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| -rw-r--r-- | Documentation/admin-guide/mm/zswap.rst | 20 |
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. |