[PATCH] md: use REQ_NOIDLE flag in md_super_write()

Queue idling is used for the anticipation of immediate
sequencial I/O's but md_super_write() is a kind of one-
shot operation, coupled with md_super_wait(), so the
idling in this case will be just a waste of time.

Specifying REQ_NOIDLE prevents it. Instead of adding
the flag to submit_bio() directly, use pre-defined
macro WRITE_FLUSH_FUA.

Signed-off-by: Namhyung Kim
---
drivers/md/md.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index d97a62534798..8650e9a0ce7c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -848,7 +848,7 @@ void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
bio->bi_end_io = super_written;

atomic_inc(&mddev->pending_writes);
- submit_bio(REQ_WRITE | REQ_SYNC | REQ_FLUSH | REQ_FUA, bio);
+ submit_bio(WRITE_FLUSH_FUA, bio);
}

void md_super_wait(mddev_t *mddev)
--
1.7.6

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Re: [PATCH] md: use REQ_NOIDLE flag in md_super_write()

On Thu, 4 Aug 2011 00:57:57 +0900 Namhyung Kim wrote:

> Queue idling is used for the anticipation of immediate
> sequencial I/O's but md_super_write() is a kind of one-
> shot operation, coupled with md_super_wait(), so the
> idling in this case will be just a waste of time.
>
> Specifying REQ_NOIDLE prevents it. Instead of adding
> the flag to submit_bio() directly, use pre-defined
> macro WRITE_FLUSH_FUA.
>
> Signed-off-by: Namhyung Kim
> ---
> drivers/md/md.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index d97a62534798..8650e9a0ce7c 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -848,7 +848,7 @@ void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
> bio->bi_end_io = super_written;
>
> atomic_inc(&mddev->pending_writes);
> - submit_bio(REQ_WRITE | REQ_SYNC | REQ_FLUSH | REQ_FUA, bio);
> + submit_bio(WRITE_FLUSH_FUA, bio);
> }
>
> void md_super_wait(mddev_t *mddev)

Applied, thanks.

NeilBrown


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