From patchwork Tue Apr 19 14:20:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liang Li X-Patchwork-Id: 8880811 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 81F80BF29F for ; Tue, 19 Apr 2016 14:30:18 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E0560202B8 for ; Tue, 19 Apr 2016 14:30:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8510202AE for ; Tue, 19 Apr 2016 14:30:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932139AbcDSOaH (ORCPT ); Tue, 19 Apr 2016 10:30:07 -0400 Received: from mga01.intel.com ([192.55.52.88]:13911 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754216AbcDSOaG (ORCPT ); Tue, 19 Apr 2016 10:30:06 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP; 19 Apr 2016 07:30:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,506,1455004800"; d="scan'208";a="948421690" Received: from ll.sh.intel.com (HELO localhost) ([10.239.13.27]) by fmsmga001.fm.intel.com with ESMTP; 19 Apr 2016 07:30:02 -0700 From: Liang Li To: mst@redhat.com, quintela@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, lcapitulino@redhat.com Cc: armbru@redhat.com, peter.maydell@linaro.org, rth@twiddle.net, ehabkost@redhat.com, james.hogan@imgtec.com, aurelien@aurel32.net, leon.alrae@imgtec.com, agraf@suse.de, borntraeger@de.ibm.com, cornelia.huck@de.ibm.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, Liang Li Subject: [PATCH QEMU 4/5] migration: filter out free pages during live migration Date: Tue, 19 Apr 2016 22:20:42 +0800 Message-Id: <1461075643-3668-5-git-send-email-liang.z.li@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1461075643-3668-1-git-send-email-liang.z.li@intel.com> References: <1461075643-3668-1-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-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.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 | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) diff --git a/migration/ram.c b/migration/ram.c index 3f05738..3944426 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -41,6 +41,8 @@ #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, ...) \ @@ -226,6 +228,8 @@ 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; +static bool drop_page_cache; /* used by the search for pages to send */ struct PageSearchStatus { @@ -242,6 +246,7 @@ 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 +644,7 @@ 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 +1423,9 @@ static void migration_bitmap_free(struct BitmapRcu *bmap) { g_free(bmap->bmap); g_free(bmap->unsentmap); + if (balloon_free_pages_support() && !migrate_postcopy_ram()) { + g_free(bmap->free_page_bmap); + } g_free(bmap); } @@ -1487,6 +1496,90 @@ 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) +{ + FreePageStatus status; + + /* drop_page_cache should be set by user, the related code will be + * added later, set it to ture temporarily. + */ + drop_page_cache = true; + + status = balloon_get_free_pages(bmap, max_pfn, drop_page_cache); + switch (status) { + case FREE_PAGE_REQ: + ignore_freepage_rsp = false; + break; + case FREE_PAGE_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; + FreePageStatus status; + + status = balloon_get_free_pages(migration_bitmap_rcu->free_page_bmap, + get_guest_max_pfn(), drop_page_cache); + switch (status) { + case FREE_PAGE_READY: + 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 FREE_PAGE_ERROR: + ignore_freepage_rsp = true; + error_report("failed to get free page"); + break; + case FREE_PAGE_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 +2043,11 @@ 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 +2088,9 @@ 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) {