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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: akpm@linux-foundation.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 22/46] flex_proportions: Allow N events instead of 1
Date: Tue, 22 Jun 2021 13:15:27 +0100	[thread overview]
Message-ID: <20210622121551.3398730-23-willy@infradead.org> (raw)
In-Reply-To: <20210622121551.3398730-1-willy@infradead.org>

When batching events (such as writing back N pages in a single I/O), it
is better to do one flex_proportion operation instead of N.  There is
only one caller of __fprop_inc_percpu_max(), and it's the one we're
going to change in the next patch, so rename it instead of adding a
compatibility wrapper.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/flex_proportions.h |  9 +++++----
 lib/flex_proportions.c           | 28 +++++++++++++++++++---------
 mm/page-writeback.c              |  4 ++--
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/include/linux/flex_proportions.h b/include/linux/flex_proportions.h
index c12df59d3f5f..3e378b1fb0bc 100644
--- a/include/linux/flex_proportions.h
+++ b/include/linux/flex_proportions.h
@@ -83,9 +83,10 @@ struct fprop_local_percpu {
 
 int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);
 void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
-void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);
-void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,
-			    int max_frac);
+void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl,
+		long nr);
+void __fprop_add_percpu_max(struct fprop_global *p,
+		struct fprop_local_percpu *pl, int max_frac, long nr);
 void fprop_fraction_percpu(struct fprop_global *p,
 	struct fprop_local_percpu *pl, unsigned long *numerator,
 	unsigned long *denominator);
@@ -96,7 +97,7 @@ void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
 	unsigned long flags;
 
 	local_irq_save(flags);
-	__fprop_inc_percpu(p, pl);
+	__fprop_add_percpu(p, pl, 1);
 	local_irq_restore(flags);
 }
 
diff --git a/lib/flex_proportions.c b/lib/flex_proportions.c
index 451543937524..53e7eb1dd76c 100644
--- a/lib/flex_proportions.c
+++ b/lib/flex_proportions.c
@@ -217,11 +217,12 @@ static void fprop_reflect_period_percpu(struct fprop_global *p,
 }
 
 /* Event of type pl happened */
-void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
+void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl,
+		long nr)
 {
 	fprop_reflect_period_percpu(p, pl);
-	percpu_counter_add_batch(&pl->events, 1, PROP_BATCH);
-	percpu_counter_add(&p->events, 1);
+	percpu_counter_add_batch(&pl->events, nr, PROP_BATCH);
+	percpu_counter_add(&p->events, nr);
 }
 
 void fprop_fraction_percpu(struct fprop_global *p,
@@ -253,20 +254,29 @@ void fprop_fraction_percpu(struct fprop_global *p,
 }
 
 /*
- * Like __fprop_inc_percpu() except that event is counted only if the given
+ * Like __fprop_add_percpu() except that event is counted only if the given
  * type has fraction smaller than @max_frac/FPROP_FRAC_BASE
  */
-void __fprop_inc_percpu_max(struct fprop_global *p,
-			    struct fprop_local_percpu *pl, int max_frac)
+void __fprop_add_percpu_max(struct fprop_global *p,
+		struct fprop_local_percpu *pl, int max_frac, long nr)
 {
 	if (unlikely(max_frac < FPROP_FRAC_BASE)) {
 		unsigned long numerator, denominator;
+		s64 tmp;
 
 		fprop_fraction_percpu(p, pl, &numerator, &denominator);
-		if (numerator >
-		    (((u64)denominator) * max_frac) >> FPROP_FRAC_SHIFT)
+		/* Adding 'nr' to fraction exceeds max_frac/FPROP_FRAC_BASE? */
+		tmp = (u64)denominator * max_frac -
+					((u64)numerator << FPROP_FRAC_SHIFT);
+		if (tmp < 0) {
+			/* Maximum fraction already exceeded? */
 			return;
+		} else if (tmp < nr * (FPROP_FRAC_BASE - max_frac)) {
+			/* Add just enough for the fraction to saturate */
+			nr = div_u64(tmp + FPROP_FRAC_BASE - max_frac - 1,
+					FPROP_FRAC_BASE - max_frac);
+		}
 	}
 
-	__fprop_inc_percpu(p, pl);
+	__fprop_add_percpu(p, pl, nr);
 }
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7ad5538f2489..8079d5ef19df 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -571,8 +571,8 @@ static void wb_domain_writeout_inc(struct wb_domain *dom,
 				   struct fprop_local_percpu *completions,
 				   unsigned int max_prop_frac)
 {
-	__fprop_inc_percpu_max(&dom->completions, completions,
-			       max_prop_frac);
+	__fprop_add_percpu_max(&dom->completions, completions,
+			       max_prop_frac, 1);
 	/* First event after period switching was turned off? */
 	if (unlikely(!dom->period_time)) {
 		/*
-- 
2.30.2


  parent reply	other threads:[~2021-06-22 12:36 UTC|newest]

Thread overview: 128+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-22 12:15 [PATCH v2 00/46] Folio-enabling the page cache Matthew Wilcox (Oracle)
2021-06-22 12:15 ` [PATCH v2 01/46] mm: Add folio_to_pfn() Matthew Wilcox (Oracle)
2021-06-23  7:49   ` Christoph Hellwig
2021-06-24 15:12     ` Matthew Wilcox
2021-06-28  6:18       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 02/46] mm: Add folio_rmapping() Matthew Wilcox (Oracle)
2021-06-23  7:56   ` Christoph Hellwig
2021-06-24 15:51     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 03/46] mm: Add kmap_local_folio() Matthew Wilcox (Oracle)
2021-06-23  7:58   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 04/46] mm: Add flush_dcache_folio() Matthew Wilcox (Oracle)
2021-06-22 12:15 ` [PATCH v2 05/46] mm: Add arch_make_folio_accessible() Matthew Wilcox (Oracle)
2021-06-23  8:00   ` Christoph Hellwig
2021-06-24 15:57     ` Matthew Wilcox
2021-06-28  6:21       ` Christoph Hellwig
2021-06-28 14:07         ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 06/46] mm: Add folio_young() and folio_idle() Matthew Wilcox (Oracle)
2021-06-22 12:15 ` [PATCH v2 07/46] mm/workingset: Convert workingset_activation to take a folio Matthew Wilcox (Oracle)
2021-06-23  8:02   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 08/46] mm/swap: Add folio_activate() Matthew Wilcox (Oracle)
2021-06-23  8:04   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 09/46] mm/swap: Add folio_mark_accessed() Matthew Wilcox (Oracle)
2021-06-23  8:07   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 10/46] mm/rmap: Add folio_mkclean() Matthew Wilcox (Oracle)
2021-06-23  8:08   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 11/46] mm/memcg: Remove 'page' parameter to mem_cgroup_charge_statistics() Matthew Wilcox (Oracle)
2021-06-23  8:09   ` Christoph Hellwig
2021-06-25  7:58   ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 12/46] mm/memcg: Use the node id in mem_cgroup_update_tree() Matthew Wilcox (Oracle)
2021-06-23  8:12   ` Christoph Hellwig
2021-06-24 16:19     ` Matthew Wilcox
2021-06-25  8:05       ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 13/46] mm/memcg: Convert commit_charge() to take a folio Matthew Wilcox (Oracle)
2021-06-23  8:13   ` Christoph Hellwig
2021-06-25  8:11   ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 14/46] mm/memcg: Add folio_charge_cgroup() Matthew Wilcox (Oracle)
2021-06-23  8:15   ` Christoph Hellwig
2021-06-24 16:42     ` Matthew Wilcox
2021-06-25  8:22       ` Michal Hocko
2021-06-25 11:34         ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 15/46] mm/memcg: Add folio_uncharge_cgroup() Matthew Wilcox (Oracle)
2021-06-23  8:16   ` Christoph Hellwig
2021-06-25  8:25   ` Michal Hocko
2021-06-25 11:21     ` Matthew Wilcox
2021-06-25 13:21       ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 16/46] mm/memcg: Add folio_migrate_cgroup() Matthew Wilcox (Oracle)
2021-06-23  8:19   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 17/46] mm/memcg: Convert mem_cgroup_track_foreign_dirty_slowpath() to folio Matthew Wilcox (Oracle)
2021-06-23  8:21   ` Christoph Hellwig
2021-06-24 17:37     ` Matthew Wilcox
2021-06-28  6:24       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 18/46] mm/migrate: Add folio_migrate_mapping() Matthew Wilcox (Oracle)
2021-06-23  8:22   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 19/46] mm/migrate: Add folio_migrate_flags() Matthew Wilcox (Oracle)
2021-06-23  8:28   ` Christoph Hellwig
2021-06-24 17:55     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 20/46] mm/migrate: Add folio_migrate_copy() Matthew Wilcox (Oracle)
2021-06-23  8:35   ` Christoph Hellwig
2021-06-24 18:02     ` Matthew Wilcox
