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[Qemu-devel] [PATCH 10/10] async: optimize aio_bh_poll
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 10/10] async: optimize aio_bh_poll |
Date: |
Thu, 12 Jan 2017 17:55:31 +0100 |
Avoid entering the slow path of qemu_lockcnt_dec_and_lock if
no bottom half has to be deleted.
Reviewed-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
async.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/async.c b/async.c
index 2305e11..0d218ab 100644
--- a/async.c
+++ b/async.c
@@ -92,6 +92,7 @@ int aio_bh_poll(AioContext *ctx)
{
QEMUBH *bh, **bhp, *next;
int ret;
+ bool deleted = false;
qemu_lockcnt_inc(&ctx->list_lock);
@@ -112,9 +113,17 @@ int aio_bh_poll(AioContext *ctx)
bh->idle = 0;
aio_bh_call(bh);
}
+ if (bh->deleted) {
+ deleted = true;
+ }
}
/* remove deleted bhs */
+ if (!deleted) {
+ qemu_lockcnt_dec(&ctx->list_lock);
+ return ret;
+ }
+
if (qemu_lockcnt_dec_and_lock(&ctx->list_lock)) {
bhp = &ctx->first_bh;
while (*bhp) {
@@ -128,7 +137,6 @@ int aio_bh_poll(AioContext *ctx)
}
qemu_lockcnt_unlock(&ctx->list_lock);
}
-
return ret;
}
--
2.9.3
- [Qemu-devel] [PATCH v4 00/10] aio_context_acquire/release pushdown, part 1, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 03/10] aio: make ctx->list_lock a QemuLockCnt, subsuming ctx->walking_bh, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 01/10] aio: rename bh_lock to list_lock, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 05/10] aio-posix: split aio_dispatch_handlers out of aio_dispatch, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 04/10] qemu-thread: optimize QemuLockCnt with futexes on Linux, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 06/10] aio: tweak walking in dispatch phase, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 02/10] qemu-thread: introduce QemuLockCnt, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 07/10] aio-posix: remove walking_handlers, protecting AioHandler list with list_lock, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 09/10] aio: document locking, Paolo Bonzini, 2017/01/12
- [Qemu-devel] [PATCH 10/10] async: optimize aio_bh_poll,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 08/10] aio-win32: remove walking_handlers, protecting AioHandler list with list_lock, Paolo Bonzini, 2017/01/12
- Re: [Qemu-devel] [PATCH v4 00/10] aio_context_acquire/release pushdown, part 1, no-reply, 2017/01/12