81531225e5
I have observed the following case play out and lead to unnecessary relocations: 1. write a file across multiple block groups 2. delete the file 3. several block groups fall below the reclaim threshold 4. reclaim the first, moving extents into the others 5. reclaim the others which are now actually very full, leading to poor reclaim behavior with lots of writing, allocating new block groups, etc. I believe the risk of missing some reasonable reclaims is worth it when traded off against the savings of avoiding overfull reclaims. Going forward, it could be interesting to make the check more advanced (zoned aware, fragmentation aware, etc...) so that it can be a really strong signal both at extent delete and reclaim time. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.