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GET /api/patches/813055/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
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{
    "id": 813055,
    "url": "http://patchwork.ozlabs.org/api/patches/813055/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170912203119.24166-8-eblake@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": "<20170912203119.24166-8-eblake@redhat.com>",
    "list_archive_url": null,
    "date": "2017-09-12T20:31:06",
    "name": "[v7,07/20] dirty-bitmap: Track bitmap size by bytes",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "333ae6ec282c88be55541ef5d2f8b4d693a8464d",
    "submitter": {
        "id": 6591,
        "url": "http://patchwork.ozlabs.org/api/people/6591/?format=api",
        "name": "Eric Blake",
        "email": "eblake@redhat.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170912203119.24166-8-eblake@redhat.com/mbox/",
    "series": [
        {
            "id": 2770,
            "url": "http://patchwork.ozlabs.org/api/series/2770/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=2770",
            "date": "2017-09-12T20:31:00",
            "name": "make dirty-bitmap byte-based",
            "version": 7,
            "mbox": "http://patchwork.ozlabs.org/series/2770/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/813055/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/813055/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-mx08.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=eblake@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 3xsGpX3ybjz9sNw\n\tfor <incoming@patchwork.ozlabs.org>;\n\tWed, 13 Sep 2017 06:38:28 +1000 (AEST)",
            "from localhost ([::1]:38471 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 1drrww-0000HM-JV\n\tfor incoming@patchwork.ozlabs.org; Tue, 12 Sep 2017 16:38:26 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:39412)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1drrqU-0001iv-4S\n\tfor qemu-devel@nongnu.org; Tue, 12 Sep 2017 16:31:47 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1drrqR-0005jA-Em\n\tfor qemu-devel@nongnu.org; Tue, 12 Sep 2017 16:31:46 -0400",
            "from mx1.redhat.com ([209.132.183.28]:35743)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <eblake@redhat.com>)\n\tid 1drrqN-0005Yj-VH; Tue, 12 Sep 2017 16:31:40 -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 00A39C057FAF;\n\tTue, 12 Sep 2017 20:31:39 +0000 (UTC)",
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        ],
        "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com 00A39C057FAF",
        "From": "Eric Blake <eblake@redhat.com>",
        "To": "qemu-devel@nongnu.org",
        "Date": "Tue, 12 Sep 2017 15:31:06 -0500",
        "Message-Id": "<20170912203119.24166-8-eblake@redhat.com>",
        "In-Reply-To": "<20170912203119.24166-1-eblake@redhat.com>",
        "References": "<20170912203119.24166-1-eblake@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 [10.5.110.32]);\n\tTue, 12 Sep 2017 20:31:39 +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 07/20] dirty-bitmap: Track bitmap size by\n\tbytes",
        "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": "kwolf@redhat.com, vsementsov@virtuozzo.com, Fam Zheng <famz@redhat.com>, \n\tqemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>, jsnow@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": "We are still using an internal hbitmap that tracks a size in sectors,\nwith the granularity scaled down accordingly, because it lets us\nuse a shortcut for our iterators which are currently sector-based.\nBut there's no reason we can't track the dirty bitmap size in bytes,\nsince it is (mostly) an internal-only variable (remember, the size\nis how many bytes are covered by the bitmap, not how many bytes the\nbitmap occupies).  A later cleanup will convert dirty bitmap\ninternals to be entirely byte-based, eliminating the intermediate\nsector rounding added here; and technically, since bdrv_getlength()\nalready rounds up to sectors, our use of DIV_ROUND_UP is more for\ntheoretical completeness than for any actual rounding.\n\nUse is_power_of_2() while at it, instead of open-coding that.\n\nSigned-off-by: Eric Blake <eblake@redhat.com>\n\n---\nv7: split external from internal [Kevin], drop R-b\nv6: no change\nv5: fix bdrv_dirty_bitmap_truncate [John], drop R-b\nv4: retitle from \"Track size in bytes\", rebase to persistent bitmaps,\nround up when converting bytes to sectors\nv3: no change\nv2: tweak commit message, no code change\n---\n block/dirty-bitmap.c | 25 ++++++++++++++-----------\n 1 file changed, 14 insertions(+), 11 deletions(-)",
