On (08/15/14 11:27), Chao Yu wrote:
> Now we have supported handling discard request which is sended by filesystem,
> but no interface could be used to show information of discard.
> This patch adds num_discards to stat discarded pages, then export it to sysfs
> for displaying.
>
a side question: we account discarded pages via slot free notify in
notify_free and via req_discard in num_discards. how about accounting
both of them in num_discards? because, after all, they account a number
of discarded pages (zram_free_page()). or there any particular reason we
want to distinguish.
-ss
> Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-block-zram | 10 ++++++++++
> drivers/block/zram/zram_drv.c | 3 +++
> drivers/block/zram/zram_drv.h | 1 +
> 3 files changed, 14 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
> index 70ec992..fa8936e 100644
> --- a/Documentation/ABI/testing/sysfs-block-zram
> +++ b/Documentation/ABI/testing/sysfs-block-zram
> @@ -57,6 +57,16 @@ Description:
> The failed_writes file is read-only and specifies the number of
> failed writes happened on this device.
>
> +
> +What: /sys/block/zram<id>/num_discards
> +Date: August 2014
> +Contact: Chao Yu <chao2.yu@xxxxxxxxxxx>
> +Description:
> + The num_discards file is read-only and specifies the number of
> + physical blocks which are discarded by this device. These blocks
> + are included in discard request which is sended by filesystem as
> + the blocks are no longer used.
> +
> What: /sys/block/zram<id>/max_comp_streams
> Date: February 2014
> Contact: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index d00831c..904e7a5 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -606,6 +606,7 @@ static void zram_bio_discard(struct zram *zram, u32 index,
> bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
> zram_free_page(zram, index);
> bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
> + atomic64_inc(&zram->stats.num_discards);
> index++;
> n -= PAGE_SIZE;
> }
> @@ -866,6 +867,7 @@ ZRAM_ATTR_RO(num_reads);
> ZRAM_ATTR_RO(num_writes);
> ZRAM_ATTR_RO(failed_reads);
> ZRAM_ATTR_RO(failed_writes);
> +ZRAM_ATTR_RO(num_discards);
> ZRAM_ATTR_RO(invalid_io);
> ZRAM_ATTR_RO(notify_free);
> ZRAM_ATTR_RO(zero_pages);
> @@ -879,6 +881,7 @@ static struct attribute *zram_disk_attrs[] = {
> &dev_attr_num_writes.attr,
> &dev_attr_failed_reads.attr,
> &dev_attr_failed_writes.attr,
> + &dev_attr_num_discards.attr,
> &dev_attr_invalid_io.attr,
> &dev_attr_notify_free.attr,
> &dev_attr_zero_pages.attr,
> diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
> index e0f725c..2994aaf 100644
> --- a/drivers/block/zram/zram_drv.h
> +++ b/drivers/block/zram/zram_drv.h
> @@ -86,6 +86,7 @@ struct zram_stats {
> atomic64_t num_writes; /* --do-- */
> atomic64_t failed_reads; /* can happen when memory is too low */
> atomic64_t failed_writes; /* can happen when memory is too low */
> + atomic64_t num_discards; /* no. of discarded pages */
> atomic64_t invalid_io; /* non-page-aligned I/O requests */
> atomic64_t notify_free; /* no. of swap slot free notifications */
> atomic64_t zero_pages; /* no. of zero filled pages */
> --
> 2.0.1.474.g72c7794
>
>
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