On 1/3/20 11:58 PM, Song Liu wrote:
On Mon, Dec 23, 2019 at 1:49 AM <jgq516@xxxxxxxxx> wrote:From: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx> So far, IO serialization is used for two scenarios: 1. raid1 which enables write-behind mode, and there is rdev in the array which is multi-queue device and flaged with writemostly. 2. IO serialization is enabled or disabled by change serialize_policy. So introduce rdev_need_serial to check the first scenario. And for 1, IO serialization is enabled automatically while 2 is controlled manually. And it is possible that both scenarios are true, so for create serial pool, rdev/rdevs_init_serial should be separate from check if the pool existed or not. Then for destroy pool, we need to check if the pool is needed by other rdevs due to the first scenario. Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx> --- drivers/md/md.c | 71 +++++++++++++++++++++++++++++-------------------- 1 file changed, 42 insertions(+), 29 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 796cf70e1c9f..788559f42d43 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -147,28 +147,40 @@ static void rdevs_init_serial(struct mddev *mddev) } /* - * Create serial_info_pool for raid1 under conditions: - * 1. rdev is the first multi-queue device flaged with writemostly, - * also write-behind mode is enabled. - * 2. rdev is NULL, means want to enable serialization for all rdevs. + * rdev needs to enable serial stuffs if it meets the conditions: + * 1. it is multi-queue device flaged with writemostly. + * 2. the write-behind mode is enabled. + */ +static int rdev_need_serial(struct md_rdev *rdev) +{ + return (rdev && rdev->mddev->bitmap_info.max_write_behind > 0 &&I guess there is not need to check rdev here?
No, the rdev could be passed from mddev_create_serial_pool, and caller could set it to NULL, pls see patch 0003. Thanks, Guoqing
