From a0d64a61db602696f4f1895a890c65eda5b3b618 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Wed, 4 Nov 2015 15:15:36 +0200 Subject: [PATCH] throttle: Use bs->throttle_state instead of bs->io_limits_enabled There are two ways to check for I/O limits in a BlockDriverState: - bs->throttle_state: if this pointer is not NULL, it means that this BDS is member of a throttling group, its ThrottleTimers structure has been initialized and its I/O limits are ready to be applied. - bs->io_limits_enabled: if true it means that the throttle_state pointer is valid _and_ the limits are currently enabled. The latter is used in several places to check whether a BDS has I/O limits configured, but what it really checks is whether requests are being throttled or not. For example, io_limits_enabled can be temporarily set to false in cases like bdrv_read_unthrottled() without otherwise touching the throtting configuration of that BDS. This patch replaces bs->io_limits_enabled with bs->throttle_state in all cases where what we really want to check is the existence of I/O limits, not whether they are currently enabled or not. Signed-off-by: Alberto Garcia Signed-off-by: Kevin Wolf --- block.c | 6 +++--- block/qapi.c | 2 +- blockdev.c | 4 ++-- include/block/block_int.h | 5 ++++- 4 files changed, 10 insertions(+), 7 deletions(-) diff --git a/block.c b/block.c index 34935015dd..cffac75016 100644 --- a/block.c +++ b/block.c @@ -1907,7 +1907,7 @@ void bdrv_close(BlockDriverState *bs) } /* Disable I/O limits and drain all pending throttled requests */ - if (bs->io_limits_enabled) { + if (bs->throttle_state) { bdrv_io_limits_disable(bs); } @@ -3712,7 +3712,7 @@ void bdrv_detach_aio_context(BlockDriverState *bs) baf->detach_aio_context(baf->opaque); } - if (bs->io_limits_enabled) { + if (bs->throttle_state) { throttle_timers_detach_aio_context(&bs->throttle_timers); } if (bs->drv->bdrv_detach_aio_context) { @@ -3748,7 +3748,7 @@ void bdrv_attach_aio_context(BlockDriverState *bs, if (bs->drv->bdrv_attach_aio_context) { bs->drv->bdrv_attach_aio_context(bs, new_context); } - if (bs->io_limits_enabled) { + if (bs->throttle_state) { throttle_timers_attach_aio_context(&bs->throttle_timers, new_context); } diff --git a/block/qapi.c b/block/qapi.c index ec0f5139e2..89d4274177 100644 --- a/block/qapi.c +++ b/block/qapi.c @@ -64,7 +64,7 @@ BlockDeviceInfo *bdrv_block_device_info(BlockDriverState *bs, Error **errp) info->backing_file_depth = bdrv_get_backing_file_depth(bs); info->detect_zeroes = bs->detect_zeroes; - if (bs->io_limits_enabled) { + if (bs->throttle_state) { ThrottleConfig cfg; throttle_group_get_config(bs, &cfg); diff --git a/blockdev.c b/blockdev.c index 7645d491cb..3598b01419 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2361,14 +2361,14 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd, if (throttle_enabled(&cfg)) { /* Enable I/O limits if they're not enabled yet, otherwise * just update the throttling group. */ - if (!bs->io_limits_enabled) { + if (!bs->throttle_state) { bdrv_io_limits_enable(bs, has_group ? group : device); } else if (has_group) { bdrv_io_limits_update_group(bs, group); } /* Set the new throttling configuration */ bdrv_set_io_limits(bs, &cfg); - } else if (bs->io_limits_enabled) { + } else if (bs->throttle_state) { /* If all throttling settings are set to 0, disable I/O limits */ bdrv_io_limits_disable(bs); } diff --git a/include/block/block_int.h b/include/block/block_int.h index 6a3f64da12..603145a21d 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -390,7 +390,10 @@ struct BlockDriverState { /* number of in-flight serialising requests */ unsigned int serialising_in_flight; - /* I/O throttling */ + /* I/O throttling. + * throttle_state tells us if this BDS has I/O limits configured. + * io_limits_enabled tells us if they are currently being + * enforced, but it can be temporarily set to false */ CoQueue throttled_reqs[2]; bool io_limits_enabled; /* The following fields are protected by the ThrottleGroup lock.