    "diff": "diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c\nindex 56a01699e9..ec4fc0e1ad 100644\n--- a/block/dirty-bitmap.c\n+++ b/block/dirty-bitmap.c\n@@ -42,7 +42,7 @@ struct BdrvDirtyBitmap {\n     HBitmap *meta;              /* Meta dirty bitmap */\n     BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */\n     char *name;                 /* Optional non-empty unique ID */\n-    int64_t size;               /* Size of the bitmap (Number of sectors) */\n+    int64_t size;               /* Size of the bitmap, in bytes */\n     bool disabled;              /* Bitmap is disabled. It ignores all writes to\n                                    the device */\n     int active_iterators;       /* How many iterators are active */\n@@ -115,17 +115,14 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,\n {\n     int64_t bitmap_size;\n     BdrvDirtyBitmap *bitmap;\n-    uint32_t sector_granularity;\n\n-    assert((granularity & (granularity - 1)) == 0);\n+    assert(is_power_of_2(granularity) && granularity >= BDRV_SECTOR_SIZE);\n\n     if (name && bdrv_find_dirty_bitmap(bs, name)) {\n         error_setg(errp, \"Bitmap already exists: %s\", name);\n         return NULL;\n     }\n-    sector_granularity = granularity >> BDRV_SECTOR_BITS;\n-    assert(sector_granularity);\n-    bitmap_size = bdrv_nb_sectors(bs);\n+    bitmap_size = bdrv_getlength(bs);\n     if (bitmap_size < 0) {\n         error_setg_errno(errp, -bitmap_size, \"could not get length of device\");\n         errno = -bitmap_size;\n@@ -133,7 +130,12 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,\n     }\n     bitmap = g_new0(BdrvDirtyBitmap, 1);\n     bitmap->mutex = &bs->dirty_bitmap_mutex;\n-    bitmap->bitmap = hbitmap_alloc(bitmap_size, ctz32(sector_granularity));\n+    /*\n+     * TODO - let hbitmap track full granularity. For now, it is tracking\n+     * only sector granularity, as a shortcut for our iterators.\n+     */\n+    bitmap->bitmap = hbitmap_alloc(DIV_ROUND_UP(bitmap_size, BDRV_SECTOR_SIZE),\n+                                   ctz32(granularity) - BDRV_SECTOR_BITS);\n     bitmap->size = bitmap_size;\n     bitmap->name = g_strdup(name);\n     bitmap->disabled = false;\n@@ -175,7 +177,7 @@ void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)\n\n int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap)\n {\n-    return bitmap->size * BDRV_SECTOR_SIZE;\n+    return bitmap->size;\n }\n\n const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)\n@@ -305,7 +307,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,\n int bdrv_dirty_bitmap_truncate(BlockDriverState *bs)\n {\n     BdrvDirtyBitmap *bitmap;\n-    int64_t size = bdrv_nb_sectors(bs);\n+    int64_t size = bdrv_getlength(bs);\n\n     if (size < 0) {\n         return size;\n@@ -314,7 +316,7 @@ int bdrv_dirty_bitmap_truncate(BlockDriverState *bs)\n     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {\n         assert(!bdrv_dirty_bitmap_frozen(bitmap));\n         assert(!bitmap->active_iterators);\n-        hbitmap_truncate(bitmap->bitmap, size);\n+        hbitmap_truncate(bitmap->bitmap, DIV_ROUND_UP(size, BDRV_SECTOR_SIZE));\n         bitmap->size = size;\n     }\n     bdrv_dirty_bitmaps_unlock(bs);\n@@ -553,7 +555,8 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)\n         hbitmap_reset_all(bitmap->bitmap);\n     } else {\n         HBitmap *backup = bitmap->bitmap;\n-        bitmap->bitmap = hbitmap_alloc(bitmap->size,\n+        bitmap->bitmap = hbitmap_alloc(DIV_ROUND_UP(bitmap->size,\n+                                                    BDRV_SECTOR_SIZE),\n                                        hbitmap_granularity(backup));\n         *out = backup;\n     }\n",
    "prefixes": [
        "v7",
        "07/20"
    ]
}