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GET /api/patches/810556/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 810556,
    "url": "http://patchwork.ozlabs.org/api/patches/810556/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170906115143.27451-23-quintela@redhat.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20170906115143.27451-23-quintela@redhat.com>",
    "list_archive_url": null,
    "date": "2017-09-06T11:51:43",
    "name": "[v7,22/22] migration: Flush receive queue",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "c15e9e5033e3856059e29e60dba5e145f4a9500a",
    "submitter": {
        "id": 2643,
        "url": "http://patchwork.ozlabs.org/api/people/2643/?format=api",
        "name": "Juan Quintela",
        "email": "quintela@redhat.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170906115143.27451-23-quintela@redhat.com/mbox/",
    "series": [
        {
            "id": 1773,
            "url": "http://patchwork.ozlabs.org/api/series/1773/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=1773",
            "date": "2017-09-06T11:51:21",
            "name": "Multifd",
            "version": 7,
            "mbox": "http://patchwork.ozlabs.org/series/1773/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/810556/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/810556/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org",
        "Authentication-Results": [
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            "ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com",
            "ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=quintela@redhat.com"
        ],
        "Received": [
            "from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xnMqD3dWgz9sBZ\n\tfor <incoming@patchwork.ozlabs.org>;\n\tWed,  6 Sep 2017 22:10:32 +1000 (AEST)",
            "from localhost ([::1]:35801 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dpZA6-0004fO-JW\n\tfor incoming@patchwork.ozlabs.org; Wed, 06 Sep 2017 08:10:30 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:60606)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <quintela@redhat.com>) id 1dpYsu-0007sn-1F\n\tfor qemu-devel@nongnu.org; Wed, 06 Sep 2017 07:52:45 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <quintela@redhat.com>) id 1dpYst-0008Id-0E\n\tfor qemu-devel@nongnu.org; Wed, 06 Sep 2017 07:52:44 -0400",
            "from mx1.redhat.com ([209.132.183.28]:34374)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <quintela@redhat.com>) id 1dpYss-0008Hw-O4\n\tfor qemu-devel@nongnu.org; Wed, 06 Sep 2017 07:52:42 -0400",
            "from smtp.corp.redhat.com\n\t(int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id BF6B381DEE\n\tfor <qemu-devel@nongnu.org>; Wed,  6 Sep 2017 11:52:41 +0000 (UTC)",
            "from secure.mitica (ovpn-117-188.ams2.redhat.com [10.36.117.188])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id 55E5F5C316;\n\tWed,  6 Sep 2017 11:52:40 +0000 (UTC)"
        ],
        "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com BF6B381DEE",
        "From": "Juan Quintela <quintela@redhat.com>",
        "To": "qemu-devel@nongnu.org",
        "Date": "Wed,  6 Sep 2017 13:51:43 +0200",
        "Message-Id": "<20170906115143.27451-23-quintela@redhat.com>",
        "In-Reply-To": "<20170906115143.27451-1-quintela@redhat.com>",
        "References": "<20170906115143.27451-1-quintela@redhat.com>",
        "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.11",
        "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.25]);\n\tWed, 06 Sep 2017 11:52:41 +0000 (UTC)",
        "X-detected-operating-system": "by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]",
        "X-Received-From": "209.132.183.28",
        "Subject": "[Qemu-devel] [PATCH v7 22/22] migration: Flush receive queue",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "<qemu-devel.nongnu.org>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Cc": "lvivier@redhat.com, dgilbert@redhat.com, peterx@redhat.com",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>"
    },
    "content": "Each time that we sync the bitmap, it is a possiblity that we receive\na page that is being processed by a different thread.  We fix this\nproblem just making sure that we wait for all receiving threads to\nfinish its work before we procedeed with the next stage.\n\nWe are low on page flags, so we use a combination that is not valid to\nemit that message:  MULTIFD_PAGE and COMPRESSED.\n\nI tried to make a migration command for it, but it don't work because\nwe sync the bitmap sometimes when we have already sent the beggining\nof the section, so I just added a new page flag.\n\nSigned-off-by: Juan Quintela <quintela@redhat.com>\n\n--\nCreate RAM_SAVE_FLAG_MULTIFD_SYNC (dave suggestion)\nMove the set of need_flush to inside the bitmap_sync code (peter suggestion)\n---\n migration/ram.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++\n 1 file changed, 54 insertions(+)",
