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author | Stefan Hajnoczi <stefanha@redhat.com> | 2013-11-26 16:18:01 +0100 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2013-12-06 16:53:51 +0100 |
commit | d3fa923044321b2ccc12bbdedd582d2c49d958aa (patch) | |
tree | 47145dfcfa7f48ef385c1393a38c3496da8bae71 /aio-win32.c | |
parent | 0b06ef3bdd17742ae50c0662d3fe8ed944648890 (diff) | |
download | hqemu-d3fa923044321b2ccc12bbdedd582d2c49d958aa.zip hqemu-d3fa923044321b2ccc12bbdedd582d2c49d958aa.tar.gz |
aio: make aio_poll(ctx, true) block with no fds
This patch drops a special case where aio_poll(ctx, true) returns false
instead of blocking if no file descriptors are waiting on I/O. Now it
is possible to block in aio_poll() to wait for aio_notify().
This change eliminates busy waiting. bdrv_drain_all() used to rely on
busy waiting to completed throttled I/O requests but this is no longer
required so we can simplify aio_poll().
Note that aio_poll() still returns false when aio_notify() was used. In
other words, stopping a blocking aio_poll() wait is not considered
making progress.
Adjust test-aio /aio/bh/callback-delete/one which assumed aio_poll(ctx,
true) would immediately return false instead of blocking.
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'aio-win32.c')
-rw-r--r-- | aio-win32.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/aio-win32.c b/aio-win32.c index f9cfbb7..23f4e5b 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -161,11 +161,6 @@ bool aio_poll(AioContext *ctx, bool blocking) ctx->walking_handlers--; - /* early return if we only have the aio_notify() fd */ - if (count == 1) { - return progress; - } - /* wait until next event */ while (count > 0) { int ret; |