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[Qemu-devel] [PATCH v2 03/15] migration: No need to take rcu during sync
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH v2 03/15] migration: No need to take rcu during sync_dirty_bitmap |
Date: |
Mon, 20 May 2019 11:08:27 +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>
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 4c60869226..05f9f36c7c 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1678,6 +1678,7 @@ 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 length)
{
--
2.17.1
- [Qemu-devel] [PATCH v2 00/15] kvm/migration: support KVM_CLEAR_DIRTY_LOG, Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 01/15] checkpatch: Allow SPDX-License-Identifier, Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 03/15] migration: No need to take rcu during sync_dirty_bitmap,
Peter Xu <=
- [Qemu-devel] [PATCH v2 04/15] memory: Remove memory_region_get_dirty(), Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 05/15] memory: Don't set migration bitmap when without migration, Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 02/15] linux-headers: Update to Linux 5.2-rc1, Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 06/15] bitmap: Add bitmap_copy_with_{src|dst}_offset(), Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 07/15] memory: Pass mr into snapshot_and_clear_dirty, Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 09/15] kvm: Update comments for sync_dirty_bitmap, Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 08/15] memory: Introduce memory listener hook log_clear(), Peter Xu, 2019/05/19
- [Qemu-devel] [PATCH v2 10/15] kvm: Persistent per kvmslot dirty bitmap, Peter Xu, 2019/05/19