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[Qemu-devel] [PATCH 01/11] migration: No need to take rcu during sync_di
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH 01/11] migration: No need to take rcu during sync_dirty_bitmap |
Date: |
Wed, 8 May 2019 14:15:13 +0800 |
cpu_physical_memory_sync_dirty_bitmap() has one RAMBlock* as
parameter, which means that it must be with RCU read lock held
already. Taking it again inside seems redundant. Removing it.
Instead comment on the functions about the RCU read lock.
Signed-off-by: Peter Xu <address@hidden>
---
include/exec/ram_addr.h | 5 +----
migration/ram.c | 1 +
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 139ad79390..993fb760f3 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -408,6 +408,7 @@ static inline void
cpu_physical_memory_clear_dirty_range(ram_addr_t start,
}
+/* Must be with rcu read lock held */
static inline
uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb,
ram_addr_t start,
@@ -431,8 +432,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb,
DIRTY_MEMORY_BLOCK_SIZE);
unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
- rcu_read_lock();
-
src = atomic_rcu_read(
&ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION])->blocks;
@@ -452,8 +451,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb,
idx++;
}
}
-
- rcu_read_unlock();
} else {
ram_addr_t offset = rb->offset;
diff --git a/migration/ram.c b/migration/ram.c
index 1ca9ba77b6..3e11806ccd 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1680,6 +1680,7 @@ static inline bool migration_bitmap_clear_dirty(RAMState
*rs,
return ret;
}
+/* Must be with rcu read lock held */
static void migration_bitmap_sync_range(RAMState *rs, RAMBlock *rb,
ram_addr_t start, ram_addr_t length)
{
--
2.17.1
- [Qemu-devel] [PATCH 00/11] kvm/migration: support KVM_CLEAR_DIRTY_LOG, Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 01/11] migration: No need to take rcu during sync_dirty_bitmap,
Peter Xu <=
- [Qemu-devel] [PATCH 02/11] memory: Remove memory_region_get_dirty(), Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 03/11] memory: Don't set migration bitmap when without migration, Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 04/11] bitmap: Add bitmap_copy_with_{src|dst}_offset(), Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 05/11] memory: Pass mr into snapshot_and_clear_dirty, Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 06/11] memory: Introduce memory listener hook log_clear(), Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 07/11] kvm: Update comments for sync_dirty_bitmap, Peter Xu, 2019/05/08
- [Qemu-devel] [PATCH 08/11] kvm: Persistent per kvmslot dirty bitmap, Peter Xu, 2019/05/08