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[RFC PATCH 1/5] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED
From: |
Emanuele Giuseppe Esposito |
Subject: |
[RFC PATCH 1/5] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED |
Date: |
Tue, 1 Mar 2022 09:21:09 -0500 |
Same as AIO_WAIT_WHILE macro, but if we are in the Main loop
do not release and then acquire ctx_ 's aiocontext.
Once all Aiocontext locks go away, this macro will replace
AIO_WAIT_WHILE.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
include/block/aio-wait.h | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h
index b39eefb38d..ff27fe4eab 100644
--- a/include/block/aio-wait.h
+++ b/include/block/aio-wait.h
@@ -59,10 +59,11 @@ typedef struct {
extern AioWait global_aio_wait;
/**
- * AIO_WAIT_WHILE:
+ * _AIO_WAIT_WHILE:
* @ctx: the aio context, or NULL if multiple aio contexts (for which the
* caller does not hold a lock) are involved in the polling condition.
* @cond: wait while this conditional expression is true
+ * @unlock: whether to unlock and then lock again @ctx
*
* Wait while a condition is true. Use this to implement synchronous
* operations that require event loop activity.
@@ -75,7 +76,7 @@ extern AioWait global_aio_wait;
* wait on conditions between two IOThreads since that could lead to deadlock,
* go via the main loop instead.
*/
-#define AIO_WAIT_WHILE(ctx, cond) ({ \
+#define _AIO_WAIT_WHILE(ctx, cond, unlock) ({ \
bool waited_ = false; \
AioWait *wait_ = &global_aio_wait; \
AioContext *ctx_ = (ctx); \
@@ -90,11 +91,11 @@ extern AioWait global_aio_wait;
assert(qemu_get_current_aio_context() == \
qemu_get_aio_context()); \
while ((cond)) { \
- if (ctx_) { \
+ if (unlock && ctx_) { \
aio_context_release(ctx_); \
} \
aio_poll(qemu_get_aio_context(), true); \
- if (ctx_) { \
+ if (unlock && ctx_) { \
aio_context_acquire(ctx_); \
} \
waited_ = true; \
@@ -103,6 +104,12 @@ extern AioWait global_aio_wait;
qatomic_dec(&wait_->num_waiters); \
waited_; })
+#define AIO_WAIT_WHILE(ctx, cond) \
+ _AIO_WAIT_WHILE(ctx, cond, true)
+
+#define AIO_WAIT_WHILE_UNLOCKED(ctx, cond) \
+ _AIO_WAIT_WHILE(ctx, cond, false)
+
/**
* aio_wait_kick:
* Wake up the main thread if it is waiting on AIO_WAIT_WHILE(). During
--
2.31.1
- [RFC PATCH 0/5] Removal of AioContext lock, bs->parents and ->children: proof of concept, Emanuele Giuseppe Esposito, 2022/03/01
- [RFC PATCH 2/5] introduce BDRV_POLL_WHILE_UNLOCKED, Emanuele Giuseppe Esposito, 2022/03/01
- [RFC PATCH 4/5] child_job_drained_poll: override polling condition only when in home thread, Emanuele Giuseppe Esposito, 2022/03/01
- [RFC PATCH 1/5] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED,
Emanuele Giuseppe Esposito <=
- [RFC PATCH 3/5] block/io.c: introduce bdrv_subtree_drained_{begin/end}_unlocked, Emanuele Giuseppe Esposito, 2022/03/01
- [RFC PATCH 5/5] test-bdrv-drain: ensure draining from main loop stops iothreads, Emanuele Giuseppe Esposito, 2022/03/01
- Re: [RFC PATCH 0/5] Removal of AioContext lock, bs->parents and ->children: proof of concept, Emanuele Giuseppe Esposito, 2022/03/01
- Re: [RFC PATCH 0/5] Removal of AioContext lock, bs->parents and ->children: proof of concept, Stefan Hajnoczi, 2022/03/02