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| author | Zhi Yong Wu | 2012-04-02 12:59:34 +0200 |
|---|---|---|
| committer | Kevin Wolf | 2012-04-05 14:54:40 +0200 |
| commit | 498e386c58497f621a37301ea6e8ca886f9f2e07 (patch) | |
| tree | d95efbf999cf4bbc38a6306a68457ec1b6c8e8a3 /block.c | |
| parent | Use DMADirection type for dma_bdrv_io (diff) | |
| download | qemu-498e386c58497f621a37301ea6e8ca886f9f2e07.tar.gz qemu-498e386c58497f621a37301ea6e8ca886f9f2e07.tar.xz qemu-498e386c58497f621a37301ea6e8ca886f9f2e07.zip | |
block: disable I/O throttling on sync api
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 20 |
1 files changed, 20 insertions, 0 deletions
@@ -1463,6 +1463,17 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, qemu_iovec_init_external(&qiov, &iov, 1); + /** + * 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); @@ -1969,10 +1980,19 @@ static int guess_disk_lchs(BlockDriverState *bs, struct partition *p; uint32_t nr_sects; uint64_t nb_sectors; + bool enabled; bdrv_get_geometry(bs, &nb_sectors); + /** + * The function will be invoked during startup not only in sync I/O mode, + * but also in async I/O mode. So the I/O throttling function has to + * be disabled temporarily here, not permanently. + */ + enabled = bs->io_limits_enabled; + bs->io_limits_enabled = false; ret = bdrv_read(bs, 0, buf, 1); + bs->io_limits_enabled = enabled; if (ret < 0) return -1; /* test msdos magic */ |