From 10447b60bee52f026bdbc5fe2aca52d0492fc91d Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date: Wed, 15 Apr 2015 16:15:52 -0700
Subject: [PATCH] zram: remove `num_migrated' device attr
This patch introduces rework to zram stats. We have per-stat sysfs nodes,
and it makes things a bit hard to use in user space: it doesn't give an
immediate stats 'snapshot', it requires user space to use more syscalls -
open, read, close for every stat file, with appropriate error checks on
every step, etc.
First, zram now accounts block layer statistics, available in
/sys/block/zram<id>/stat and /proc/diskstats files. So some new stats are
available (see Documentation/block/stat.txt), besides, zram's activities
now can be monitored by sysstat's iostat or similar tools.
Example:
cat /sys/block/zram0/stat
248 0 1984 0 251029 0 2008232 5120 0 5116 5116
Second, group currently exported on per-stat basis nodes into two
categories (files):
-- zram<id>/io_stat
accumulates device's IO stats, that are not accounted by block layer,
and contains:
failed_reads
failed_writes
invalid_io
notify_free
Example:
cat /sys/block/zram0/io_stat
0 0 0 652572
-- zram<id>/mm_stat
accumulates zram mm stats and contains:
orig_data_size
compr_data_size
mem_used_total
mem_limit
mem_used_max
zero_pages
num_migrated
Example:
cat /sys/block/zram0/mm_stat
434634752 270288572 279158784 0 579895296 15060 0
per-stat sysfs nodes are now considered to be deprecated and we plan to
remove them (and clean up some of the existing stat code) in two years (as
of now, there is no warning printed to syslog about deprecated stats being
used). User space is advised to use the above mentioned 3 files.
This patch (of 7):
Remove sysfs `num_migrated' attribute. We are moving away from per-stat
device attrs towards 3 stat files that will accumulate io and mm stats in
a format similar to block layer statistics in /sys/block/<dev>/stat. That
will be easier to use in user space, and reduce the number of syscalls
needed to read zram device statistics.
`num_migrated' will return back in zram<id>/mm_stat file.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/ABI/testing/sysfs-block-zram | 7 -------
drivers/block/zram/zram_drv.c | 2 --
2 files changed, 9 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index bede9028a5a0d..91ad7071b9e84 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -149,10 +149,3 @@ Description:
The compact file is write-only and trigger compaction for
allocator zrm uses. The allocator moves some objects so that
it could free fragment space.
-
-What: /sys/block/zram<id>/num_migrated
-Date: August 2015
-Contact: Minchan Kim <minchan@kernel.org>
-Description:
- The compact file is read-only and shows how many object
- migrated by compaction.
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 1626961fdb2f1..f416e3ce63922 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1057,7 +1057,6 @@ ZRAM_ATTR_RO(invalid_io);
ZRAM_ATTR_RO(notify_free);
ZRAM_ATTR_RO(zero_pages);
ZRAM_ATTR_RO(compr_data_size);
-ZRAM_ATTR_RO(num_migrated);
static struct attribute *zram_disk_attrs[] = {
&dev_attr_disksize.attr,
@@ -1067,7 +1066,6 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_num_writes.attr,
&dev_attr_failed_reads.attr,
&dev_attr_failed_writes.attr,
- &dev_attr_num_migrated.attr,
&dev_attr_compact.attr,
&dev_attr_invalid_io.attr,
&dev_attr_notify_free.attr,
--
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