5509a5d27b
There is plenty of anecdotal evidence and a load of blog posts suggesting that using "drop_caches" periodically keeps your system running in "tip top shape". Perhaps adding some kernel documentation will increase the amount of accurate data on its use. If we are not shrinking caches effectively, then we have real bugs. Using drop_caches will simply mask the bugs and make them harder to find, but certainly does not fix them, nor is it an appropriate "workaround" to limit the size of the caches. On the contrary, there have been bug reports on issues that turned out to be misguided use of cache dropping. Dropping caches is a very drastic and disruptive operation that is good for debugging and running tests, but if it creates bug reports from production use, kernel developers should be aware of its use. Add a bit more documentation about it, a syslog message to track down abusers, and vmstat drop counters to help analyze problem reports. [akpm@linux-foundation.org: checkpatch fixes] [hannes@cmpxchg.org: add runtime suppression control] Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
87 lines
2.3 KiB
C
87 lines
2.3 KiB
C
#ifndef VM_EVENT_ITEM_H_INCLUDED
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#define VM_EVENT_ITEM_H_INCLUDED
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#ifdef CONFIG_ZONE_DMA
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#define DMA_ZONE(xx) xx##_DMA,
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#else
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#define DMA_ZONE(xx)
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#endif
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#ifdef CONFIG_ZONE_DMA32
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#define DMA32_ZONE(xx) xx##_DMA32,
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#else
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#define DMA32_ZONE(xx)
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#endif
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#ifdef CONFIG_HIGHMEM
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#define HIGHMEM_ZONE(xx) , xx##_HIGH
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#else
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#define HIGHMEM_ZONE(xx)
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#endif
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#define FOR_ALL_ZONES(xx) DMA_ZONE(xx) DMA32_ZONE(xx) xx##_NORMAL HIGHMEM_ZONE(xx) , xx##_MOVABLE
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enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
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FOR_ALL_ZONES(PGALLOC),
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PGFREE, PGACTIVATE, PGDEACTIVATE,
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PGFAULT, PGMAJFAULT,
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FOR_ALL_ZONES(PGREFILL),
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FOR_ALL_ZONES(PGSTEAL_KSWAPD),
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FOR_ALL_ZONES(PGSTEAL_DIRECT),
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FOR_ALL_ZONES(PGSCAN_KSWAPD),
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FOR_ALL_ZONES(PGSCAN_DIRECT),
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PGSCAN_DIRECT_THROTTLE,
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#ifdef CONFIG_NUMA
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PGSCAN_ZONE_RECLAIM_FAILED,
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#endif
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PGINODESTEAL, SLABS_SCANNED, KSWAPD_INODESTEAL,
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KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
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PAGEOUTRUN, ALLOCSTALL, PGROTATED,
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DROP_PAGECACHE, DROP_SLAB,
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#ifdef CONFIG_NUMA_BALANCING
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NUMA_PTE_UPDATES,
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NUMA_HUGE_PTE_UPDATES,
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NUMA_HINT_FAULTS,
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NUMA_HINT_FAULTS_LOCAL,
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NUMA_PAGE_MIGRATE,
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#endif
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#ifdef CONFIG_MIGRATION
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PGMIGRATE_SUCCESS, PGMIGRATE_FAIL,
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#endif
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#ifdef CONFIG_COMPACTION
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COMPACTMIGRATE_SCANNED, COMPACTFREE_SCANNED,
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COMPACTISOLATED,
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COMPACTSTALL, COMPACTFAIL, COMPACTSUCCESS,
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#endif
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#ifdef CONFIG_HUGETLB_PAGE
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HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
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#endif
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UNEVICTABLE_PGCULLED, /* culled to noreclaim list */
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UNEVICTABLE_PGSCANNED, /* scanned for reclaimability */
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UNEVICTABLE_PGRESCUED, /* rescued from noreclaim list */
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UNEVICTABLE_PGMLOCKED,
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UNEVICTABLE_PGMUNLOCKED,
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UNEVICTABLE_PGCLEARED, /* on COW, page truncate */
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UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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THP_FAULT_ALLOC,
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THP_FAULT_FALLBACK,
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THP_COLLAPSE_ALLOC,
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THP_COLLAPSE_ALLOC_FAILED,
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THP_SPLIT,
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THP_ZERO_PAGE_ALLOC,
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THP_ZERO_PAGE_ALLOC_FAILED,
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#endif
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#ifdef CONFIG_DEBUG_TLBFLUSH
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#ifdef CONFIG_SMP
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NR_TLB_REMOTE_FLUSH, /* cpu tried to flush others' tlbs */
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NR_TLB_REMOTE_FLUSH_RECEIVED,/* cpu received ipi for flush */
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#endif /* CONFIG_SMP */
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NR_TLB_LOCAL_FLUSH_ALL,
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NR_TLB_LOCAL_FLUSH_ONE,
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#endif /* CONFIG_DEBUG_TLBFLUSH */
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NR_VM_EVENT_ITEMS
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};
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#endif /* VM_EVENT_ITEM_H_INCLUDED */
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