Commit 498e386c authored by Zhi Yong Wu's avatar Zhi Yong Wu Committed by Kevin Wolf
Browse files

block: disable I/O throttling on sync api 



Signed-off-by: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: default avatarZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 43cf8ae6

block.c

+20 −0
Original line number Diff line number Diff line
@@ -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 */