• Tejun Heo's avatar
    writeback: implement memcg wb_domain · 841710aa
    Tejun Heo authored
    Dirtyable memory is distributed to a wb (bdi_writeback) according to
    the relative bandwidth the wb is writing out in the whole system.
    This distribution is global - each wb is measured against all other
    wb's and gets the proportinately sized portion of the memory in the
    whole system.
    
    For cgroup writeback, the amount of dirtyable memory is scoped by
    memcg and thus each wb would need to be measured and controlled in its
    memcg.  IOW, a wb will belong to two writeback domains - the global
    and memcg domains.
    
    The previous patches laid the groundwork to support the two wb_domains
    and this patch implements memcg wb_domain.  memcg->cgwb_domain is
    initialized on css online and destroyed on css release,
    wb->memcg_completions is added, and __wb_writeout_inc() is updated to
    increment completions against both global and memcg wb_domains.
    
    The following patches will update balance_dirty_pages() and its
    subroutines to actually consider memcg wb_domain for throttling.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Cc: Jens Axboe <axboe@kernel.dk>
    Cc: Jan Kara <jack@suse.cz>
    Cc: Wu Fengguang <fengguang.wu@intel.com>
    Cc: Greg Thelen <gthelen@google.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
    841710aa
backing-dev-defs.h 6.1 KB