On Tue 25-10-16 14:41:42, Josef Bacik wrote:
> Btrfs has no bounds except memory on the amount of dirty memory that we have
> in
> use for metadata. Historically we have used a special inode so we could take
> advantage of the balance_dirty_pages throttling that comes with using
> pagecache.
> However as we'd like to support different blocksizes it would be nice to not
> have to rely on pagecache, but still get the balance_dirty_pages throttling
> without having to do it ourselves.
>
> So introduce *METADATA_DIRTY_BYTES and *METADATA_WRITEBACK_BYTES. These are
> zone and bdi_writeback counters to keep track of how many bytes we have in
> flight for METADATA. We need to count in bytes as blocksizes could be
> percentages of pagesize. We simply convert the bytes to number of pages where
> it is needed for the throttling.
>
> Also introduce NR_METADATA_BYTES so we can keep track of the total amount of
> pages used for metadata on the system. This is also needed so things like
> dirty
> throttling know that this is dirtyable memory as well and easily reclaimed.
>
> Signed-off-by: Josef Bacik <jba...@fb.com>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <j...@suse.cz>
Honza
--
Jan Kara <j...@suse.com>
SUSE Labs, CR
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