Commit 90c78624 authored Apr 07, 2016 by Kevin Wolf

block: Don't disable I/O throttling on sync requests



We had to disable I/O throttling with synchronous requests because we
didn't use to run timers in nested event loops when the code was
introduced. This isn't true any more, and throttling works just fine
even when using the synchronous API.

The removed code is in fact dead code since commit a8823a3b ('block: Use
blk_co_pwritev() for blk_write()') because I/O throttling can only be
set on the top layer, but BlockBackend always uses the coroutine
interface now instead of using the sync API emulation in block.c.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <1458660792-3035-2-git-send-email-kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

parent 26617924

block/io.c

+0 −11

Original line number	Diff line number	Diff line
		@@ -608,17 +608,6 @@ static int bdrv_prwv_co(BlockDriverState *bs, int64_t offset,
		.flags = flags,
		};

		/**
		* In sync call context, when the vcpu is blocked, this throttling timer
		* will not fire; so the I/O throttling function has to be disabled here
		* if it has been enabled.
		*/
		if (bs->io_limits_enabled) {
		fprintf(stderr, "Disabling I/O throttling on '%s' due "
		"to synchronous I/O.\n", bdrv_get_device_name(bs));
		bdrv_io_limits_disable(bs);
		}

		if (qemu_in_coroutine()) {
		/* Fast-path if already in coroutine context */
		bdrv_rw_co_entry(&rwco);