diff options
| -rw-r--r-- | Documentation/sysctl/vm.txt | 17 | ||||
| -rw-r--r-- | include/linux/mmzone.h | 2 | ||||
| -rw-r--r-- | include/linux/sysctl.h | 1 | ||||
| -rw-r--r-- | kernel/sysctl.c | 12 | ||||
| -rw-r--r-- | mm/page_alloc.c | 49 |
5 files changed, 81 insertions, 0 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 89ba1a42a17d..6910c0136f8d 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -103,3 +103,20 @@ This is used to force the Linux VM to keep a minimum number of kilobytes free. The VM uses this number to compute a pages_min value for each lowmem zone in the system. Each lowmem zone gets a number of reserved free pages based proportionally on its size. + +============================================================== + +percpu_pagelist_fraction + +This is the fraction of pages at most (high mark pcp->high) in each zone that +are allocated for each per cpu page list. The min value for this is 8. It +means that we don't allow more than 1/8th of pages in each zone to be +allocated in any single per_cpu_pagelist. This entry only changes the value +of hot per cpu pagelists. User can specify a number like 100 to allocate +1/100th of each zone to each per cpu page list. + +The batch value of each per cpu pagelist is also updated as a result. It is +set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) + +The initial value is zero. Kernel does not use this value at boot time to set +the high water marks for each per cpu page list. diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c34f4a2c62f8..2a89c132ba9c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -437,6 +437,8 @@ int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *, extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *); +int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file *, + void __user *, size_t *, loff_t *); #include <linux/topology.h> /* Returns the number of the current Node. */ diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 4cd267fe87ec..7f472127b7b5 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -181,6 +181,7 @@ enum VM_LEGACY_VA_LAYOUT=27, /* legacy/compatibility virtual address space layout */ VM_SWAP_TOKEN_TIMEOUT=28, /* default time for token time out */ VM_DROP_PAGECACHE=29, /* int: nuke lots of pagecache */ + VM_PERCPU_PAGELIST_FRACTION=30,/* int: fraction of pages in each percpu_pagelist */ }; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 8dcf6fd5b0f9..03b0598f2369 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -69,6 +69,7 @@ extern int printk_ratelimit_jiffies; extern int printk_ratelimit_burst; extern int pid_max_min, pid_max_max; extern int sysctl_drop_caches; +extern int percpu_pagelist_fraction; #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) int unknown_nmi_panic; @@ -79,6 +80,7 @@ extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *, /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */ static int maxolduid = 65535; static int minolduid; +static int min_percpu_pagelist_fract = 8; static int ngroups_max = NGROUPS_MAX; @@ -794,6 +796,16 @@ static ctl_table vm_table[] = { .strategy = &sysctl_intvec, .extra1 = &zero, }, + { + .ctl_name = VM_PERCPU_PAGELIST_FRACTION, + .procname = "percpu_pagelist_fraction", + .data = &percpu_pagelist_fraction, + .maxlen = sizeof(percpu_pagelist_fraction), + .mode = 0644, + .proc_handler = &percpu_pagelist_fraction_sysctl_handler, + .strategy = &sysctl_intvec, + .extra1 = &min_percpu_pagelist_fract, + }, #ifdef CONFIG_MMU { .ctl_name = VM_MAX_MAP_COUNT, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5eeeadd9f66a..2c46f697e8ff 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -53,6 +53,7 @@ struct pglist_data *pgdat_list __read_mostly; unsigned long totalram_pages __read_mostly; unsigned long totalhigh_pages __read_mostly; long nr_swap_pages; +int percpu_pagelist_fraction; static void fastcall free_hot_cold_page(struct page *page, int cold); @@ -1831,6 +1832,24 @@ inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch) INIT_LIST_HEAD(&pcp->list); } +/* + * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist + * to the value high for the pageset p. + */ + +static void setup_pagelist_highmark(struct per_cpu_pageset *p, + unsigned long high) +{ + struct per_cpu_pages *pcp; + + pcp = &p->pcp[0]; /* hot list */ + pcp->high = high; + pcp->batch = max(1UL, high/4); + if ((high/4) > (PAGE_SHIFT * 8)) + pcp->batch = PAGE_SHIFT * 8; +} + + #ifdef CONFIG_NUMA /* * Boot pageset table. One per cpu which is going to be used for all @@ -1868,6 +1887,10 @@ static int __devinit process_zones(int cpu) goto bad; setup_pageset(zone->pageset[cpu], zone_batchsize(zone)); + + if (percpu_pagelist_fraction) + setup_pagelist_highmark(zone_pcp(zone, cpu), + (zone->present_pages / percpu_pagelist_fraction)); } return 0; @@ -2567,6 +2590,32 @@ int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write, return 0; } +/* + * percpu_pagelist_fraction - changes the pcp->high for each zone on each + * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist + * can have before it gets flushed back to buddy allocator. + */ + +int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write, + struct file *file, void __user *buffer, size_t *length, loff_t *ppos) +{ + struct zone *zone; + unsigned int cpu; + int ret; + + ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos); + if (!write || (ret == -EINVAL)) + return ret; + for_each_zone(zone) { + for_each_online_cpu(cpu) { + unsigned long high; + high = zone->present_pages / percpu_pagelist_fraction; + setup_pagelist_highmark(zone_pcp(zone, cpu), high); + } + } + return 0; +} + __initdata int hashdist = HASHDIST_DEFAULT; #ifdef CONFIG_NUMA |