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GET /api/patches/807508/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 807508,
    "url": "http://patchwork.ozlabs.org/api/patches/807508/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/1504081950-2528-7-git-send-email-peterx@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": "<1504081950-2528-7-git-send-email-peterx@redhat.com>",
    "list_archive_url": null,
    "date": "2017-08-30T08:32:03",
    "name": "[RFC,v2,06/33] migration: reuse mis->userfault_quit_fd",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "dd1f431a41952c1561fa0876bed6495c3d0633ed",
    "submitter": {
        "id": 67717,
        "url": "http://patchwork.ozlabs.org/api/people/67717/?format=api",
        "name": "Peter Xu",
        "email": "peterx@redhat.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/1504081950-2528-7-git-send-email-peterx@redhat.com/mbox/",
    "series": [
        {
            "id": 552,
            "url": "http://patchwork.ozlabs.org/api/series/552/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=552",
            "date": "2017-08-30T08:31:59",
            "name": "Migration: postcopy failure recovery",
            "version": 2,
            "mbox": "http://patchwork.ozlabs.org/series/552/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/807508/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/807508/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": [
            "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)",
            "ext-mx04.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com",
            "ext-mx04.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=peterx@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 3xhzhH28kTz9t2Q\n\tfor <incoming@patchwork.ozlabs.org>;\n\tWed, 30 Aug 2017 18:49:19 +1000 (AEST)",
            "from localhost ([::1]:49083 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 1dmygX-0003rp-0c\n\tfor incoming@patchwork.ozlabs.org; Wed, 30 Aug 2017 04:49:17 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:34023)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <peterx@redhat.com>) id 1dmyQu-00070f-Ub\n\tfor qemu-devel@nongnu.org; Wed, 30 Aug 2017 04:33:10 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <peterx@redhat.com>) id 1dmyQr-0003EV-Ut\n\tfor qemu-devel@nongnu.org; Wed, 30 Aug 2017 04:33:08 -0400",
            "from mx1.redhat.com ([209.132.183.28]:37504)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <peterx@redhat.com>) id 1dmyQr-0003E5-L8\n\tfor qemu-devel@nongnu.org; Wed, 30 Aug 2017 04:33:05 -0400",
            "from smtp.corp.redhat.com\n\t(int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15])\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 A17F58047F;\n\tWed, 30 Aug 2017 08:33:04 +0000 (UTC)",
            "from pxdev.xzpeter.org.com (dhcp-14-103.nay.redhat.com\n\t[10.66.14.103])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id C717B871E6;\n\tWed, 30 Aug 2017 08:33:01 +0000 (UTC)"
        ],
        "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com A17F58047F",
        "From": "Peter Xu <peterx@redhat.com>",
        "To": "qemu-devel@nongnu.org",
        "Date": "Wed, 30 Aug 2017 16:32:03 +0800",
        "Message-Id": "<1504081950-2528-7-git-send-email-peterx@redhat.com>",
        "In-Reply-To": "<1504081950-2528-1-git-send-email-peterx@redhat.com>",
        "References": "<1504081950-2528-1-git-send-email-peterx@redhat.com>",
        "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.15",
        "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.28]);\n\tWed, 30 Aug 2017 08:33:04 +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] [RFC v2 06/33] migration: reuse mis->userfault_quit_fd",
