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[Qemu-block] [PATCH 03/18] block: access io_limits_disabled with atomic
From: |
Paolo Bonzini |
Subject: |
[Qemu-block] [PATCH 03/18] block: access io_limits_disabled with atomic ops |
Date: |
Thu, 25 May 2017 18:32:10 +0200 |
Reviewed-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Alberto Garcia <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/block-backend.c | 4 ++--
block/throttle-groups.c | 2 +-
include/sysemu/block-backend.h | 3 ++-
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/block-backend.c b/block/block-backend.c
index f3a6008..e50ec03 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1953,7 +1953,7 @@ static void blk_root_drained_begin(BdrvChild *child)
/* Note that blk->root may not be accessible here yet if we are just
* attaching to a BlockDriverState that is drained. Use child instead. */
- if (blk->public.io_limits_disabled++ == 0) {
+ if (atomic_fetch_inc(&blk->public.io_limits_disabled) == 0) {
throttle_group_restart_blk(blk);
}
}
@@ -1964,7 +1964,7 @@ static void blk_root_drained_end(BdrvChild *child)
assert(blk->quiesce_counter);
assert(blk->public.io_limits_disabled);
- --blk->public.io_limits_disabled;
+ atomic_dec(&blk->public.io_limits_disabled);
if (--blk->quiesce_counter == 0) {
if (blk->dev_ops && blk->dev_ops->drained_end) {
diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index b73e7a8..69bfbd4 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -240,7 +240,7 @@ static bool throttle_group_schedule_timer(BlockBackend
*blk, bool is_write)
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
bool must_wait;
- if (blkp->io_limits_disabled) {
+ if (atomic_read(&blkp->io_limits_disabled)) {
return false;
}
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 840ad61..24b63d6 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -80,7 +80,8 @@ typedef struct BlockBackendPublic {
CoQueue throttled_reqs[2];
/* Nonzero if the I/O limits are currently being ignored; generally
- * it is zero. */
+ * it is zero. Accessed with atomic operations.
+ */
unsigned int io_limits_disabled;
/* The following fields are protected by the ThrottleGroup lock.
--
1.8.3.1
- [Qemu-block] [PATCH v3 00/18] Block layer thread safety, part 1, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 04/18] block: access serialising_in_flight with atomic ops, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 03/18] block: access io_limits_disabled with atomic ops,
Paolo Bonzini <=
- [Qemu-block] [PATCH 06/18] block: access io_plugged with atomic ops, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 01/18] block: access copy_on_read with atomic ops, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 02/18] block: access quiesce_counter with atomic ops, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 05/18] block: access wakeup with atomic ops, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 07/18] throttle-groups: only start one coroutine from drained_begin, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 08/18] throttle-groups: do not use qemu_co_enter_next, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 09/18] throttle-groups: protect throttled requests with a CoMutex, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 10/18] util: add stats64 module, Paolo Bonzini, 2017/05/25
- [Qemu-block] [PATCH 11/18] block: use Stat64 for wr_highest_offset, Paolo Bonzini, 2017/05/25