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[Qemu-devel] [PATCH RFC 2/5] kvm: halve number of set memory calls for v
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PATCH RFC 2/5] kvm: halve number of set memory calls for vga |
Date: |
Wed, 6 Apr 2011 23:41:47 +0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
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 <address@hidden>
---
kvm-all.c | 59 ++++++++++++++++++++++++++++++++++++-----------------------
1 files changed, 36 insertions(+), 23 deletions(-)
diff --git a/kvm-all.c b/kvm-all.c
index 1647e1a..7ace9a2 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,
--
1.7.3.2.91.g446ac
- [Qemu-devel] [PATCH RFC 0/5] kvm/vhost: enable durty logging during memory registration, Michael S. Tsirkin, 2011/04/06
- [Qemu-devel] [PATCH RFC 1/5] cpu: add set_memory flag to request dirty logging, Michael S. Tsirkin, 2011/04/06
- [Qemu-devel] [PATCH RFC 5/5] cirrus_vga: flag on-device ram for dirty logging, Michael S. Tsirkin, 2011/04/06
- [Qemu-devel] [PATCH RFC 4/5] vhost: optimize out no-change assignment, Michael S. Tsirkin, 2011/04/06
- [Qemu-devel] [PATCH RFC 2/5] kvm: halve number of set memory calls for vga,
Michael S. Tsirkin <=
- [Qemu-devel] [PATCH RFC 3/5] vhost: skip memory which needs dirty logging, Michael S. Tsirkin, 2011/04/06
- Re: [Qemu-devel] [PATCH RFC 0/5] kvm/vhost: enable durty logging during memory registration, Brad Hards, 2011/04/07