From 6b98bd649520d07df4d1b7a0a54ac73bf178519c Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 7 Apr 2016 18:33:34 +0200 Subject: block: plug whole tree at once, introduce bdrv_io_unplugged_begin/end Extract the handling of io_plug "depth" from linux-aio.c and let the main bdrv_drain loop do nothing but wait on I/O. Like the two newly introduced functions, bdrv_io_plug and bdrv_io_unplug now operate on all children. The visit order is now symmetrical between plug and unplug, making it possible for formats to implement plug/unplug. Reviewed-by: Fam Zheng Signed-off-by: Paolo Bonzini Acked-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/io.c | 76 ++++++++++++++++++++++++++++++++++++++++++------------- block/linux-aio.c | 13 ++++------ block/raw-aio.h | 2 +- block/raw-posix.c | 16 +----------- 4 files changed, 65 insertions(+), 42 deletions(-) (limited to 'block') diff --git a/block/io.c b/block/io.c index b798040e52..b903270115 100644 --- a/block/io.c +++ b/block/io.c @@ -253,7 +253,6 @@ static void bdrv_drain_poll(BlockDriverState *bs) while (busy) { /* Keep iterating */ - bdrv_flush_io_queue(bs); busy = bdrv_requests_pending(bs); busy |= aio_poll(bdrv_get_aio_context(bs), busy); } @@ -307,20 +306,24 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs) void coroutine_fn bdrv_co_drain(BlockDriverState *bs) { bdrv_no_throttling_begin(bs); + bdrv_io_unplugged_begin(bs); bdrv_drain_recurse(bs); bdrv_co_yield_to_drain(bs); + bdrv_io_unplugged_end(bs); bdrv_no_throttling_end(bs); } void bdrv_drain(BlockDriverState *bs) { bdrv_no_throttling_begin(bs); + bdrv_io_unplugged_begin(bs); bdrv_drain_recurse(bs); if (qemu_in_coroutine()) { bdrv_co_yield_to_drain(bs); } else { bdrv_drain_poll(bs); } + bdrv_io_unplugged_end(bs); bdrv_no_throttling_end(bs); } @@ -345,6 +348,7 @@ void bdrv_drain_all(void) block_job_pause(bs->job); } bdrv_no_throttling_begin(bs); + bdrv_io_unplugged_begin(bs); bdrv_drain_recurse(bs); aio_context_release(aio_context); @@ -369,7 +373,6 @@ void bdrv_drain_all(void) aio_context_acquire(aio_context); while ((bs = bdrv_next(bs))) { if (aio_context == bdrv_get_aio_context(bs)) { - bdrv_flush_io_queue(bs); if (bdrv_requests_pending(bs)) { busy = true; aio_poll(aio_context, busy); @@ -386,6 +389,7 @@ void bdrv_drain_all(void) AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); + bdrv_io_unplugged_end(bs); bdrv_no_throttling_end(bs); if (bs->job) { block_job_resume(bs->job); @@ -2756,31 +2760,67 @@ void bdrv_add_before_write_notifier(BlockDriverState *bs, void bdrv_io_plug(BlockDriverState *bs) { - BlockDriver *drv = bs->drv; - if (drv && drv->bdrv_io_plug) { - drv->bdrv_io_plug(bs); - } else if (bs->file) { - bdrv_io_plug(bs->file->bs); + BdrvChild *child; + + QLIST_FOREACH(child, &bs->children, next) { + bdrv_io_plug(child->bs); + } + + if (bs->io_plugged++ == 0 && bs->io_plug_disabled == 0) { + BlockDriver *drv = bs->drv; + if (drv && drv->bdrv_io_plug) { + drv->bdrv_io_plug(bs); + } } } void bdrv_io_unplug(BlockDriverState *bs) { - BlockDriver *drv = bs->drv; - if (drv && drv->bdrv_io_unplug) { - drv->bdrv_io_unplug(bs); - } else if (bs->file) { - bdrv_io_unplug(bs->file->bs); + BdrvChild *child; + + assert(bs->io_plugged); + if (--bs->io_plugged == 0 && bs->io_plug_disabled == 0) { + BlockDriver *drv = bs->drv; + if (drv && drv->bdrv_io_unplug) { + drv->bdrv_io_unplug(bs); + } + } + + QLIST_FOREACH(child, &bs->children, next) { + bdrv_io_unplug(child->bs); } } -void bdrv_flush_io_queue(BlockDriverState *bs) +void bdrv_io_unplugged_begin(BlockDriverState *bs) { - BlockDriver *drv = bs->drv; - if (drv && drv->bdrv_flush_io_queue) { - drv->bdrv_flush_io_queue(bs); - } else if (bs->file) { - bdrv_flush_io_queue(bs->file->bs); + BdrvChild *child; + + if (bs->io_plug_disabled++ == 0 && bs->io_plugged > 0) { + BlockDriver *drv = bs->drv; + if (drv && drv->bdrv_io_unplug) { + drv->bdrv_io_unplug(bs); + } + } + + QLIST_FOREACH(child, &bs->children, next) { + bdrv_io_unplugged_begin(child->bs); + } +} + +void bdrv_io_unplugged_end(BlockDriverState *bs) +{ + BdrvChild *child; + + assert(bs->io_plug_disabled); + QLIST_FOREACH(child, &bs->children, next) { + bdrv_io_unplugged_end(child->bs); + } + + if (--bs->io_plug_disabled == 0 && bs->io_plugged > 0) { + BlockDriver *drv = bs->drv; + if (drv && drv->bdrv_io_plug) { + drv->bdrv_io_plug(bs); + } } } diff --git a/block/linux-aio.c b/block/linux-aio.c index 805757e02e..102bf928af 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -220,19 +220,16 @@ void laio_io_plug(BlockDriverState *bs, void *aio_ctx) { struct qemu_laio_state *s = aio_ctx; - s->io_q.plugged++; + assert(!s->io_q.plugged); + s->io_q.plugged = 1; } -void laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug) +void laio_io_unplug(BlockDriverState *bs, void *aio_ctx) { struct qemu_laio_state *s = aio_ctx; - assert(s->io_q.plugged > 0 || !unplug); - - if (unplug && --s->io_q.plugged > 0) { - return; - } - + assert(s->io_q.plugged); + s->io_q.plugged = 0; if (!s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) { ioq_submit(s); } diff --git a/block/raw-aio.h b/block/raw-aio.h index 811e375018..0f5e35a7ec 100644 --- a/block/raw-aio.h +++ b/block/raw-aio.h @@ -43,7 +43,7 @@ BlockAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd, void laio_detach_aio_context(void *s, AioContext *old_context); void laio_attach_aio_context(void *s, AioContext *new_context); void laio_io_plug(BlockDriverState *bs, void *aio_ctx); -void laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug); +void laio_io_unplug(BlockDriverState *bs, void *aio_ctx); #endif #ifdef _WIN32 diff --git a/block/raw-posix.c b/block/raw-posix.c index 906d5c9411..50135ad383 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1345,17 +1345,7 @@ static void raw_aio_unplug(BlockDriverState *bs) #ifdef CONFIG_LINUX_AIO BDRVRawState *s = bs->opaque; if (s->use_aio) { - laio_io_unplug(bs, s->aio_ctx, true); - } -#endif -} - -static void raw_aio_flush_io_queue(BlockDriverState *bs) -{ -#ifdef CONFIG_LINUX_AIO - BDRVRawState *s = bs->opaque; - if (s->use_aio) { - laio_io_unplug(bs, s->aio_ctx, false); + laio_io_unplug(bs, s->aio_ctx); } #endif } @@ -1949,7 +1939,6 @@ BlockDriver bdrv_file = { .bdrv_refresh_limits = raw_refresh_limits, .bdrv_io_plug = raw_aio_plug, .bdrv_io_unplug = raw_aio_unplug, - .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -2398,7 +2387,6 @@ static BlockDriver bdrv_host_device = { .bdrv_refresh_limits = raw_refresh_limits, .bdrv_io_plug = raw_aio_plug, .bdrv_io_unplug = raw_aio_unplug, - .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -2528,7 +2516,6 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_refresh_limits = raw_refresh_limits, .bdrv_io_plug = raw_aio_plug, .bdrv_io_unplug = raw_aio_unplug, - .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -2664,7 +2651,6 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_refresh_limits = raw_refresh_limits, .bdrv_io_plug = raw_aio_plug, .bdrv_io_unplug = raw_aio_unplug, - .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, -- cgit v1.2.3