2021-06-28  6:26       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 21/46] mm/writeback: Rename __add_wb_stat() to wb_stat_mod() Matthew Wilcox (Oracle)
2021-06-23  8:37   ` Christoph Hellwig
2021-06-22 12:15 ` Matthew Wilcox (Oracle) [this message]
2021-06-23  8:41   ` [PATCH v2 22/46] flex_proportions: Allow N events instead of 1 Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 23/46] mm/writeback: Change __wb_writeout_inc() to __wb_writeout_add() Matthew Wilcox (Oracle)
2021-06-23  8:45   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 24/46] mm/writeback: Add __folio_end_writeback() Matthew Wilcox (Oracle)
2021-06-23  9:15   ` Christoph Hellwig
2021-06-24 18:20     ` Matthew Wilcox
2021-06-28  6:33       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 25/46] mm/writeback: Add folio_start_writeback() Matthew Wilcox (Oracle)
2021-06-23  9:18   ` Christoph Hellwig
2021-06-24 18:33     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 26/46] mm/writeback: Add folio_mark_dirty() Matthew Wilcox (Oracle)
2021-06-23  9:21   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 27/46] mm/writeback: Add __folio_mark_dirty() Matthew Wilcox (Oracle)
2021-06-23  9:27   ` Christoph Hellwig
2021-06-24 18:37     ` Matthew Wilcox
2021-06-28  6:03       ` Christoph Hellwig
2021-06-28 15:43         ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 28/46] mm/writeback: Add filemap_dirty_folio() Matthew Wilcox (Oracle)
2021-06-23  9:32   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 29/46] mm/writeback: Add folio_account_cleaned() Matthew Wilcox (Oracle)
2021-06-23  9:36   ` Christoph Hellwig
2021-06-24 20:06     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 30/46] mm/writeback: Add folio_cancel_dirty() Matthew Wilcox (Oracle)
2021-06-23  9:39   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 31/46] mm/writeback: Add folio_clear_dirty_for_io() Matthew Wilcox (Oracle)
2021-06-23  9:43   ` Christoph Hellwig
2021-06-24 20:09     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 32/46] mm/writeback: Add folio_account_redirty() Matthew Wilcox (Oracle)
2021-06-23  9:44   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 33/46] mm/writeback: Add folio_redirty_for_writepage() Matthew Wilcox (Oracle)
2021-06-23  9:45   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 34/46] mm/filemap: Add i_blocks_per_folio() Matthew Wilcox (Oracle)
2021-06-23  9:46   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 35/46] mm/filemap: Add folio_mkwrite_check_truncate() Matthew Wilcox (Oracle)
2021-06-23  9:47   ` Christoph Hellwig
2021-06-23 13:19     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 36/46] mm/filemap: Add readahead_folio() Matthew Wilcox (Oracle)
2021-06-23  9:50   ` Christoph Hellwig
2021-06-24 23:46     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 37/46] mm/workingset: Convert workingset_refault() to take a folio Matthew Wilcox (Oracle)
2021-06-23  9:52   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 38/46] mm: Add folio_evictable() Matthew Wilcox (Oracle)
2021-06-23  9:54   ` Christoph Hellwig
2021-06-24 23:50     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 39/46] mm/lru: Convert __pagevec_lru_add_fn to take a folio Matthew Wilcox (Oracle)
2021-06-23  9:55   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 40/46] mm/lru: Add folio_add_lru() Matthew Wilcox (Oracle)
2021-06-23  9:56   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 41/46] mm/page_alloc: Add folio allocation functions Matthew Wilcox (Oracle)
2021-06-23  9:58   ` Christoph Hellwig
2021-06-25  1:06     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 42/46] mm/filemap: Add filemap_alloc_folio Matthew Wilcox (Oracle)
2021-06-23  9:59   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 43/46] mm/filemap: Add filemap_add_folio Matthew Wilcox (Oracle)
2021-06-23 11:30   ` Christoph Hellwig
2021-06-25  1:57     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 44/46] mm/filemap: Convert mapping_get_entry to return a folio Matthew Wilcox (Oracle)
2021-06-23 11:32   ` Christoph Hellwig
2021-06-25  3:29     ` Matthew Wilcox
2021-06-28  6:07       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 45/46] mm/filemap: Add filemap_get_folio Matthew Wilcox (Oracle)
2021-06-23 11:39   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 46/46] mm/filemap: Add FGP_STABLE Matthew Wilcox (Oracle)
2021-06-23 11:43   ` Christoph Hellwig
2021-06-23 12:15     ` Matthew Wilcox

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