mm: add /sys/class/bdi/<bdi>/min_bytes knob

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bdi has two existing knobs to limit the amount of dirty memory:
min_ratio and max_ratio. However the granularity of the knobs is limited
and often it is more convenient to specify limits in terms of bytes.
This change adds the min_bytes knob.

It does not store the min_bytes value, instead it converts the max_bytes
value to a ratio. The value is therefore more an approximation than an
absolute value.

It also maintains the sum over all the bdi min_ratio values stored in
the variable bdi_min_ratio.

Link: https://lkml.kernel.org/r/20221119005215.3052436-14-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Cc: Chris Mason <clm@meta.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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Stefan Roesch 2022-11-18 16:52:08 -08:00 • committed by Andrew Morton

parent 803c980505

commit 9c84819bd6

1 changed files with 29 additions and 0 deletions

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mm/backing-dev.c

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