From patchwork Mon Jun 13 10:16:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liang Li X-Patchwork-Id: 9172557 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BB8856086B for ; Mon, 13 Jun 2016 10:23:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AC13D22064 for ; Mon, 13 Jun 2016 10:23:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A0BD027C8F; Mon, 13 Jun 2016 10:23:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1CAB427BC3 for ; Mon, 13 Jun 2016 10:23:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161137AbcFMKXW (ORCPT ); Mon, 13 Jun 2016 06:23:22 -0400 Received: from mga11.intel.com ([192.55.52.93]:58122 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161154AbcFMKXU (ORCPT ); Mon, 13 Jun 2016 06:23:20 -0400 Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP; 13 Jun 2016 03:23:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,466,1459839600"; d="scan'208";a="996462783" Received: from ll.sh.intel.com (HELO localhost) ([10.239.13.123]) by orsmga002.jf.intel.com with ESMTP; 13 Jun 2016 03:23:18 -0700 From: Liang Li To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, mst@redhat.com, lcapitulino@redhat.com, pbonzini@redhat.com, quintela@redhat.com, amit.shah@redhat.com, dgilbert@redhat.com, Liang Li Subject: [QEMU 7/7] migration: skip free pages during live migration Date: Mon, 13 Jun 2016 18:16:49 +0800 Message-Id: <1465813009-21390-8-git-send-email-liang.z.li@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1465813009-21390-1-git-send-email-liang.z.li@intel.com> References: <1465813009-21390-1-git-send-email-liang.z.li@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP After sending out the request for free pages, live migration process will start without waiting for the free page bitmap is ready. If the free page bitmap is not ready when doing the 1st migration_bitmap_sync() after ram_save_setup(), the free page bitmap will be ignored, this means the free pages will not be filtered out in this case. The current implementation can not work with post copy, if post copy is enabled, we simply ignore the free pages. Will make it work later. Signed-off-by: Liang Li --- migration/ram.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) diff --git a/migration/ram.c b/migration/ram.c index 844ea46..5f1c3ff 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -43,6 +43,8 @@ #include "trace.h" #include "exec/ram_addr.h" #include "qemu/rcu_queue.h" +#include "sysemu/balloon.h" +#include "sysemu/kvm.h" #ifdef DEBUG_MIGRATION_RAM #define DPRINTF(fmt, ...) \ @@ -228,6 +230,7 @@ static QemuMutex migration_bitmap_mutex; static uint64_t migration_dirty_pages; static uint32_t last_version; static bool ram_bulk_stage; +static bool ignore_freepage_rsp; /* used by the search for pages to send */ struct PageSearchStatus { @@ -244,6 +247,7 @@ static struct BitmapRcu { struct rcu_head rcu; /* Main migration bitmap */ unsigned long *bmap; + unsigned long *free_page_bmap; /* bitmap of pages that haven't been sent even once * only maintained and used in postcopy at the moment * where it's used to send the dirtymap at the start @@ -639,6 +643,7 @@ static void migration_bitmap_sync(void) rcu_read_unlock(); qemu_mutex_unlock(&migration_bitmap_mutex); + ignore_freepage_rsp = true; trace_migration_bitmap_sync_end(migration_dirty_pages - num_dirty_pages_init); num_dirty_pages_period += migration_dirty_pages - num_dirty_pages_init; @@ -1417,6 +1422,7 @@ static void migration_bitmap_free(struct BitmapRcu *bmap) { g_free(bmap->bmap); g_free(bmap->unsentmap); + g_free(bmap->free_page_bmap); g_free(bmap); } @@ -1487,6 +1493,85 @@ void migration_bitmap_extend(ram_addr_t old, ram_addr_t new) } } +static void filter_out_guest_free_page(unsigned long *free_page_bmap, + long nbits) +{ + long i, page_count = 0, len; + unsigned long *bitmap; + + tighten_guest_free_page_bmap(free_page_bmap); + qemu_mutex_lock(&migration_bitmap_mutex); + bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap; + slow_bitmap_complement(bitmap, free_page_bmap, nbits); + + len = (last_ram_offset() >> TARGET_PAGE_BITS) / BITS_PER_LONG; + for (i = 0; i < len; i++) { + page_count += hweight_long(bitmap[i]); + } + + migration_dirty_pages = page_count; + qemu_mutex_unlock(&migration_bitmap_mutex); +} + +static void ram_request_free_page(unsigned long *bmap, unsigned long max_pfn) +{ + BalloonReqStatus status; + + status = balloon_get_free_pages(bmap, max_pfn); + switch (status) { + case REQ_DONE: + ignore_freepage_rsp = false; + break; + case REQ_ERROR: + error_report("Errro happend when request free page"); + break; + default: + error_report("unexpected response status: %d", status); + break; + } +} + +static void ram_handle_free_page(void) +{ + unsigned long nbits; + RAMBlock *pc_ram_block; + BalloonReqStatus status; + + status = balloon_get_free_pages(migration_bitmap_rcu->free_page_bmap, + get_guest_max_pfn()); + switch (status) { + case REQ_DONE: + rcu_read_lock(); + pc_ram_block = QLIST_FIRST_RCU(&ram_list.blocks); + nbits = pc_ram_block->used_length >> TARGET_PAGE_BITS; + filter_out_guest_free_page(migration_bitmap_rcu->free_page_bmap, nbits); + rcu_read_unlock(); + + qemu_mutex_lock_iothread(); + migration_bitmap_sync(); + qemu_mutex_unlock_iothread(); + /* + * bulk stage assumes in (migration_bitmap_find_and_reset_dirty) that + * every page is dirty, that's no longer ture at this point. + */ + ram_bulk_stage = false; + last_seen_block = NULL; + last_sent_block = NULL; + last_offset = 0; + break; + case REQ_ERROR: + ignore_freepage_rsp = true; + error_report("failed to get free page"); + break; + case REQ_INVALID_PARAM: + ignore_freepage_rsp = true; + error_report("buffer overflow"); + break; + default: + break; + } +} + /* * 'expected' is the value you expect the bitmap mostly to be full * of; it won't bother printing lines that are all this value. @@ -1950,6 +2035,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque) qemu_mutex_unlock_ramlist(); qemu_mutex_unlock_iothread(); + if (balloon_free_pages_support() && !migrate_postcopy_ram()) { + unsigned long max_pfn = get_guest_max_pfn(); + migration_bitmap_rcu->free_page_bmap = bitmap_new(max_pfn); + ram_request_free_page(migration_bitmap_rcu->free_page_bmap, max_pfn); + } qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE); QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { @@ -1990,6 +2080,9 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) while ((ret = qemu_file_rate_limit(f)) == 0) { int pages; + if (!ignore_freepage_rsp) { + ram_handle_free_page(); + } pages = ram_find_and_save_block(f, false, &bytes_transferred); /* no more pages to sent */ if (pages == 0) {