[PATCH] Make high and batch sizes of per_cpu_pagelists configurable (8ad4b1fb) · Commits · 戴 / test

Documentation/sysctl/vm.txt

+17 −0

Original line number	Diff line number	Diff line
		@@ -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.

include/linux/mmzone.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -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. */

include/linux/sysctl.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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 */
		};

kernel/sysctl.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -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,

mm/page_alloc.c

+49 −0

Original line number	Diff line number	Diff line
		@@ -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

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