summaryrefslogtreecommitdiff
path: root/Documentation/blockdev
diff options
context:
space:
mode:
authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2015-04-16 02:16:09 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-16 02:35:21 +0300
commit8f7d282c717acaae25245c61b6b60e8995ec4ef4 (patch)
tree619cd0a9f363bfccf911f0fe2fe892a5961e9f9b /Documentation/blockdev
parent4f2109f60881585dc04fa0b5657a60556576625c (diff)
downloadlinux-8f7d282c717acaae25245c61b6b60e8995ec4ef4.tar.xz
zram: deprecate zram attrs sysfs nodes
Add Documentation/ABI/obsolete/sysfs-block-zram file and list obsolete and deprecated attributes there. The patch also adds additional information to zram documentation and describes the basic strategy: - the existing RW nodes will be downgraded to WO nodes (in 4.11) - deprecated RO sysfs nodes will eventually be removed (in 4.11) Users will be additionally notified about deprecated attr usage by pr_warn_once() (added to every deprecated attr _show()), as suggested by Minchan Kim. User space is advised to use zram<id>/stat, zram<id>/io_stat and zram<id>/mm_stat files. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-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>
Diffstat (limited to 'Documentation/blockdev')
-rw-r--r--Documentation/blockdev/zram.txt16
1 files changed, 16 insertions, 0 deletions
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index 7920f4026d36..48a183e29988 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -128,6 +128,22 @@ mem_limit RW the maximum amount of memory ZRAM can use to store
num_migrated RO the number of objects migrated migrated by compaction
+WARNING
+=======
+per-stat sysfs attributes are considered to be deprecated.
+The basic strategy is:
+-- the existing RW nodes will be downgraded to WO nodes (in linux 4.11)
+-- deprecated RO sysfs nodes will eventually be removed (in linux 4.11)
+
+The list of deprecated attributes can be found here:
+Documentation/ABI/obsolete/sysfs-block-zram
+
+Basically, every attribute that has its own read accessible sysfs node
+(e.g. num_reads) *AND* is accessible via one of the stat files (zram<id>/stat
+or zram<id>/io_stat or zram<id>/mm_stat) is considered to be deprecated.
+
+User space is advised to use the following files to read the device statistics.
+
File /sys/block/zram<id>/stat
Represents block layer statistics. Read Documentation/block/stat.txt for