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authorMinchan Kim <minchan@kernel.org>2020-12-14 19:14:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:47 -0800
commit0d8359620d9be9823b6b9b3cf2dbe006cbfec594 (patch)
tree6bd834d7f3607b69ab0ff17480e31d3ee38b8b36 /Documentation/admin-guide/blockdev
parent95c9ae14a9b99a65956de80a1eefafcb901c0e9f (diff)
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zram: support page writeback
There is demand to writeback specific process pages to backing store instead of all idles pages in the system due to storage wear out concerns and to launching latency of apps which are most of the time idle but are critical for resume latency. This patch extends the writeback knob to support a specific page writeback. Link: https://lkml.kernel.org/r/20201020190506.3758660-1-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide/blockdev')
-rw-r--r--Documentation/admin-guide/blockdev/zram.rst5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index a6fd1f9b5faf..8f3cfa42e443 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -334,6 +334,11 @@ Admin can request writeback of those idle pages at right timing via::
With the command, zram writeback idle pages from memory to the storage.
+If admin want to write a specific page in zram device to backing device,
+they could write a page index into the interface.
+
+ echo "page_index=1251" > /sys/block/zramX/writeback
+
If there are lots of write IO with flash device, potentially, it has
flash wearout problem so that admin needs to design write limitation
to guarantee storage health for entire product life.