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GET /api/patches/816312/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 816312,
    "url": "http://patchwork.ozlabs.org/api/patches/816312/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170920114637.42004-13-aik@ozlabs.ru/",
    "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": "<20170920114637.42004-13-aik@ozlabs.ru>",
    "list_archive_url": null,
    "date": "2017-09-20T11:46:31",
    "name": "[qemu,v4,12/18] memory: Share FlatView's and dispatch trees between address spaces",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "72c6ef5011fa86ece5d400b83e057080e4dfe098",
    "submitter": {
        "id": 7621,
        "url": "http://patchwork.ozlabs.org/api/people/7621/?format=api",
        "name": "Alexey Kardashevskiy",
        "email": "aik@ozlabs.ru"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170920114637.42004-13-aik@ozlabs.ru/mbox/",
    "series": [
        {
            "id": 4138,
            "url": "http://patchwork.ozlabs.org/api/series/4138/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4138",
            "date": "2017-09-20T11:46:20",
            "name": "memory: Reduce memory use",
            "version": 4,
            "mbox": "http://patchwork.ozlabs.org/series/4138/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/816312/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/816312/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>)",
        "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 3xy3f14T1jz9sPt\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 21 Sep 2017 01:32:40 +1000 (AEST)",
            "from localhost ([::1]:48895 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 1dugzO-000117-6L\n\tfor incoming@patchwork.ozlabs.org; Wed, 20 Sep 2017 11:32:38 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:56356)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <aik@ozlabs.ru>) id 1dufmG-0003O4-Mb\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:15:02 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <aik@ozlabs.ru>) id 1dufmD-00057G-6X\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:15:00 -0400",
            "from ozlabs.ru ([107.173.13.209]:59738)\n\tby eggs.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <aik@ozlabs.ru>) id 1dufmC-00056v-Ue\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:14:57 -0400",
            "from vpl1.ozlabs.ibm.com (localhost [IPv6:::1])\n\tby ozlabs.ru (Postfix) with ESMTP id 35BB03A6005B;\n\tWed, 20 Sep 2017 07:48:11 -0400 (EDT)"
        ],
        "From": "Alexey Kardashevskiy <aik@ozlabs.ru>",
        "To": "qemu-devel@nongnu.org",
        "Date": "Wed, 20 Sep 2017 21:46:31 +1000",
        "Message-Id": "<20170920114637.42004-13-aik@ozlabs.ru>",
        "X-Mailer": "git-send-email 2.11.0",
        "In-Reply-To": "<20170920114637.42004-1-aik@ozlabs.ru>",
        "References": "<20170920114637.42004-1-aik@ozlabs.ru>",
        "X-detected-operating-system": "by eggs.gnu.org: GNU/Linux 3.x [fuzzy]",
        "X-Received-From": "107.173.13.209",
        "Subject": "[Qemu-devel] [PATCH qemu v4 12/18] memory: Share FlatView's and\n\tdispatch trees between address spaces",
        "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": "Alexey Kardashevskiy <aik@ozlabs.ru>, Paolo Bonzini <pbonzini@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": "This allows sharing flat views between address spaces (AS) when\nthe same root memory region is used when creating a new address space.\nThis is done by walking through all ASes and caching one FlatView per\na physical root MR (i.e. not aliased).\n\nThis removes search for duplicates from address_space_init_shareable() as\nFlatViews are shared elsewhere and keeping as::ref_count correct seems\nan unnecessary and useless complication.\n\nThis should cause no change and memory use or boot time yet.\n\nSigned-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>\n---\nChanges:\nv4:\n* used g_hash_table_new_full() instead of g_hash_table_new() +\ng_hash_table_foreach_remove()\n* cached last hash table of FV globally\n\nv3:\n* got rid of global and per-AS lists of FlatView objects\n---\n memory.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++-----------\n 1 file changed, 46 insertions(+), 11 deletions(-)",
    "diff": "diff --git a/memory.c b/memory.c\nindex 9868d0f57c..1083fe9130 100644\n--- a/memory.c\n+++ b/memory.c\n@@ -47,6 +47,8 @@ static QTAILQ_HEAD(memory_listeners, MemoryListener) memory_listeners\n static QTAILQ_HEAD(, AddressSpace) address_spaces\n     = QTAILQ_HEAD_INITIALIZER(address_spaces);\n \n+static GHashTable *flat_views;\n+\n typedef struct AddrRange AddrRange;\n \n /*\n@@ -925,11 +927,49 @@ static void address_space_update_topology_pass(AddressSpace *as,\n     }\n }\n \n-static void address_space_update_topology(AddressSpace *as)\n+static void flatviews_init(void)\n+{\n+    if (flat_views) {\n+        return;\n+    }\n+\n+    flat_views = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,\n+                                       (GDestroyNotify) flatview_unref);\n+}\n+\n+static void flatviews_reset(void)\n+{\n+    AddressSpace *as;\n+\n+    if (flat_views) {\n+        g_hash_table_unref(flat_views);\n+        flat_views = NULL;\n+    }\n+    flatviews_init();\n+\n+    /* Render unique FVs */\n+    QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {\n+        MemoryRegion *physmr = memory_region_get_flatview_root(as->root);\n+        FlatView *new_view = g_hash_table_lookup(flat_views, physmr);\n+\n+        if (new_view) {\n+            continue;\n+        }\n+\n+        new_view = generate_memory_topology(physmr);\n+        g_hash_table_insert(flat_views, physmr, new_view);\n+    }\n+}\n+\n+static void flatview_set_to_address_space(AddressSpace *as)\n {\n     FlatView *old_view = address_space_get_flatview(as);\n-    MemoryRegion *physmr = memory_region_get_flatview_root(old_view->root);\n-    FlatView *new_view = generate_memory_topology(physmr);\n+    MemoryRegion *physmr = memory_region_get_flatview_root(as->root);\n+    FlatView *new_view = g_hash_table_lookup(flat_views, physmr);\n+\n+    assert(new_view);\n+\n+    flatview_ref(new_view);\n \n     if (!QTAILQ_EMPTY(&as->listeners)) {\n         address_space_update_topology_pass(as, old_view, new_view, false);\n@@ -965,10 +1005,12 @@ void memory_region_transaction_commit(void)\n     --memory_region_transaction_depth;\n     if (!memory_region_transaction_depth) {\n         if (memory_region_update_pending) {\n+            flatviews_reset();\n+\n             MEMORY_LISTENER_CALL_GLOBAL(begin, Forward);\n \n             QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {\n-                address_space_update_topology(as);\n+                flatview_set_to_address_space(as);\n                 address_space_update_ioeventfds(as);\n             }\n             memory_region_update_pending = false;\n@@ -2691,13 +2733,6 @@ AddressSpace *address_space_init_shareable(MemoryRegion *root, const char *name)\n {\n     AddressSpace *as;\n \n-    QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {\n-        if (root == as->root && as->malloced) {\n-            as->ref_count++;\n-            return as;\n-        }\n-    }\n-\n     as = g_malloc0(sizeof *as);\n     address_space_init(as, root, name);\n     as->malloced = true;\n",
    "prefixes": [
        "qemu",
        "v4",
        "12/18"
    ]
}