Ping -RongQing > -----邮件原件----- > 发件人: linux-fsdevel-owner@xxxxxxxxxxxxxxx [mailto:linux-fsdevel- > owner@xxxxxxxxxxxxxxx] 代表 Li RongQing > 发送时间: 2018年7月4日 16:58 > 收件人: linux-fsdevel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx > 抄送: viro@xxxxxxxxxxxxxxxxxx > 主题: [PATCH] fs/writeback: do memory cgroup related writeback firstly > > When a mechine has hundreds of memory cgroups, and some cgroups > generate more or less dirty pages, but a cgroup of them has lots of memory > pressure and always tries to reclaim dirty page, then it will trigger all cgroups > to writeback, which is less efficient: > > 1.if the used memory in a memory cgroup reaches its limit, it is useless to > writeback other cgroups. > 2.other cgroups can wait more time to merge write request > > so replace the full flush with flushing writeback of memory cgroup whose > tasks tries to reclaim memory and trigger writeback, if nothing is writeback, > then start a full flush > > Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx> > --- > fs/fs-writeback.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index > abafc9bd4622..a27efc4711a9 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -2001,6 +2001,28 @@ void wakeup_flusher_threads(enum wb_reason > reason) > if (blk_needs_flush_plug(current)) > blk_schedule_flush_plug(current); > > +#ifdef CONFIG_CGROUP_WRITEBACK > + if (reason == WB_REASON_VMSCAN) { > + int flush = 0; > + > + rcu_read_lock(); > + list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { > + struct bdi_writeback *wb = wb_find_current(bdi); > + > + if (wb && wb != &bdi->wb) { > + if (wb_has_dirty_io(wb)) { > + wb_start_writeback(wb, reason); > + flush++; > + } > + } > + } > + rcu_read_unlock(); > + > + if (flush) > + return; > + } > +#endif > + > rcu_read_lock(); > list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) > __wakeup_flusher_threads_bdi(bdi, reason); > -- > 2.16.2
