Commit ba62d5cf authored by Kemeng Shi's avatar Kemeng Shi Committed by Andrew Morton
Browse files

writeback: add general function domain_dirty_avail to calculate dirty and avail of domain 

Add general function domain_dirty_avail to calculate dirty and avail for
either dirty limit or background writeback in either global domain or wb
domain.

Link: https://lkml.kernel.org/r/20240514125254.142203-3-shikemeng@huaweicloud.com


Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7c0c629b

mm/page-writeback.c

+34 −31
Original line number Diff line number Diff line
@@ -837,6 +837,34 @@ static void mdtc_calc_avail(struct dirty_throttle_control *mdtc, 
	mdtc->avail = filepages + min(headroom, other_clean);

}



static inline bool dtc_is_global(struct dirty_throttle_control *dtc)

{

	return mdtc_gdtc(dtc) == NULL;

}



/*

 * Dirty background will ignore pages being written as we're trying to

 * decide whether to put more under writeback.

 */

static void domain_dirty_avail(struct dirty_throttle_control *dtc,

			       bool include_writeback)

{

	if (dtc_is_global(dtc)) {

		dtc->avail = global_dirtyable_memory();

		dtc->dirty = global_node_page_state(NR_FILE_DIRTY);

		if (include_writeback)

			dtc->dirty += global_node_page_state(NR_WRITEBACK);

	} else {

		unsigned long filepages = 0, headroom = 0, writeback = 0;



		mem_cgroup_wb_stats(dtc->wb, &filepages, &headroom, &dtc->dirty,

				    &writeback);

		if (include_writeback)

			dtc->dirty += writeback;

		mdtc_calc_avail(dtc, filepages, headroom);

	}

}



/**

 * __wb_calc_thresh - @wb's share of dirty threshold

 * @dtc: dirty_throttle_context of interest
@@ -899,16 +927,9 @@ unsigned long cgwb_calc_thresh(struct bdi_writeback *wb) 
{

	struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB };

	struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) };

	unsigned long filepages = 0, headroom = 0, writeback = 0;



	gdtc.avail = global_dirtyable_memory();

	gdtc.dirty = global_node_page_state(NR_FILE_DIRTY) +

		     global_node_page_state(NR_WRITEBACK);



	mem_cgroup_wb_stats(wb, &filepages, &headroom,

			    &mdtc.dirty, &writeback);

	mdtc.dirty += writeback;

	mdtc_calc_avail(&mdtc, filepages, headroom);

	domain_dirty_avail(&gdtc, true);

	domain_dirty_avail(&mdtc, true);

	domain_dirty_limits(&mdtc);



	return __wb_calc_thresh(&mdtc, mdtc.thresh);
@@ -1719,9 +1740,8 @@ static int balance_dirty_pages(struct bdi_writeback *wb, 
		unsigned long m_bg_thresh = 0;



		nr_dirty = global_node_page_state(NR_FILE_DIRTY);

		gdtc->avail = global_dirtyable_memory();

		gdtc->dirty = nr_dirty + global_node_page_state(NR_WRITEBACK);



		domain_dirty_avail(gdtc, true);

		domain_dirty_limits(gdtc);



		if (unlikely(strictlimit)) {
@@ -1737,17 +1757,11 @@ static int balance_dirty_pages(struct bdi_writeback *wb, 
		}



		if (mdtc) {

			unsigned long filepages, headroom, writeback;



			/*

			 * If @wb belongs to !root memcg, repeat the same

			 * basic calculations for the memcg domain.

			 */

			mem_cgroup_wb_stats(wb, &filepages, &headroom,

					    &mdtc->dirty, &writeback);

			mdtc->dirty += writeback;

			mdtc_calc_avail(mdtc, filepages, headroom);



			domain_dirty_avail(mdtc, true);

			domain_dirty_limits(mdtc);



			if (unlikely(strictlimit)) {
@@ -2119,14 +2133,8 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb) 
	struct dirty_throttle_control * const mdtc = mdtc_valid(&mdtc_stor) ?

						     &mdtc_stor : NULL;



	/*

	 * Similar to balance_dirty_pages() but ignores pages being written

	 * as we're trying to decide whether to put more under writeback.

	 */

	gdtc->avail = global_dirtyable_memory();

	gdtc->dirty = global_node_page_state(NR_FILE_DIRTY);

	domain_dirty_avail(gdtc, false);

	domain_dirty_limits(gdtc);



	if (gdtc->dirty > gdtc->bg_thresh)

		return true;
@@ -2135,13 +2143,8 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb) 
		return true;



	if (mdtc) {

		unsigned long filepages, headroom, writeback;



		mem_cgroup_wb_stats(wb, &filepages, &headroom, &mdtc->dirty,

				    &writeback);

		mdtc_calc_avail(mdtc, filepages, headroom);

		domain_dirty_avail(mdtc, false);

		domain_dirty_limits(mdtc);	/* ditto, ignore writeback */



		if (mdtc->dirty > mdtc->bg_thresh)

			return true;