From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56356) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dufmG-0003O4-Mb for qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:15:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dufmD-00057G-6X for qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:15:00 -0400 Received: from ozlabs.ru ([107.173.13.209]:59738) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dufmC-00056v-Ue for qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:14:57 -0400 From: Alexey Kardashevskiy Date: Wed, 20 Sep 2017 21:46:31 +1000 Message-Id: <20170920114637.42004-13-aik@ozlabs.ru> In-Reply-To: <20170920114637.42004-1-aik@ozlabs.ru> References: <20170920114637.42004-1-aik@ozlabs.ru> Subject: [Qemu-devel] [PATCH qemu v4 12/18] memory: Share FlatView's and dispatch trees between address spaces List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Alexey Kardashevskiy , Paolo Bonzini This allows sharing flat views between address spaces (AS) when the same root memory region is used when creating a new address space. This is done by walking through all ASes and caching one FlatView per a physical root MR (i.e. not aliased). This removes search for duplicates from address_space_init_shareable() as FlatViews are shared elsewhere and keeping as::ref_count correct seems an unnecessary and useless complication. This should cause no change and memory use or boot time yet. Signed-off-by: Alexey Kardashevskiy --- Changes: v4: * used g_hash_table_new_full() instead of g_hash_table_new() + g_hash_table_foreach_remove() * cached last hash table of FV globally v3: * got rid of global and per-AS lists of FlatView objects --- memory.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 46 insertions(+), 11 deletions(-) diff --git a/memory.c b/memory.c index 9868d0f57c..1083fe9130 100644 --- a/memory.c +++ b/memory.c @@ -47,6 +47,8 @@ static QTAILQ_HEAD(memory_listeners, MemoryListener) memory_listeners static QTAILQ_HEAD(, AddressSpace) address_spaces = QTAILQ_HEAD_INITIALIZER(address_spaces); +static GHashTable *flat_views; + typedef struct AddrRange AddrRange; /* @@ -925,11 +927,49 @@ static void address_space_update_topology_pass(AddressSpace *as, } } -static void address_space_update_topology(AddressSpace *as) +static void flatviews_init(void) +{ + if (flat_views) { + return; + } + + flat_views = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, + (GDestroyNotify) flatview_unref); +} + +static void flatviews_reset(void) +{ + AddressSpace *as; + + if (flat_views) { + g_hash_table_unref(flat_views); + flat_views = NULL; + } + flatviews_init(); + + /* Render unique FVs */ + QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) { + MemoryRegion *physmr = memory_region_get_flatview_root(as->root); + FlatView *new_view = g_hash_table_lookup(flat_views, physmr); + + if (new_view) { + continue; + } + + new_view = generate_memory_topology(physmr); + g_hash_table_insert(flat_views, physmr, new_view); + } +} + +static void flatview_set_to_address_space(AddressSpace *as) { FlatView *old_view = address_space_get_flatview(as); - MemoryRegion *physmr = memory_region_get_flatview_root(old_view->root); - FlatView *new_view = generate_memory_topology(physmr); + MemoryRegion *physmr = memory_region_get_flatview_root(as->root); + FlatView *new_view = g_hash_table_lookup(flat_views, physmr); + + assert(new_view); + + flatview_ref(new_view); if (!QTAILQ_EMPTY(&as->listeners)) { address_space_update_topology_pass(as, old_view, new_view, false); @@ -965,10 +1005,12 @@ void memory_region_transaction_commit(void) --memory_region_transaction_depth; if (!memory_region_transaction_depth) { if (memory_region_update_pending) { + flatviews_reset(); + MEMORY_LISTENER_CALL_GLOBAL(begin, Forward); QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) { - address_space_update_topology(as); + flatview_set_to_address_space(as); address_space_update_ioeventfds(as); } memory_region_update_pending = false; @@ -2691,13 +2733,6 @@ AddressSpace *address_space_init_shareable(MemoryRegion *root, const char *name) { AddressSpace *as; - QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) { - if (root == as->root && as->malloced) { - as->ref_count++; - return as; - } - } - as = g_malloc0(sizeof *as); address_space_init(as, root, name); as->malloced = true; -- 2.11.0