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[Qemu-devel] [PULL 15/19] kvm: Persistent per kvmslot dirty bitmap
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PULL 15/19] kvm: Persistent per kvmslot dirty bitmap |
Date: |
Fri, 12 Jul 2019 16:32:03 +0200 |
From: Peter Xu <address@hidden>
When synchronizing dirty bitmap from kernel KVM we do it in a
per-kvmslot fashion and we allocate the userspace bitmap for each of
the ioctl. This patch instead make the bitmap cache be persistent
then we don't need to g_malloc0() every time.
More importantly, the cached per-kvmslot dirty bitmap will be further
used when we want to add support for the KVM_CLEAR_DIRTY_LOG and this
cached bitmap will be used to guarantee we won't clear any unknown
dirty bits otherwise that can be a severe data loss issue for
migration code.
Signed-off-by: Peter Xu <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
---
accel/kvm/kvm-all.c | 10 +++++++---
include/sysemu/kvm_int.h | 2 ++
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index a3df19da56..23ace52b9e 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -516,17 +516,19 @@ static int
kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml,
*/
size = ALIGN(((mem->memory_size) >> TARGET_PAGE_BITS),
/*HOST_LONG_BITS*/ 64) / 8;
- d.dirty_bitmap = g_malloc0(size);
+ if (!mem->dirty_bmap) {
+ /* Allocate on the first log_sync, once and for all */
+ mem->dirty_bmap = g_malloc0(size);
+ }
+ d.dirty_bitmap = mem->dirty_bmap;
d.slot = mem->slot | (kml->as_id << 16);
if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) {
DPRINTF("ioctl failed %d\n", errno);
- g_free(d.dirty_bitmap);
return -1;
}
kvm_get_dirty_pages_log_range(section, d.dirty_bitmap);
- g_free(d.dirty_bitmap);
}
return 0;
@@ -801,6 +803,8 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
}
/* unregister the slot */
+ g_free(mem->dirty_bmap);
+ mem->dirty_bmap = NULL;
mem->memory_size = 0;
mem->flags = 0;
err = kvm_set_user_memory_region(kml, mem, false);
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index f838412491..687a2ee423 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -21,6 +21,8 @@ typedef struct KVMSlot
int slot;
int flags;
int old_flags;
+ /* Dirty bitmap cache for the slot */
+ unsigned long *dirty_bmap;
} KVMSlot;
typedef struct KVMMemoryListener {
--
2.21.0
- [Qemu-devel] [PULL 06/19] cutils: remove one unnecessary pointer operation, (continued)
- [Qemu-devel] [PULL 06/19] cutils: remove one unnecessary pointer operation, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 04/19] migration/multifd: call multifd_send_sync_main when sending RAM_SAVE_FLAG_EOS, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 07/19] migration/multifd: sync packet_num after all thread are done, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 09/19] migration: No need to take rcu during sync_dirty_bitmap, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 08/19] migration/ram.c: reset complete_round when we gets a queued page, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 10/19] memory: Don't set migration bitmap when without migration, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 11/19] bitmap: Add bitmap_copy_with_{src|dst}_offset(), Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 12/19] memory: Pass mr into snapshot_and_clear_dirty, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 13/19] memory: Introduce memory listener hook log_clear(), Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 14/19] kvm: Update comments for sync_dirty_bitmap, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 15/19] kvm: Persistent per kvmslot dirty bitmap,
Juan Quintela <=
- [Qemu-devel] [PULL 16/19] kvm: Introduce slots lock for memory listener, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 17/19] kvm: Support KVM_CLEAR_DIRTY_LOG, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 18/19] migration: Split log_clear() into smaller chunks, Juan Quintela, 2019/07/12
- [Qemu-devel] [PULL 19/19] migration: allow private destination ram with x-ignore-shared, Juan Quintela, 2019/07/12
- Re: [Qemu-devel] [PULL 00/19] Migration patches, Peter Maydell, 2019/07/12
- Re: [Qemu-devel] [PULL 00/19] Migration patches, Dr. David Alan Gilbert, 2019/07/12
- Re: [Qemu-devel] [PULL 00/19] Migration patches, Peter Maydell, 2019/07/15
- Re: [Qemu-devel] [PULL 00/19] Migration patches, Juan Quintela, 2019/07/15
- Re: [Qemu-devel] [PULL 00/19] Migration patches, Peter Maydell, 2019/07/15
- Re: [Qemu-devel] [PULL 00/19] Migration patches, Juan Quintela, 2019/07/15