than compression. + * When starting the process of a new block, the first page of + * the block should be sent out before other pages in the same + * block, and all the pages in last block should have been sent + * out, keeping this order is important, because the 'cont' flag + * is used to avoid resending the block name. */ - if (migrate_use_compression() && - (rs->ram_bulk_stage || !migrate_use_xbzrle())) { + if (block != rs->last_sent_block && save_page_use_compression(rs)) { + flush_compressed_data(rs); + } + + res = save_zero_page(rs, block, offset); + if (res > 0) { + /* Must let xbzrle know, otherwise a previous (now 0'd) cached + * page would be stale + */ + if (!save_page_use_compression(rs)) { + XBZRLE_cache_lock(); + xbzrle_cache_zero_page(rs, block->offset + offset); + XBZRLE_cache_unlock(); + } + ram_release_pages(block->idstr, offset, res); + return res; + } + + if (save_page_use_compression(rs)) { return ram_save_compressed_page(rs, pss, last_stage); } -- 1.8.3.1