From nobody Thu Nov 6 21:16:33 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=intel.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1543805746222262.57943335187156; Sun, 2 Dec 2018 18:55:46 -0800 (PST) Received: from localhost ([::1]:46562 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gTeOf-00059Y-4B for importer@patchew.org; Sun, 02 Dec 2018 21:55:45 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49893) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gTeKh-0000uy-JU for qemu-devel@nongnu.org; Sun, 02 Dec 2018 21:51:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gTeKg-0000cS-Oe for qemu-devel@nongnu.org; Sun, 02 Dec 2018 21:51:39 -0500 Received: from mga07.intel.com ([134.134.136.100]:65450) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gTeKg-0000Zq-Fw for qemu-devel@nongnu.org; Sun, 02 Dec 2018 21:51:38 -0500 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Dec 2018 18:51:38 -0800 Received: from devel-ww.sh.intel.com ([10.239.48.119]) by FMSMGA003.fm.intel.com with ESMTP; 02 Dec 2018 18:51:36 -0800 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,308,1539673200"; d="scan'208";a="115254791" From: Wei Wang To: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com, peterx@redhat.com Date: Mon, 3 Dec 2018 10:18:28 +0800 Message-Id: <1543803511-34793-5-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1543803511-34793-1-git-send-email-wei.w.wang@intel.com> References: <1543803511-34793-1-git-send-email-wei.w.wang@intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.100 Subject: [Qemu-devel] [PATCH v10 4/7] migration: API to clear bits of guest free pages from the dirty bitmap X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, liliang.opensource@gmail.com, nilal@redhat.com, wei.w.wang@intel.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This patch adds an API to clear bits corresponding to guest free pages from the dirty bitmap. Spilt the free page block if it crosses the QEMU RAMBlock boundary. Signed-off-by: Wei Wang CC: Dr. David Alan Gilbert CC: Juan Quintela CC: Michael S. Tsirkin CC: Peter Xu Reviewed-by: Peter Xu --- include/migration/misc.h | 2 ++ migration/ram.c | 47 ++++++++++++++++++++++++++++++++++++++++++++= +++ 2 files changed, 49 insertions(+) diff --git a/include/migration/misc.h b/include/migration/misc.h index 4ebf24c..113320e 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -14,11 +14,13 @@ #ifndef MIGRATION_MISC_H #define MIGRATION_MISC_H =20 +#include "exec/cpu-common.h" #include "qemu/notify.h" =20 /* migration/ram.c */ =20 void ram_mig_init(void); +void qemu_guest_free_page_hint(void *addr, size_t len); =20 /* migration/block.c */ =20 diff --git a/migration/ram.c b/migration/ram.c index 01d267f..4f7a3fe 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3131,6 +3131,53 @@ static void ram_state_resume_prepare(RAMState *rs, Q= EMUFile *out) } =20 /* + * This function clears bits of the free pages reported by the caller from= the + * migration dirty bitmap. @addr is the host address corresponding to the + * start of the continuous guest free pages, and @len is the total bytes of + * those pages. + */ +void qemu_guest_free_page_hint(void *addr, size_t len) +{ + RAMBlock *block; + ram_addr_t offset; + size_t used_len, start, npages; + MigrationState *s =3D migrate_get_current(); + + /* This function is currently expected to be used during live migratio= n */ + if (!migration_is_setup_or_active(s->state)) { + return; + } + + for (; len > 0; len -=3D used_len, addr +=3D used_len) { + block =3D qemu_ram_block_from_host(addr, false, &offset); + if (unlikely(!block || offset > block->used_length)) { + /* + * The implementation might not support RAMBlock resize during + * live migration, but it could happen in theory with future + * updates. So we add a check here to capture that case. + */ + error_report_once("%s unexpected error", __func__); + return; + } + + if (len <=3D block->used_length - offset) { + used_len =3D len; + } else { + used_len =3D block->used_length - offset; + } + + start =3D offset >> TARGET_PAGE_BITS; + npages =3D used_len >> TARGET_PAGE_BITS; + + qemu_mutex_lock(&ram_state->bitmap_mutex); + ram_state->migration_dirty_pages -=3D + bitmap_count_one_with_offset(block->bmap, start, npa= ges); + bitmap_clear(block->bmap, start, npages); + qemu_mutex_unlock(&ram_state->bitmap_mutex); + } +} + +/* * Each of ram_save_setup, ram_save_iterate and ram_save_complete has * long-running RCU critical section. When rcu-reclaims in the code * start to become numerous it will be necessary to reduce the --=20 1.8.3.1