Commit 49110174 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Kevin Wolf
Browse files

AioContext: acquire/release AioContext during aio_poll 



This is the first step in pushing down acquire/release, and will let
rfifolock drop the contention callback feature.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1424449612-18215-3-git-send-email-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent e98ab097

aio-posix.c

+9 −0
Original line number Diff line number Diff line
@@ -238,6 +238,7 @@ bool aio_poll(AioContext *ctx, bool blocking) 
    bool progress;

    int64_t timeout;



    aio_context_acquire(ctx);

    was_dispatching = ctx->dispatching;

    progress = false;
@@ -267,7 +268,13 @@ bool aio_poll(AioContext *ctx, bool blocking) 
    timeout = blocking ? aio_compute_timeout(ctx) : 0;



    /* wait until next event */

    if (timeout) {

        aio_context_release(ctx);

    }

    ret = qemu_poll_ns((GPollFD *)pollfds, npfd, timeout);

    if (timeout) {

        aio_context_acquire(ctx);

    }



    /* if we have any readable fds, dispatch event */

    if (ret > 0) {
@@ -286,5 +293,7 @@ bool aio_poll(AioContext *ctx, bool blocking) 
    }



    aio_set_dispatching(ctx, was_dispatching);

    aio_context_release(ctx);



    return progress;

}

aio-win32.c

+8 −0
Original line number Diff line number Diff line
@@ -283,6 +283,7 @@ bool aio_poll(AioContext *ctx, bool blocking) 
    int count;

    int timeout;



    aio_context_acquire(ctx);

    have_select_revents = aio_prepare(ctx);

    if (have_select_revents) {

        blocking = false;
@@ -323,7 +324,13 @@ bool aio_poll(AioContext *ctx, bool blocking) 


        timeout = blocking

            ? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;

        if (timeout) {

            aio_context_release(ctx);

        }

        ret = WaitForMultipleObjects(count, events, FALSE, timeout);

        if (timeout) {

            aio_context_acquire(ctx);

        }

        aio_set_dispatching(ctx, true);



        if (first && aio_bh_poll(ctx)) {
@@ -349,5 +356,6 @@ bool aio_poll(AioContext *ctx, bool blocking) 
    progress |= timerlistgroup_run_timers(&ctx->tlg);



    aio_set_dispatching(ctx, was_dispatching);

    aio_context_release(ctx);

    return progress;

}

include/block/aio.h

+7 −6
Original line number Diff line number Diff line
@@ -118,13 +118,14 @@ void aio_context_ref(AioContext *ctx); 
void aio_context_unref(AioContext *ctx);



/* Take ownership of the AioContext.  If the AioContext will be shared between

 * threads, a thread must have ownership when calling aio_poll().

 * threads, and a thread does not want to be interrupted, it will have to

 * take ownership around calls to aio_poll().  Otherwise, aio_poll()

 * automatically takes care of calling aio_context_acquire and

 * aio_context_release.

 *

 * Note that multiple threads calling aio_poll() means timers, BHs, and

 * callbacks may be invoked from a different thread than they were registered

 * from.  Therefore, code must use AioContext acquire/release or use

 * fine-grained synchronization to protect shared state if other threads will

 * be accessing it simultaneously.

 * Access to timers and BHs from a thread that has not acquired AioContext

 * is possible.  Access to callbacks for now must be done while the AioContext

 * is owned by the thread (FIXME).

 */

void aio_context_acquire(AioContext *ctx);