        "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": "Laurent Vivier <lvivier@redhat.com>,\n\tAndrea Arcangeli <aarcange@redhat.com>, \n\tJuan Quintela <quintela@redhat.com>,\n\tAlexey Perevalov <a.perevalov@samsung.com>, peterx@redhat.com,\n\t\"Dr . David Alan Gilbert\" <dgilbert@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": "It was only used for quitting the page fault thread before. Let it be\nsomething more useful - now we can use it to notify a \"wake\" for the\npage fault thread (for any reason), and it only means \"quit\" if the\nfault_thread_quit is set.\n\nSince we changed what it does, renaming it to userfault_event_fd.\n\nReviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>\nSigned-off-by: Peter Xu <peterx@redhat.com>\n---\n migration/migration.h    |  6 ++++--\n migration/postcopy-ram.c | 26 +++++++++++++++++---------\n 2 files changed, 21 insertions(+), 11 deletions(-)",
    "diff": "diff --git a/migration/migration.h b/migration/migration.h\nindex 148c9fa..70e3094 100644\n--- a/migration/migration.h\n+++ b/migration/migration.h\n@@ -35,6 +35,8 @@ struct MigrationIncomingState {\n     bool           have_fault_thread;\n     QemuThread     fault_thread;\n     QemuSemaphore  fault_thread_sem;\n+    /* Set this when we want the fault thread to quit */\n+    bool           fault_thread_quit;\n \n     bool           have_listen_thread;\n     QemuThread     listen_thread;\n@@ -42,8 +44,8 @@ struct MigrationIncomingState {\n \n     /* For the kernel to send us notifications */\n     int       userfault_fd;\n-    /* To tell the fault_thread to quit */\n-    int       userfault_quit_fd;\n+    /* To notify the fault_thread to wake, e.g., when need to quit */\n+    int       userfault_event_fd;\n     QEMUFile *to_src_file;\n     QemuMutex rp_mutex;    /* We send replies from multiple threads */\n     void     *postcopy_tmp_page;\ndiff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c\nindex 7a414eb..0138a49 100644\n--- a/migration/postcopy-ram.c\n+++ b/migration/postcopy-ram.c\n@@ -305,17 +305,18 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)\n          * currently be at 0, we're going to increment it to 1\n          */\n         tmp64 = 1;\n-        if (write(mis->userfault_quit_fd, &tmp64, 8) == 8) {\n+        atomic_set(&mis->fault_thread_quit, 1);\n+        if (write(mis->userfault_event_fd, &tmp64, 8) == 8) {\n             trace_postcopy_ram_incoming_cleanup_join();\n             qemu_thread_join(&mis->fault_thread);\n         } else {\n             /* Not much we can do here, but may as well report it */\n-            error_report(\"%s: incrementing userfault_quit_fd: %s\", __func__,\n+            error_report(\"%s: incrementing userfault_event_fd: %s\", __func__,\n                          strerror(errno));\n         }\n         trace_postcopy_ram_incoming_cleanup_closeuf();\n         close(mis->userfault_fd);\n-        close(mis->userfault_quit_fd);\n+        close(mis->userfault_event_fd);\n         mis->have_fault_thread = false;\n     }\n \n@@ -438,7 +439,7 @@ static void *postcopy_ram_fault_thread(void *opaque)\n         pfd[0].fd = mis->userfault_fd;\n         pfd[0].events = POLLIN;\n         pfd[0].revents = 0;\n-        pfd[1].fd = mis->userfault_quit_fd;\n+        pfd[1].fd = mis->userfault_event_fd;\n         pfd[1].events = POLLIN; /* Waiting for eventfd to go positive */\n         pfd[1].revents = 0;\n \n@@ -448,8 +449,15 @@ static void *postcopy_ram_fault_thread(void *opaque)\n         }\n \n         if (pfd[1].revents) {\n-            trace_postcopy_ram_fault_thread_quit();\n-            break;\n+            uint64_t tmp64 = 0;\n+\n+            /* Consume the signal */\n+            read(mis->userfault_event_fd, &tmp64, 8);\n+\n+            if (atomic_read(&mis->fault_thread_quit)) {\n+                trace_postcopy_ram_fault_thread_quit();\n+                break;\n+            }\n         }\n \n         ret = read(mis->userfault_fd, &msg, sizeof(msg));\n@@ -528,9 +536,9 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)\n     }\n \n     /* Now an eventfd we use to tell the fault-thread to quit */\n-    mis->userfault_quit_fd = eventfd(0, EFD_CLOEXEC);\n-    if (mis->userfault_quit_fd == -1) {\n-        error_report(\"%s: Opening userfault_quit_fd: %s\", __func__,\n+    mis->userfault_event_fd = eventfd(0, EFD_CLOEXEC);\n+    if (mis->userfault_event_fd == -1) {\n+        error_report(\"%s: Opening userfault_event_fd: %s\", __func__,\n                      strerror(errno));\n         close(mis->userfault_fd);\n         return -1;\n",
    "prefixes": [
        "RFC",
        "v2",
        "06/33"
    ]
}