From 25254bbc4d91408b6be706d095e3fbc60a972db4 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 6 Apr 2011 22:09:54 +0300 Subject: [PATCH] kvm: halve number of set memory calls for vga use the new api to reduce the number of these (expensive) system calls. Note: using this API, we should be able to get rid of vga_dirty_log_xxx APIs. Using them doesn't affect the performance though because we detects the log_dirty flag set and ignores the call. Signed-off-by: Michael S. Tsirkin --- kvm-all.c | 59 +++++++++++++++++++++++++++++++++---------------------- 1 file changed, 36 insertions(+), 23 deletions(-) diff --git a/kvm-all.c b/kvm-all.c index 1647e1a273..7ace9a2d7c 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -245,48 +245,60 @@ err: /* * dirty pages logging control */ -static int kvm_dirty_pages_log_change(target_phys_addr_t phys_addr, - ram_addr_t size, int flags, int mask) + +static int kvm_mem_flags(KVMState *s, bool log_dirty) +{ + return log_dirty ? KVM_MEM_LOG_DIRTY_PAGES : 0; +} + +static int kvm_slot_dirty_pages_log_change(KVMSlot *mem, bool log_dirty) { KVMState *s = kvm_state; - KVMSlot *mem = kvm_lookup_matching_slot(s, phys_addr, phys_addr + size); + int flags, mask = KVM_MEM_LOG_DIRTY_PAGES; int old_flags; - if (mem == NULL) { - fprintf(stderr, "BUG: %s: invalid parameters " TARGET_FMT_plx "-" - TARGET_FMT_plx "\n", __func__, phys_addr, - (target_phys_addr_t)(phys_addr + size - 1)); - return -EINVAL; - } - old_flags = mem->flags; - flags = (mem->flags & ~mask) | flags; + flags = (mem->flags & ~mask) | kvm_mem_flags(s, log_dirty); mem->flags = flags; /* If nothing changed effectively, no need to issue ioctl */ if (s->migration_log) { flags |= KVM_MEM_LOG_DIRTY_PAGES; } + if (flags == old_flags) { - return 0; + return 0; } return kvm_set_user_memory_region(s, mem); } +static int kvm_dirty_pages_log_change(target_phys_addr_t phys_addr, + ram_addr_t size, bool log_dirty) +{ + KVMState *s = kvm_state; + KVMSlot *mem = kvm_lookup_matching_slot(s, phys_addr, phys_addr + size); + + if (mem == NULL) { + fprintf(stderr, "BUG: %s: invalid parameters " TARGET_FMT_plx "-" + TARGET_FMT_plx "\n", __func__, phys_addr, + (target_phys_addr_t)(phys_addr + size - 1)); + return -EINVAL; + } + return kvm_slot_dirty_pages_log_change(mem, log_dirty); +} + static int kvm_log_start(CPUPhysMemoryClient *client, target_phys_addr_t phys_addr, ram_addr_t size) { - return kvm_dirty_pages_log_change(phys_addr, size, KVM_MEM_LOG_DIRTY_PAGES, - KVM_MEM_LOG_DIRTY_PAGES); + return kvm_dirty_pages_log_change(phys_addr, size, true); } static int kvm_log_stop(CPUPhysMemoryClient *client, target_phys_addr_t phys_addr, ram_addr_t size) { - return kvm_dirty_pages_log_change(phys_addr, size, 0, - KVM_MEM_LOG_DIRTY_PAGES); + return kvm_dirty_pages_log_change(phys_addr, size, false); } static int kvm_set_migration_log(int enable) @@ -495,7 +507,7 @@ kvm_check_extension_list(KVMState *s, const KVMCapabilityInfo *list) } static void kvm_set_phys_mem(target_phys_addr_t start_addr, ram_addr_t size, - ram_addr_t phys_offset) + ram_addr_t phys_offset, bool log_dirty) { KVMState *s = kvm_state; ram_addr_t flags = phys_offset & ~TARGET_PAGE_MASK; @@ -520,7 +532,8 @@ static void kvm_set_phys_mem(target_phys_addr_t start_addr, ram_addr_t size, (start_addr + size <= mem->start_addr + mem->memory_size) && (phys_offset - start_addr == mem->phys_offset - mem->start_addr)) { /* The new slot fits into the existing one and comes with - * identical parameters - nothing to be done. */ + * identical parameters - update flags and done. */ + kvm_slot_dirty_pages_log_change(mem, log_dirty); return; } @@ -550,7 +563,7 @@ static void kvm_set_phys_mem(target_phys_addr_t start_addr, ram_addr_t size, mem->memory_size = old.memory_size; mem->start_addr = old.start_addr; mem->phys_offset = old.phys_offset; - mem->flags = 0; + mem->flags = kvm_mem_flags(s, log_dirty); err = kvm_set_user_memory_region(s, mem); if (err) { @@ -571,7 +584,7 @@ static void kvm_set_phys_mem(target_phys_addr_t start_addr, ram_addr_t size, mem->memory_size = start_addr - old.start_addr; mem->start_addr = old.start_addr; mem->phys_offset = old.phys_offset; - mem->flags = 0; + mem->flags = kvm_mem_flags(s, log_dirty); err = kvm_set_user_memory_region(s, mem); if (err) { @@ -590,7 +603,7 @@ static void kvm_set_phys_mem(target_phys_addr_t start_addr, ram_addr_t size, size_delta = mem->start_addr - old.start_addr; mem->memory_size = old.memory_size - size_delta; mem->phys_offset = old.phys_offset + size_delta; - mem->flags = 0; + mem->flags = kvm_mem_flags(s, log_dirty); err = kvm_set_user_memory_region(s, mem); if (err) { @@ -613,7 +626,7 @@ static void kvm_set_phys_mem(target_phys_addr_t start_addr, ram_addr_t size, mem->memory_size = size; mem->start_addr = start_addr; mem->phys_offset = phys_offset; - mem->flags = 0; + mem->flags = kvm_mem_flags(s, log_dirty); err = kvm_set_user_memory_region(s, mem); if (err) { @@ -628,7 +641,7 @@ static void kvm_client_set_memory(struct CPUPhysMemoryClient *client, ram_addr_t size, ram_addr_t phys_offset, bool log_dirty) { - kvm_set_phys_mem(start_addr, size, phys_offset); + kvm_set_phys_mem(start_addr, size, phys_offset, log_dirty); } static int kvm_client_sync_dirty_bitmap(struct CPUPhysMemoryClient *client,