On Mon, 2 Sep 2019, Huaisheng Ye wrote:
> From: Huaisheng Ye <[email protected]>
>
> The array bio_in_progress[2] only have chance to be increased and
> decreased with ssd mode. For pmem mode, they are not involved at all.
> So skip writecache_wait_for_ios in writecache_flush for pmem.
>
> Suggested-by: Doris Yu <[email protected]>
> Signed-off-by: Huaisheng Ye <[email protected]>
> ---
> drivers/md/dm-writecache.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> index c481947..d06b8aa 100644
> --- a/drivers/md/dm-writecache.c
> +++ b/drivers/md/dm-writecache.c
> @@ -726,7 +726,8 @@ static void writecache_flush(struct dm_writecache *wc)
> }
> writecache_commit_flushed(wc);
>
> - writecache_wait_for_ios(wc, WRITE);
> + if (!WC_MODE_PMEM(wc))
> + writecache_wait_for_ios(wc, WRITE);
>
> wc->seq_count++;
> pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
> --
> 1.8.3.1
I think this is not needed - wait_event in writecache_wait_for_ios exits
immediatelly if the condition is true.
This code path is not so hot that we would need microoptimizations like
this to avoid function calls.
Mikulas
