Merging upstream version 6.8.9.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/Documentation/admin-guide/mm/zswap.rst b/Documentation/admin-guide/mm/zswap.rst
index 45b98390e9..b42132969e 100644
--- a/Documentation/admin-guide/mm/zswap.rst
+++ b/Documentation/admin-guide/mm/zswap.rst
@@ -153,6 +153,26 @@ attribute, e. g.::
 
 Setting this parameter to 100 will disable the hysteresis.
 
+Some users cannot tolerate the swapping that comes with zswap store failures
+and zswap writebacks. Swapping can be disabled entirely (without disabling
+zswap itself) on a cgroup-basis as follows:
+
+	echo 0 > /sys/fs/cgroup/<cgroup-name>/memory.zswap.writeback
+
+Note that if the store failures are recurring (for e.g if the pages are
+incompressible), users can observe reclaim inefficiency after disabling
+writeback (because the same pages might be rejected again and again).
+
+When there is a sizable amount of cold memory residing in the zswap pool, it
+can be advantageous to proactively write these cold pages to swap and reclaim
+the memory for other use cases. By default, the zswap shrinker is disabled.
+User can enable it as follows:
+
+  echo Y > /sys/module/zswap/parameters/shrinker_enabled
+
+This can be enabled at the boot time if ``CONFIG_ZSWAP_SHRINKER_DEFAULT_ON`` is
+selected.
+
 A debugfs interface is provided for various statistic about pool size, number
 of pages stored, same-value filled pages and various counters for the reasons
 pages are rejected.