Re: [PATCH 5/9] writeback: consolidate variable names in balance_dirty_pages()

Jan Kara
2011-06-30T17:26:50Z

On Wed 29-06-11 22:52:50, Wu Fengguang wrote:
> Introduce
>
> nr_dirty = NR_FILE_DIRTY + NR_WRITEBACK + NR_UNSTABLE_NFS
>
> in order to simplify many tests in the following patches.
>
> balance_dirty_pages() will eventually care only about the dirty sums
> besides nr_writeback.
Looks OK.
Acked-by: Jan Kara <jack@suse.cz>

Honza
>
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> ---
> mm/page-writeback.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> --- linux-next.orig/mm/page-writeback.c 2011-06-20 00:16:58.000000000 +0800
> +++ linux-next/mm/page-writeback.c 2011-06-20 00:17:06.000000000 +0800
> @@ -560,8 +560,9 @@ static void bdi_update_bandwidth(struct
> static void balance_dirty_pages(struct address_space *mapping,
> unsigned long write_chunk)
> {
> - long nr_reclaimable, bdi_nr_reclaimable;
> - long nr_writeback, bdi_nr_writeback;
> + unsigned long nr_reclaimable, bdi_nr_reclaimable;
> + unsigned long nr_dirty; /* = file_dirty + writeback + unstable_nfs */
> + unsigned long bdi_dirty;
> unsigned long background_thresh;
> unsigned long dirty_thresh;
> unsigned long bdi_thresh;
> @@ -574,7 +575,7 @@ static void balance_dirty_pages(struct a
> for (;;) {
> nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
> global_page_state(NR_UNSTABLE_NFS);
> - nr_writeback = global_page_state(NR_WRITEBACK);
> + nr_dirty = nr_reclaimable + global_page_state(NR_WRITEBACK);
>
> global_dirty_limits(&background_thresh, &dirty_thresh);
>
> @@ -583,8 +584,7 @@ static void balance_dirty_pages(struct a
> * catch-up. This avoids (excessively) small writeouts
> * when the bdi limits are ramping up.
> */
> - if (nr_reclaimable + nr_writeback <=
> - (background_thresh + dirty_thresh) / 2)
> + if (nr_dirty <= (background_thresh + dirty_thresh) / 2)
> break;
>
> bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh);
> @@ -602,10 +602,12 @@ static void balance_dirty_pages(struct a
> */
> if (bdi_thresh < 2*bdi_stat_error(bdi)) {
> bdi_nr_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE);
> - bdi_nr_writeback = bdi_stat_sum(bdi, BDI_WRITEBACK);
> + bdi_dirty = bdi_nr_reclaimable +
> + bdi_stat_sum(bdi, BDI_WRITEBACK);
> } else {
> bdi_nr_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE);
> - bdi_nr_writeback = bdi_stat(bdi, BDI_WRITEBACK);
> + bdi_dirty = bdi_nr_reclaimable +
> + bdi_stat(bdi, BDI_WRITEBACK);
> }
>
> /*
> @@ -614,9 +616,8 @@ static void balance_dirty_pages(struct a
> * bdi or process from holding back light ones; The latter is
> * the last resort safeguard.
> */
> - dirty_exceeded =
> - (bdi_nr_reclaimable + bdi_nr_writeback > bdi_thresh)
> - || (nr_reclaimable + nr_writeback > dirty_thresh);
> + dirty_exceeded = (bdi_dirty > bdi_thresh) ||
> + (nr_dirty > dirty_thresh);
>
> if (!dirty_exceeded)
> break;
>
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR