diff options
authorEric Biggers <>2021-12-08 16:38:30 -0800
committerJens Axboe <>2022-01-09 18:59:10 -0700
commit1163010418a7f0c60c309743498cb6c5cd828ecc (patch)
parent849ab826e10531f106846e8e9eeae8d00a198f6e (diff)
docs: sysfs-block: document stable_writes
/sys/block/<disk>/queue/stable_writes is completely undocumented. Document it. Reviewed-by: Bart Van Assche <> Signed-off-by: Eric Biggers <> Link: Signed-off-by: Jens Axboe <>
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
index de3b86a3dfa5..288626e8cb53 100644
--- a/Documentation/ABI/stable/sysfs-block
+++ b/Documentation/ABI/stable/sysfs-block
@@ -516,6 +516,23 @@ Description:
scheduler module, if it isn't already present in the system.
+What: /sys/block/<disk>/queue/stable_writes
+Date: September 2020
+ [RW] This file will contain '1' if memory must not be modified
+ while it is being used in a write request to this device. When
+ this is the case and the kernel is performing writeback of a
+ page, the kernel will wait for writeback to complete before
+ allowing the page to be modified again, rather than allowing
+ immediate modification as is normally the case. This
+ restriction arises when the device accesses the memory multiple
+ times where the same data must be seen every time -- for
+ example, once to calculate a checksum and once to actually write
+ the data. If no such restriction exists, this file will contain
+ '0'. This file is writable for testing purposes.
What: /sys/block/<disk>/queue/throttle_sample_time
Date: March 2017