Messages in this thread | | | Subject | Re: [Lsf] [RFC] writeback and cgroup | From | Peter Zijlstra <> | Date | Sat, 14 Apr 2012 14:15:16 +0200 |
| |
On Wed, 2012-04-04 at 14:23 -0500, Steve French wrote: > Current use of bdi is a little hard to understand since > there are 25+ fields in the structure.
Filesystems only need a small fraction of those.
In particular,
backing_dev_info::name -- string backing_dev_info::ra_pages -- number of read-ahead-pages backing_dev_info::capability -- see BDI_CAP_*
One should properly initialize/destroy the thing using:
bdi_init()/bdi_destroy()
Furthermore, it has hooks into the regular page-writeback stuff:
test_{set,clear}_page_writeback()/bdi_writeout_inc() set_page_dirty()/account_page_dirtied() but also allows filesystems to do custom stuff, see FUSE for example.
The only other bit is the pressure valve, aka. {set,clear}_bdi_congested(). Which really is rather broken and of dubious value.
| |