From: Nitin Gupta <nigupta@xxxxxxxxxx> Subject: 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. Link: http://lkml.kernel.org/r/20200618010319.13159-1-nigupta@xxxxxxxxxx Signed-off-by: Nitin Gupta <nigupta@xxxxxxxxxx> Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Iurii Zaikin <yzaikin@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/compaction.h | 4 ++-- kernel/sysctl.c | 2 +- mm/compaction.c | 18 +++++++++--------- mm/vmstat.c | 2 +- 4 files changed, 13 insertions(+), 13 deletions(-) --- a/include/linux/compaction.h~mm-use-unsigned-types-for-fragmentation-score +++ a/include/linux/compaction.h @@ -85,13 +85,13 @@ static inline unsigned long compact_gap( #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, --- a/kernel/sysctl.c~mm-use-unsigned-types-for-fragmentation-score +++ a/kernel/sysctl.c @@ -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, --- a/mm/compaction.c~mm-use-unsigned-types-for-fragmentation-score +++ a/mm/compaction.c @@ -53,7 +53,7 @@ static inline void count_compact_events( /* * 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 * 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(stru * 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_d 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 --- a/mm/vmstat.c~mm-use-unsigned-types-for-fragmentation-score +++ a/mm/vmstat.c @@ -1101,7 +1101,7 @@ static int __fragmentation_index(unsigne * 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; _
