Commit d34c0a75 authored by Nitin Gupta's avatar Nitin Gupta Committed by Linus Torvalds
Browse files

mm: use unsigned types for fragmentation score 



Proactive compaction uses per-node/zone "fragmentation score" which is
always in range [0, 100], so use unsigned type of these scores as well as
for related constants.

Signed-off-by: default avatarNitin Gupta <nigupta@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarBaoquan He <bhe@redhat.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200618010319.13159-1-nigupta@nvidia.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 25788738

include/linux/compaction.h

+2 −2
Original line number Diff line number Diff line
@@ -85,13 +85,13 @@ static inline unsigned long compact_gap(unsigned int order) 


#ifdef CONFIG_COMPACTION

extern int sysctl_compact_memory;

extern int sysctl_compaction_proactiveness;

extern unsigned int sysctl_compaction_proactiveness;

extern int sysctl_compaction_handler(struct ctl_table *table, int write,

			void *buffer, size_t *length, loff_t *ppos);

extern int sysctl_extfrag_threshold;

extern int sysctl_compact_unevictable_allowed;



extern int extfrag_for_order(struct zone *zone, unsigned int order);

extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order);

extern int fragmentation_index(struct zone *zone, unsigned int order);

extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,

		unsigned int order, unsigned int alloc_flags,

kernel/sysctl.c

+1 −1
Original line number Diff line number Diff line
@@ -2854,7 +2854,7 @@ static struct ctl_table vm_table[] = { 
	{

		.procname	= "compaction_proactiveness",

		.data		= &sysctl_compaction_proactiveness,

		.maxlen		= sizeof(int),

		.maxlen		= sizeof(sysctl_compaction_proactiveness),

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= SYSCTL_ZERO,

mm/compaction.c

+9 −9
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ static inline void count_compact_events(enum vm_event_item item, long delta) 
/*

 * Fragmentation score check interval for proactive compaction purposes.

 */

static const int HPAGE_FRAG_CHECK_INTERVAL_MSEC = 500;

static const unsigned int HPAGE_FRAG_CHECK_INTERVAL_MSEC = 500;



/*

 * Page order with-respect-to which proactive compaction
@@ -1890,7 +1890,7 @@ static bool kswapd_is_running(pg_data_t *pgdat) 
 * ZONE_DMA32. For smaller zones, the score value remains close to zero,

 * and thus never exceeds the high threshold for proactive compaction.

 */

static int fragmentation_score_zone(struct zone *zone)

static unsigned int fragmentation_score_zone(struct zone *zone)

{

	unsigned long score;
@@ -1906,9 +1906,9 @@ static int fragmentation_score_zone(struct zone *zone) 
 * the node's score falls below the low threshold, or one of the back-off

 * conditions is met.

 */

static int fragmentation_score_node(pg_data_t *pgdat)

static unsigned int fragmentation_score_node(pg_data_t *pgdat)

{

	unsigned long score = 0;

	unsigned int score = 0;

	int zoneid;



	for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
@@ -1921,17 +1921,17 @@ static int fragmentation_score_node(pg_data_t *pgdat) 
	return score;

}



static int fragmentation_score_wmark(pg_data_t *pgdat, bool low)

static unsigned int fragmentation_score_wmark(pg_data_t *pgdat, bool low)

{

	int wmark_low;

	unsigned int wmark_low;



	/*

	 * Cap the low watermak to avoid excessive compaction

	 * activity in case a user sets the proactivess tunable

	 * close to 100 (maximum).

	 */

	wmark_low = max(100 - sysctl_compaction_proactiveness, 5);

	return low ? wmark_low : min(wmark_low + 10, 100);

	wmark_low = max(100U - sysctl_compaction_proactiveness, 5U);

	return low ? wmark_low : min(wmark_low + 10, 100U);

}



static bool should_proactive_compact_node(pg_data_t *pgdat)
@@ -2615,7 +2615,7 @@ int sysctl_compact_memory; 
 * aggressively the kernel should compact memory in the

 * background. It takes values in the range [0, 100].

 */

int __read_mostly sysctl_compaction_proactiveness = 20;

unsigned int __read_mostly sysctl_compaction_proactiveness = 20;



/*

 * This is the entry point for compacting all nodes via

mm/vmstat.c

+1 −1
Original line number Diff line number Diff line
@@ -1101,7 +1101,7 @@ static int __fragmentation_index(unsigned int order, struct contig_page_info *in 
 * It is defined as the percentage of pages found in blocks of size

 * less than 1 << order. It returns values in range [0, 100].

 */

int extfrag_for_order(struct zone *zone, unsigned int order)

unsigned int extfrag_for_order(struct zone *zone, unsigned int order)

{

	struct contig_page_info info;