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62695a84eb
On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
45 lines
1.3 KiB
C
45 lines
1.3 KiB
C
#ifndef _LINUX_MIGRATE_H
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#define _LINUX_MIGRATE_H
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#include <linux/mm.h>
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#include <linux/mempolicy.h>
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typedef struct page *new_page_t(struct page *, unsigned long private, int **);
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#ifdef CONFIG_MIGRATION
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extern int putback_lru_pages(struct list_head *l);
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extern int migrate_page(struct address_space *,
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struct page *, struct page *);
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extern int migrate_pages(struct list_head *l, new_page_t x, unsigned long);
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extern int fail_migrate_page(struct address_space *,
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struct page *, struct page *);
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extern int migrate_prep(void);
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extern int migrate_vmas(struct mm_struct *mm,
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const nodemask_t *from, const nodemask_t *to,
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unsigned long flags);
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#else
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static inline int putback_lru_pages(struct list_head *l) { return 0; }
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static inline int migrate_pages(struct list_head *l, new_page_t x,
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unsigned long private) { return -ENOSYS; }
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static inline int migrate_pages_to(struct list_head *pagelist,
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struct vm_area_struct *vma, int dest) { return 0; }
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static inline int migrate_prep(void) { return -ENOSYS; }
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static inline int migrate_vmas(struct mm_struct *mm,
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const nodemask_t *from, const nodemask_t *to,
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unsigned long flags)
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{
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return -ENOSYS;
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}
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/* Possible settings for the migrate_page() method in address_operations */
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#define migrate_page NULL
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#define fail_migrate_page NULL
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#endif /* CONFIG_MIGRATION */
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#endif /* _LINUX_MIGRATE_H */
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