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[Qemu-devel] [PATCH 07/15] memory: avoid ref/unref in memory_region_find
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 07/15] memory: avoid ref/unref in memory_region_find |
Date: |
Thu, 22 Jan 2015 15:47:25 +0100 |
Do the entire lookup under RCU, which avoids atomic operations.
Signed-off-by: Paolo Bonzini <address@hidden>
---
memory.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/memory.c b/memory.c
index a844ced..577e87c 100644
--- a/memory.c
+++ b/memory.c
@@ -1828,7 +1828,8 @@ MemoryRegionSection memory_region_find(MemoryRegion *mr,
}
range = addrrange_make(int128_make64(addr), int128_make64(size));
- view = address_space_get_flatview(as);
+ rcu_read_lock();
+ view = atomic_rcu_read(&as->current_map);
fr = flatview_lookup(view, range);
if (!fr) {
flatview_unref(view);
@@ -1850,7 +1851,7 @@ MemoryRegionSection memory_region_find(MemoryRegion *mr,
ret.readonly = fr->readonly;
memory_region_ref(ret.mr);
- flatview_unref(view);
+ rcu_read_unlock();
return ret;
}
--
1.8.3.1
- [Qemu-devel] [PATCH 03/15] rcu: allow nesting of rcu_read_lock/rcu_read_unlock, (continued)
- [Qemu-devel] [PATCH 03/15] rcu: allow nesting of rcu_read_lock/rcu_read_unlock, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 05/15] memory: remove assertion on memory_region_destroy, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 06/15] memory: protect current_map by RCU, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 08/15] exec: introduce cpu_reload_memory_map, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 10/15] exec: RCUify AddressSpaceDispatch, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 04/15] rcu: add call_rcu, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 07/15] memory: avoid ref/unref in memory_region_find,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 12/15] exec: protect mru_block with RCU, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 11/15] rcu: introduce RCU-enabled QLIST, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 14/15] exec: convert ram_list to QLIST, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 13/15] cosmetic changes preparing for the following patches, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 09/15] exec: make iotlb RCU-friendly, Paolo Bonzini, 2015/01/22
- [Qemu-devel] [PATCH 15/15] Convert ram_list to RCU, Paolo Bonzini, 2015/01/22