block_dump: remove comments in docs

Now block_dump feature is gone, remove all comments in docs.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210313030146.2882027-4-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 0 insertions, 11 deletions

diff --git a/Documentation/admin-guide/laptops/laptop-mode.rst b/Documentation/admin-guide/laptops/laptop-mode.rst
index c984c4262f2e..b61cc601d298 100644
--- a/Documentation/admin-guide/laptops/laptop-mode.rst
+++ b/Documentation/admin-guide/laptops/laptop-mode.rst
@@ -101,17 +101,6 @@ this results in concentration of disk activity in a small time interval which
 occurs only once every 10 minutes, or whenever the disk is forced to spin up by
 a cache miss. The disk can then be spun down in the periods of inactivity.
 
-If you want to find out which process caused the disk to spin up, you can
-gather information by setting the flag /proc/sys/vm/block_dump. When this flag
-is set, Linux reports all disk read and write operations that take place, and
-all block dirtyings done to files. This makes it possible to debug why a disk
-needs to spin up, and to increase battery life even more. The output of
-block_dump is written to the kernel output, and it can be retrieved using
-"dmesg". When you use block_dump and your kernel logging level also includes
-kernel debugging messages, you probably want to turn off klogd, otherwise
-the output of block_dump will be logged, causing disk activity that is not
-normally there.
-
 
 Configuration
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