    "diff": "diff --git a/migration/ram.c b/migration/ram.c\nindex 0c2782c452..295b6002ac 100644\n--- a/migration/ram.c\n+++ b/migration/ram.c\n@@ -71,6 +71,13 @@\n #define RAM_SAVE_FLAG_COMPRESS_PAGE    0x100\n #define RAM_SAVE_FLAG_MULTIFD_PAGE     0x200\n \n+/* We are getting low on pages flags, so we start using combinations\n+   When we need to flush a page, we sent it as\n+   RAM_SAVE_FLAG_MULTIFD_PAGE | RAM_SAVE_FLAG_COMPRESS_PAGE\n+   We don't allow that combination\n+*/\n+#define RAM_SAVE_FLAG_MULTIFD_SYNC (RAM_SAVE_FLAG_MULTIFD_PAGE | RAM_SAVE_FLAG_ZERO)\n+\n static inline bool is_zero_range(uint8_t *p, uint64_t size)\n {\n     return buffer_is_zero(p, size);\n@@ -193,6 +200,9 @@ struct RAMState {\n     uint64_t iterations_prev;\n     /* Iterations since start */\n     uint64_t iterations;\n+    /* Indicates if we have synced the bitmap and we need to assure that\n+       target has processeed all previous pages */\n+    bool multifd_needs_flush;\n     /* number of dirty bits in the bitmap */\n     uint64_t migration_dirty_pages;\n     /* protects modification of the bitmap */\n@@ -609,9 +619,11 @@ struct MultiFDRecvParams {\n     QIOChannel *c;\n     QemuSemaphore ready;\n     QemuSemaphore sem;\n+    QemuCond cond_sync;\n     QemuMutex mutex;\n     /* proteced by param mutex */\n     bool quit;\n+    bool sync;\n     multifd_pages_t pages;\n     bool done;\n };\n@@ -664,6 +676,7 @@ int multifd_load_cleanup(Error **errp)\n         qemu_thread_join(&p->thread);\n         qemu_mutex_destroy(&p->mutex);\n         qemu_sem_destroy(&p->sem);\n+        qemu_cond_destroy(&p->cond_sync);\n         socket_recv_channel_destroy(p->c);\n         g_free(p->name);\n         p->name = NULL;\n@@ -702,6 +715,10 @@ static void *multifd_recv_thread(void *opaque)\n                 return NULL;\n             }\n             p->done = true;\n+            if (p->sync) {\n+                qemu_cond_signal(&p->cond_sync);\n+                p->sync = false;\n+            }\n             qemu_mutex_unlock(&p->mutex);\n             qemu_sem_post(&p->ready);\n             continue;\n@@ -752,9 +769,11 @@ void multifd_new_channel(QIOChannel *ioc)\n     qemu_mutex_init(&p->mutex);\n     qemu_sem_init(&p->sem, 0);\n     qemu_sem_init(&p->ready, 0);\n+    qemu_cond_init(&p->cond_sync);\n     p->quit = false;\n     p->id = id;\n     p->done = false;\n+    p->sync = false;\n     multifd_init_group(&p->pages);\n     p->c = ioc;\n     multifd_recv_state->count++;\n@@ -814,6 +833,27 @@ static void multifd_recv_page(uint8_t *address, uint16_t fd_num)\n     qemu_sem_post(&p->sem);\n }\n \n+static int multifd_flush(void)\n+{\n+    int i, thread_count;\n+\n+    if (!migrate_use_multifd()) {\n+        return 0;\n+    }\n+    thread_count = migrate_multifd_threads();\n+    for (i = 0; i < thread_count; i++) {\n+        MultiFDRecvParams *p = &multifd_recv_state->params[i];\n+\n+        qemu_mutex_lock(&p->mutex);\n+        while (!p->done) {\n+            p->sync = true;\n+            qemu_cond_wait(&p->cond_sync, &p->mutex);\n+        }\n+        qemu_mutex_unlock(&p->mutex);\n+    }\n+    return 0;\n+}\n+\n /**\n  * save_page_header: write page header to wire\n  *\n@@ -831,6 +871,12 @@ static size_t save_page_header(RAMState *rs, QEMUFile *f,  RAMBlock *block,\n {\n     size_t size, len;\n \n+    if (rs->multifd_needs_flush &&\n+        (offset & RAM_SAVE_FLAG_MULTIFD_PAGE)) {\n+        offset |= RAM_SAVE_FLAG_ZERO;\n+        rs->multifd_needs_flush = false;\n+    }\n+\n     if (block == rs->last_sent_block) {\n         offset |= RAM_SAVE_FLAG_CONTINUE;\n     }\n@@ -1116,6 +1162,9 @@ static void migration_bitmap_sync(RAMState *rs)\n     if (migrate_use_events()) {\n         qapi_event_send_migration_pass(ram_counters.dirty_sync_count, NULL);\n     }\n+    if (!rs->ram_bulk_stage && migrate_use_multifd()) {\n+        rs->multifd_needs_flush = true;\n+    }\n }\n \n /**\n@@ -3034,6 +3083,11 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)\n             break;\n         }\n \n+        if ((flags & RAM_SAVE_FLAG_MULTIFD_SYNC)\n+            == RAM_SAVE_FLAG_MULTIFD_SYNC) {\n+            multifd_flush();\n+            flags = flags & ~RAM_SAVE_FLAG_ZERO;\n+        }\n         if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE |\n                      RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE |\n                      RAM_SAVE_FLAG_MULTIFD_PAGE)) {\n",
    "prefixes": [
        "v7",
        "22/22"
    ]
}