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.
v2: update zram document.
Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-block-zram | 10 ++++++++++
Documentation/blockdev/zram.txt | 1 +
drivers/block/zram/zram_drv.c | 3 +++
drivers/block/zram/zram_drv.h | 1 +
4 files changed, 15 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/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index 0595c3f..e50e18b 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -89,6 +89,7 @@ size of the disk when not in use so a huge zram is wasteful.
num_writes
failed_reads
failed_writes
+ num_discards
invalid_io
notify_free
zero_pages
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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