This patch consolidates existing parameters to shrink_slab() to
a new shrink_control struct. This is needed later to pass the same
struct to shrinkers.
changelog v2..v1:
1. define a new struct shrink_control and only pass some values down
to the shrinker instead of the scan_control.
Signed-off-by: Ying Han <yinghan@xxxxxxxxxx>
---
fs/drop_caches.c | 6 +++++-
include/linux/mm.h | 13 +++++++++++--
mm/vmscan.c | 30 ++++++++++++++++++++++--------
3 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 816f88e..c671290 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -36,9 +36,13 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
static void drop_slab(void)
{
int nr_objects;
+ struct shrink_control shrink = {
+ .gfp_mask = GFP_KERNEL,
+ .nr_scanned = 1000,
+ };
do {
- nr_objects = shrink_slab(1000, GFP_KERNEL, 1000);
+ nr_objects = shrink_slab(&shrink, 1000);
} while (nr_objects > 10);
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0716517..7a2f657 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1131,6 +1131,15 @@ static inline void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
#endif
/*
+ * This struct is used to pass information from page reclaim to the shrinkers.
+ * We consolidate the values for easier extention later.
+ */
+struct shrink_control {
+ unsigned long nr_scanned;
+ gfp_t gfp_mask;
+};
+
+/*
* A callback you can register to apply pressure to ageable caches.
*
* 'shrink' is passed a count 'nr_to_scan' and a 'gfpmask'. It should
@@ -1601,8 +1610,8 @@ int in_gate_area_no_task(unsigned long addr);
int drop_caches_sysctl_handler(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
-unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
- unsigned long lru_pages);
+unsigned long shrink_slab(struct shrink_control *shrink,
+ unsigned long lru_pages);
#ifndef CONFIG_MMU
#define randomize_va_space 0
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 060e4c1..40edf73 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -220,11 +220,13 @@ EXPORT_SYMBOL(unregister_shrinker);
*
* Returns the number of slab objects which we shrunk.
*/
-unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
- unsigned long lru_pages)
+unsigned long shrink_slab(struct shrink_control *shrink,
+ unsigned long lru_pages)
{
struct shrinker *shrinker;
unsigned long ret = 0;
+ unsigned long scanned = shrink->nr_scanned;
+ gfp_t gfp_mask = shrink->gfp_mask;
if (scanned == 0)
scanned = SWAP_CLUSTER_MAX;
@@ -2032,7 +2034,8 @@ static bool all_unreclaimable(struct zonelist *zonelist,
* else, the number of pages reclaimed
*/
static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
- struct scan_control *sc)
+ struct scan_control *sc,
+ struct shrink_control *shrink)
{
int priority;
unsigned long total_scanned = 0;
@@ -2066,7 +2069,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
lru_pages += zone_reclaimable_pages(zone);
}
- shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages);
+ shrink->nr_scanned = sc->nr_scanned;
+ shrink_slab(shrink, lru_pages);
if (reclaim_state) {
sc->nr_reclaimed += reclaim_state->reclaimed_slab;
reclaim_state->reclaimed_slab = 0;
@@ -2130,12 +2134,15 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
.mem_cgroup = NULL,
.nodemask = nodemask,
};
+ struct shrink_control shrink = {
+ .gfp_mask = sc.gfp_mask,
+ };
trace_mm_vmscan_direct_reclaim_begin(order,
sc.may_writepage,
gfp_mask);
- nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+ nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
trace_mm_vmscan_direct_reclaim_end(nr_reclaimed);
@@ -2333,6 +2340,9 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
.order = order,
.mem_cgroup = NULL,
};
+ struct shrink_control shrink = {
+ .gfp_mask = sc.gfp_mask,
+ };
loop_again:
total_scanned = 0;
sc.nr_reclaimed = 0;
@@ -2432,8 +2442,8 @@ loop_again:
end_zone, 0))
shrink_zone(priority, zone, &sc);
reclaim_state->reclaimed_slab = 0;
- nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
- lru_pages);
+ shrink.nr_scanned = sc.nr_scanned;
+ nr_slab = shrink_slab(&shrink, lru_pages);
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
total_scanned += sc.nr_scanned;
@@ -2969,6 +2979,9 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
.swappiness = vm_swappiness,
.order = order,
};
+ struct shrink_control shrink = {
+ .gfp_mask = sc.gfp_mask,
+ };
unsigned long nr_slab_pages0, nr_slab_pages1;
cond_resched();
@@ -2995,6 +3008,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
}
nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
+ shrink.nr_scanned = sc.nr_scanned;
if (nr_slab_pages0 > zone->min_slab_pages) {
/*
* shrink_slab() does not currently allow us to determine how
@@ -3010,7 +3024,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
unsigned long lru_pages = zone_reclaimable_pages(zone);
/* No reclaimable slab or very low memory pressure */
- if (!shrink_slab(sc.nr_scanned, gfp_mask, lru_pages))
+ if (!shrink_slab(&shrink, lru_pages))
break;
/* Freed enough memory */
--
1.7.3.1
--
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