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[Qemu-devel] [PATCH v4 01/11] migration: No need to take rcu during sync
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH v4 01/11] migration: No need to take rcu during sync_dirty_bitmap |
Date: |
Mon, 3 Jun 2019 14:50:46 +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.
Reviewed-by: Paolo Bonzini <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
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..6fc49e5db5 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,
}
+/* Called with RCU critical section */
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 4c60869226..dc916042fb 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1678,6 +1678,7 @@ static inline bool migration_bitmap_clear_dirty(RAMState
*rs,
return ret;
}
+/* Called with RCU critical section */
static void migration_bitmap_sync_range(RAMState *rs, RAMBlock *rb,
ram_addr_t length)
{
--
2.17.1
- [Qemu-devel] [PATCH v4 00/11] kvm/migration: support KVM_CLEAR_DIRTY_LOG, Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 01/11] migration: No need to take rcu during sync_dirty_bitmap,
Peter Xu <=
- [Qemu-devel] [PATCH v4 02/11] memory: Remove memory_region_get_dirty(), Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 03/11] memory: Don't set migration bitmap when without migration, Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 04/11] bitmap: Add bitmap_copy_with_{src|dst}_offset(), Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 05/11] memory: Pass mr into snapshot_and_clear_dirty, Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 06/11] memory: Introduce memory listener hook log_clear(), Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 07/11] kvm: Update comments for sync_dirty_bitmap, Peter Xu, 2019/06/03
- [Qemu-devel] [PATCH v4 08/11] kvm: Persistent per kvmslot dirty bitmap, Peter Xu, 2019/06/03