Re: [PATCH 11/15] writeback: skip balance_dirty_pages() for in-memory fs

Jan Kara
2011-06-13T13:43:01Z

On Sat 11-06-11 21:07:31, Wu Fengguang wrote:
> > @@ -495,6 +490,9 @@ static void balance_dirty_pages(struct a
> > bool dirty_exceeded = false;
> > struct backing_dev_info *bdi = mapping->backing_dev_info;
> >
> > + if (!bdi_cap_account_dirty(bdi))
> > + return;
> > +
> > for (;;) {
> > struct writeback_control wbc = {
> > .sync_mode = WB_SYNC_NONE,
> >
>
> Update: it's slightly better to do early return in
> balance_dirty_pages_ratelimited_nr(). This way the tmpfs dirties won't
> unnecessarily disturb the per-cpu bdp_ratelimits counters.
Yup, makes sense to me.

Acked-by: Jan Kara <jack@suse.cz>

Honza

> --- linux-next.orig/mm/page-writeback.c 2011-06-11 17:52:59.000000000 +0800
> +++ linux-next/mm/page-writeback.c 2011-06-11 17:53:53.000000000 +0800
> @@ -1098,9 +1098,6 @@ static void balance_dirty_pages(struct a
> struct backing_dev_info *bdi = mapping->backing_dev_info;
> unsigned long start_time = jiffies;
>
> - if (!bdi_cap_account_dirty(bdi))
> - return;
> -
> for (;;) {
> nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
> global_page_state(NR_UNSTABLE_NFS);
> @@ -1237,9 +1234,13 @@ static DEFINE_PER_CPU(unsigned long, bdp
> void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
> unsigned long nr_pages_dirtied)
> {
> + struct backing_dev_info *bdi = mapping->backing_dev_info;
> unsigned long ratelimit;
> unsigned long *p;
>
> + if (!bdi_cap_account_dirty(bdi))
> + return;
> +
> ratelimit = ratelimit_pages;
> if (mapping->backing_dev_info->dirty_exceeded)
> ratelimit = 8;
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR