Re: [PATCH v3 02/14] md: move two macros into md.h

NeilBrown
2017-03-24T05:57:47Z

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On Fri, Mar 17 2017, Ming Lei wrote:

> Both raid1 and raid10 share common resync
> block size and page count, so move them into md.h.

I don't think this is necessary.
These are just "magic" numbers. They don't have any real
meaning and so don't belong in md.h, or and .h file.

Possibly we should find more meaningful numbers, or make them auto-size
or something. I'm also happy for them to stay as they are for now.
But I don't think we should pretend that they are meaningful.

Thanks,
NeilBrown

>
> Signed-off-by: Ming Lei <tom.leiming@gmail.com>
> ---
> drivers/md/md.h | 5 +++++
> drivers/md/raid1.c | 2 --
> drivers/md/raid10.c | 3 ---
> 3 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index b8859cbf84b6..1d63239a1be4 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -715,4 +715,9 @@ static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
> !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
> mddev->queue->limits.max_write_same_sectors = 0;
> }
> +
> +/* Maximum size of each resync request */
> +#define RESYNC_BLOCK_SIZE (64*1024)
> +#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
> +
> #endif /* _MD_MD_H */
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 4a0b2ad5025e..908e2caeb704 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -94,10 +94,8 @@ static void r1bio_pool_free(void *r1_bio, void *data)
> kfree(r1_bio);
> }
>
> -#define RESYNC_BLOCK_SIZE (64*1024)
> #define RESYNC_DEPTH 32
> #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
> -#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
> #define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH)
> #define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
> #define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index b4a56a488668..2b40420299e3 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -125,9 +125,6 @@ static void r10bio_pool_free(void *r10_bio, void *data)
> kfree(r10_bio);
> }
>
> -/* Maximum size of each resync request */
> -#define RESYNC_BLOCK_SIZE (64*1024)
> -#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
> /* amount of memory to reserve for resync requests */
> #define RESYNC_WINDOW (1024*1024)
> /* maximum number of concurrent requests, memory permitting */
> --
> 2.9.3
>
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