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GET /api/patches/808131/?format=api
{ "id": 808131, "url": "http://patchwork.ozlabs.org/api/patches/808131/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170831082210.8362-16-stefanha@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": "<20170831082210.8362-16-stefanha@redhat.com>", "list_archive_url": null, "date": "2017-08-31T08:22:10", "name": "[PULL,for-2.10,15/15] qcow2: allocate cluster_cache/cluster_data on demand", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "3bf10fcdfac713cfe3474e4c078dcc2bba0d4c7b", "submitter": { "id": 17227, "url": "http://patchwork.ozlabs.org/api/people/17227/?format=api", "name": "Stefan Hajnoczi", "email": "stefanha@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170831082210.8362-16-stefanha@redhat.com/mbox/", "series": [ { "id": 766, "url": "http://patchwork.ozlabs.org/api/series/766/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=766", "date": "2017-08-31T08:21:55", "name": "[PULL,for-2.10,01/15] nvme: Fix get/set number of queues feature, again", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/766/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/808131/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/808131/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-mx09.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com", "ext-mx09.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=stefanha@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 3xjbCb5lSXz9s7c\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 31 Aug 2017 18:30:03 +1000 (AEST)", "from localhost ([::1]:54497 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 1dnKrR-0002jo-S6\n\tfor incoming@patchwork.ozlabs.org; Thu, 31 Aug 2017 04:30:01 -0400", "from eggs.gnu.org ([2001:4830:134:3::10]:42737)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <stefanha@redhat.com>) id 1dnKkp-0005nP-Kn\n\tfor qemu-devel@nongnu.org; Thu, 31 Aug 2017 04:23:17 -0400", "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <stefanha@redhat.com>) id 1dnKko-00060x-EH\n\tfor qemu-devel@nongnu.org; Thu, 31 Aug 2017 04:23:11 -0400", "from mx1.redhat.com ([209.132.183.28]:54358)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <stefanha@redhat.com>) id 1dnKko-00060r-5q\n\tfor qemu-devel@nongnu.org; Thu, 31 Aug 2017 04:23:10 -0400", "from smtp.corp.redhat.com\n\t(int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14])\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 538B1404314;\n\tThu, 31 Aug 2017 08:23:09 +0000 (UTC)", "from localhost (ovpn-117-89.ams2.redhat.com [10.36.117.89])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id 0BF2E18BBE;\n\tThu, 31 Aug 2017 08:23:06 +0000 (UTC)" ], "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com 538B1404314", "From": "Stefan Hajnoczi <stefanha@redhat.com>", "To": "<qemu-devel@nongnu.org>", "Date": "Thu, 31 Aug 2017 09:22:10 +0100", "Message-Id": "<20170831082210.8362-16-stefanha@redhat.com>", "In-Reply-To": "<20170831082210.8362-1-stefanha@redhat.com>", "References": "<20170831082210.8362-1-stefanha@redhat.com>", "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.14", "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.38]);\n\tThu, 31 Aug 2017 08:23:09 +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] [PULL for-2.10 15/15] qcow2: allocate\n\tcluster_cache/cluster_data on demand", "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": "Kevin Wolf <kwolf@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, \n\tStefan Hajnoczi <stefanha@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": "Most qcow2 files are uncompressed so it is wasteful to allocate (32 + 1)\n* cluster_size + 512 bytes upfront. Allocate s->cluster_cache and\ns->cluster_data when the first read operation is performance on a\ncompressed cluster.\n\nThe buffers are freed in .bdrv_close(). .bdrv_open() no longer has any\ncode paths that can allocate these buffers, so remove the free functions\nin the error code path.\n\nThis patch can result in significant memory savings when many qcow2\ndisks are attached or backing file chains are long:\n\nBefore 12.81% (1,023,193,088B)\nAfter 5.36% (393,893,888B)\n\nReported-by: Alexey Kardashevskiy <aik@ozlabs.ru>\nTested-by: Alexey Kardashevskiy <aik@ozlabs.ru>\nReviewed-by: Eric Blake <eblake@redhat.com>\nSigned-off-by: Stefan Hajnoczi <stefanha@redhat.com>\nMessage-id: 20170821135530.32344-1-stefanha@redhat.com\nCc: Kevin Wolf <kwolf@redhat.com>\nSigned-off-by: Stefan Hajnoczi <stefanha@redhat.com>\n---\n block/qcow2-cluster.c | 17 +++++++++++++++++\n block/qcow2.c | 12 ------------\n 2 files changed, 17 insertions(+), 12 deletions(-)", "diff": "diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c\nindex f06c08f64c..8538533102 100644\n--- a/block/qcow2-cluster.c\n+++ b/block/qcow2-cluster.c\n@@ -1516,6 +1516,23 @@ int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)\n nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;\n sector_offset = coffset & 511;\n csize = nb_csectors * 512 - sector_offset;\n+\n+ /* Allocate buffers on first decompress operation, most images are\n+ * uncompressed and the memory overhead can be avoided. The buffers\n+ * are freed in .bdrv_close().\n+ */\n+ if (!s->cluster_data) {\n+ /* one more sector for decompressed data alignment */\n+ s->cluster_data = qemu_try_blockalign(bs->file->bs,\n+ QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size + 512);\n+ if (!s->cluster_data) {\n+ return -ENOMEM;\n+ }\n+ }\n+ if (!s->cluster_cache) {\n+ s->cluster_cache = g_malloc(s->cluster_size);\n+ }\n+\n BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);\n ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data,\n nb_csectors);\ndiff --git a/block/qcow2.c b/block/qcow2.c\nindex fbfffadc76..a3679c69e8 100644\n--- a/block/qcow2.c\n+++ b/block/qcow2.c\n@@ -1360,16 +1360,6 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,\n goto fail;\n }\n \n- s->cluster_cache = g_malloc(s->cluster_size);\n- /* one more sector for decompressed data alignment */\n- s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS\n- * s->cluster_size + 512);\n- if (s->cluster_data == NULL) {\n- error_setg(errp, \"Could not allocate temporary cluster buffer\");\n- ret = -ENOMEM;\n- goto fail;\n- }\n-\n s->cluster_cache_offset = -1;\n s->flags = flags;\n \n@@ -1507,8 +1497,6 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,\n if (s->refcount_block_cache) {\n qcow2_cache_destroy(bs, s->refcount_block_cache);\n }\n- g_free(s->cluster_cache);\n- qemu_vfree(s->cluster_data);\n qcrypto_block_free(s->crypto);\n qapi_free_QCryptoBlockOpenOptions(s->crypto_opts);\n return ret;\n", "prefixes": [ "PULL", "for-2.10", "15/15" ] }