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authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2016-05-20 17:00:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 17:58:30 -0700
commit623e47fc64f8de480b322b7ed68855f97137e2a5 (patch)
tree0d44e61d20246d5a5329f0e1a84ac78d06668e83 /drivers/block
parent43209ea2d17aae1540d4e28274e36404f72702f2 (diff)
zram: introduce per-device debug_stat sysfs node
debug_stat sysfs is read-only and represents various debugging data that zram developers may need. This file is not meant to be used by anyone else: its content is not documented and will change any time w/o any notice. Therefore, the output of debug_stat file contains a version string. To avoid any confusion, we will increase the version number every time we modify the output. At the moment this file exports only one value -- the number of re-compressions, IOW, the number of times compression fast path has failed. This stat is temporary any will be useful in case if any per-cpu compression streams regressions will be reported. Link: http://lkml.kernel.org/r/20160513230834.GB26763@bbox Link: http://lkml.kernel.org/r/20160511134553.12655-1-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/zram/zram_drv.c21
-rw-r--r--drivers/block/zram/zram_drv.h1
2 files changed, 22 insertions, 0 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 8fcfbebe79cd..8fcad8b761f1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -435,8 +435,26 @@ static ssize_t mm_stat_show(struct device *dev,
return ret;
}
+static ssize_t debug_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int version = 1;
+ struct zram *zram = dev_to_zram(dev);
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ ret = scnprintf(buf, PAGE_SIZE,
+ "version: %d\n%8llu\n",
+ version,
+ (u64)atomic64_read(&zram->stats.writestall));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
static DEVICE_ATTR_RO(io_stat);
static DEVICE_ATTR_RO(mm_stat);
+static DEVICE_ATTR_RO(debug_stat);
ZRAM_ATTR_RO(num_reads);
ZRAM_ATTR_RO(num_writes);
ZRAM_ATTR_RO(failed_reads);
@@ -719,6 +737,8 @@ compress_again:
zcomp_strm_release(zram->comp, zstrm);
zstrm = NULL;
+ atomic64_inc(&zram->stats.writestall);
+
handle = zs_malloc(meta->mem_pool, clen,
GFP_NOIO | __GFP_HIGHMEM);
if (handle)
@@ -1181,6 +1201,7 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_comp_algorithm.attr,
&dev_attr_io_stat.attr,
&dev_attr_mm_stat.attr,
+ &dev_attr_debug_stat.attr,
NULL,
};
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 06b1636f4722..3f5bf66a27e4 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -85,6 +85,7 @@ struct zram_stats {
atomic64_t zero_pages; /* no. of zero filled pages */
atomic64_t pages_stored; /* no. of pages currently stored */
atomic_long_t max_used_pages; /* no. of maximum pages stored */
+ atomic64_t writestall; /* no. of write slow paths */
};
struct zram_meta {