From 967dc9b1194a9281124b2e1ce67b6c3359a2138f Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Thu, 21 Sep 2017 18:51:04 +1000 Subject: [PATCH] memory: Share FlatView's and dispatch trees between address spaces 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 Message-Id: <20170921085110.25598-13-aik@ozlabs.ru> Signed-off-by: Paolo Bonzini --- memory.c | 56 +++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 45 insertions(+), 11 deletions(-) diff --git a/memory.c b/memory.c index bb582d052a..8ee3c81862 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; /* @@ -761,6 +763,7 @@ static FlatView *generate_memory_topology(MemoryRegion *mr) flatview_add_to_dispatch(view, &mrs); } address_space_dispatch_compact(view->dispatch); + g_hash_table_replace(flat_views, mr, view); return view; } @@ -930,11 +933,47 @@ 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); + + if (g_hash_table_lookup(flat_views, physmr)) { + continue; + } + + generate_memory_topology(physmr); + } +} + +static void address_space_set_flatview(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); @@ -970,10 +1009,12 @@ 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); + address_space_set_flatview(as); address_space_update_ioeventfds(as); } memory_region_update_pending = false; @@ -2696,13 +2737,6 @@ 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; -- GitLab