mm: add strictlimit knob

[karo-tx-linux.git] / Documentation / ABI / testing / sysfs-class-bdi

diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi
index d773d5697cf588349b74fd7d19e63983472b1632..3187a18af6da5bbbcc9ee2a0592e27f62ab1983c 100644 (file)
--- a/Documentation/ABI/testing/sysfs-class-bdi
+++ b/Documentation/ABI/testing/sysfs-class-bdi
@@ -53,3 +53,11 @@ stable_pages_required (read-only)
 
        If set, the backing device requires that all pages comprising a write
        request must not be changed until writeout is complete.
+
+strictlimit (read-write)
+
+       Forces per-BDI checks for the share of given device in the write-back
+       cache even before the global background dirty limit is reached. This
+       is useful in situations where the global limit is much higher than
+       affordable for given relatively slow (or untrusted) device. Turning
+       strictlimit on has no visible effect if max_ratio is equal to 100%.