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[70.53.122.15]) by smtp.gmail.com with ESMTPSA id l38sm2319889qtl.58.2020.09.03.08.26.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2020 08:26:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599146820; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SN+zpDe63b9OXABJW135pgj4q08uRgy/TMocpHMnT88=; b=DzsB7784ZeG1akKNy10wM27wTNVSB2vHQuiAzU7IfGyPZycl95dK+h3gjjdXfMCagut1Gl 0QgvqF8bT/8ztcMPledpDVwykO0+87n53S2n1y/JxHz7xUyygDuhbGwAj4HRpGfv5uCc3z T6NQPVFnfRCQFYsL/olg44AR7vU+YmM= X-MC-Unique: nndpTprDPEWybfrL-1_LBQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=SN+zpDe63b9OXABJW135pgj4q08uRgy/TMocpHMnT88=; b=UzM8aa1dQX1ZYrQNqyi25p0qZUVbGmKYPoES+cLWpBg9NvSfg2CKQPJU29LLj/3MMr 6zw2facEVAs6PwW4nuoYLq068wCIJsbH5QJ7D4+NdZQUXY6aUho6QrvonEgNOKzhHH2O 1p7L7NgSXJzqAooK+1p920Xt7AFM0BvqUAxTzr64XIKXQOFsaixWGa35mUUlpfXySe93 9w3U/PTBHM6COyJ43NB/ldbktj/Zq9KguzAWrVBu3ODQbwhpnayasZ5U0RmzmnvRc8D7 HOZFg3wEJ/ZJLMI4lC66CzwPSTXvxDnTNEH3gjbrFjpYwTPh5hS4FWJEhRGmPrlOGCjp 4qsw== X-Gm-Message-State: AOAM533WrJ8SUrloNUZmTL0cxKsBxvAMY83yG5QlyFVoGp4xH3nWQjh9 q8JoXOUhIIyBDOvCm9rzXvjR8jmtVqH/GRmtIGPCi93S/PIW8T3Tgt1LDAqHEWMoTUBXexcrpSA 1BYIHd+wlDYQeMI8= X-Received: by 2002:a0c:de0f:: with SMTP id t15mr3449302qvk.90.1599146817095; Thu, 03 Sep 2020 08:26:57 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx5VWYzIE3WiP4K3dcvtkqv9LeAY2SZSUaV46AuCecyFjoS83lup39Dwj7+QPW8Xw1mFlzGaA== X-Received: by 2002:a0c:de0f:: with SMTP id t15mr3449277qvk.90.1599146816767; Thu, 03 Sep 2020 08:26:56 -0700 (PDT) From: Peter Xu To: qemu-devel@nongnu.org Subject: [PATCH 5/5] migration: Sync requested pages after postcopy recovery Date: Thu, 3 Sep 2020 11:26:46 -0400 Message-Id: <20200903152646.93336-6-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200903152646.93336-1-peterx@redhat.com> References: <20200903152646.93336-1-peterx@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=peterx@redhat.com X-Mimecast-Spam-Score: 0.003 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/03 04:23:54 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Xiaohui Li , "Dr . David Alan Gilbert" , peterx@redhat.com, Juan Quintela Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" We synchronize the requested pages right after a postcopy recovery happens. This helps to synchronize the prioritized pages on source so that the fault= ed threads can be served faster. Reported-by: Xiaohui Li Signed-off-by: Peter Xu Reviewed-by: Dr. David Alan Gilbert --- migration/savevm.c | 56 ++++++++++++++++++++++++++++++++++++++++++ migration/trace-events | 1 + 2 files changed, 57 insertions(+) diff --git a/migration/savevm.c b/migration/savevm.c index 304d98ff78..f998dd230d 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2011,6 +2011,48 @@ static int loadvm_postcopy_handle_run(MigrationIncom= ingState *mis) return LOADVM_QUIT; } =20 +/* We must be with page_request_mutex held */ +static gboolean postcopy_sync_page_req(gpointer key, gpointer value, + gpointer data) +{ + MigrationIncomingState *mis =3D data; + void *host_addr =3D (void *) key; + ram_addr_t rb_offset; + RAMBlock *rb; + int ret; + + rb =3D qemu_ram_block_from_host(host_addr, true, &rb_offset); + if (!rb) { + /* + * This should _never_ happen. However be nice for a migrating VM= to + * not crash/assert. Post an error (note: intended to not use *_o= nce + * because we do want to see all the illegal addresses; and this c= an + * never be triggered by the guest so we're safe) and move on next. + */ + error_report("%s: illegal host addr %p", __func__, host_addr); + /* Try the next entry */ + return FALSE; + } + + ret =3D migrate_send_rp_message_req_pages(mis, rb, rb_offset); + if (ret) { + /* Refer to above comment - just try our best to continue */ + error_report("%s: send rp message failed for addr %p", + __func__, host_addr); + } + + trace_postcopy_page_req_sync((uint64_t)host_addr); + + return FALSE; +} + +static void migrate_send_rp_req_pages_pending(MigrationIncomingState *mis) +{ + qemu_mutex_lock(&mis->page_request_mutex); + g_tree_foreach(mis->page_requested, postcopy_sync_page_req, mis); + qemu_mutex_unlock(&mis->page_request_mutex); +} + static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) { if (mis->state !=3D MIGRATION_STATUS_POSTCOPY_RECOVER) { @@ -2033,6 +2075,20 @@ static int loadvm_postcopy_handle_resume(MigrationIn= comingState *mis) /* Tell source that "we are ready" */ migrate_send_rp_resume_ack(mis, MIGRATION_RESUME_ACK_VALUE); =20 + /* + * After a postcopy recovery, the source should have lost the postcopy + * queue, or potentially the requested pages could have been lost duri= ng + * the network down phase. Let's re-sync with the source VM by re-sen= ding + * all the pending pages that we eagerly need, so these threads won't = get + * blocked too long due to the recovery. + * + * Without this procedure, the faulted destination VM threads (waiting= for + * page requests right before the postcopy is interrupted) can keep ha= nging + * until the pages are sent by the source during the background copyin= g of + * pages, or another thread faulted on the same address accidentally. + */ + migrate_send_rp_req_pages_pending(mis); + return 0; } =20 diff --git a/migration/trace-events b/migration/trace-events index b89ce02cb0..54a6dd2761 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -49,6 +49,7 @@ vmstate_save(const char *idstr, const char *vmsd_name) "%= s, %s" vmstate_load(const char *idstr, const char *vmsd_name) "%s, %s" postcopy_pause_incoming(void) "" postcopy_pause_incoming_continued(void) "" +postcopy_page_req_sync(uint64_t host_addr) "sync page req 0x%"PRIx64 =20 # vmstate.c vmstate_load_field_error(const char *field, int ret) "field \"%s\" load fa= iled, ret =3D %d" --=20 2.26.2