X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=blobdiff_plain;f=module%2Fzfs%2Farc.c;h=f1f972b86ddea02861d2b3d8035d3ec70d3023c4;hb=c409e4647f221ab724a0bd10c480ac95447203c3;hp=3a4573027ad144a0ac6e854643d6a7a3945190e8;hpb=691f6ac4c2858d64afc2a0dc1bd2b8c041d68502;p=zfs.git diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 3a45730..f1f972b 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -180,6 +180,7 @@ unsigned long zfs_arc_meta_limit = 0; int zfs_arc_grow_retry = 0; int zfs_arc_shrink_shift = 0; int zfs_arc_p_min_shift = 0; +int zfs_arc_reduce_dnlc_percent = 0; /* * Note that buffers can be in one of 6 states: @@ -282,6 +283,14 @@ typedef struct arc_stats { kstat_named_t arcstat_l2_size; kstat_named_t arcstat_l2_hdr_size; kstat_named_t arcstat_memory_throttle_count; + kstat_named_t arcstat_memory_direct_count; + kstat_named_t arcstat_memory_indirect_count; + kstat_named_t arcstat_no_grow; + kstat_named_t arcstat_tempreserve; + kstat_named_t arcstat_loaned_bytes; + kstat_named_t arcstat_meta_used; + kstat_named_t arcstat_meta_limit; + kstat_named_t arcstat_meta_max; } arc_stats_t; static arc_stats_t arc_stats = { @@ -337,7 +346,15 @@ static arc_stats_t arc_stats = { { "l2_io_error", KSTAT_DATA_UINT64 }, { "l2_size", KSTAT_DATA_UINT64 }, { "l2_hdr_size", KSTAT_DATA_UINT64 }, - { "memory_throttle_count", KSTAT_DATA_UINT64 } + { "memory_throttle_count", KSTAT_DATA_UINT64 }, + { "memory_direct_count", KSTAT_DATA_UINT64 }, + { "memory_indirect_count", KSTAT_DATA_UINT64 }, + { "arc_no_grow", KSTAT_DATA_UINT64 }, + { "arc_tempreserve", KSTAT_DATA_UINT64 }, + { "arc_loaned_bytes", KSTAT_DATA_UINT64 }, + { "arc_meta_used", KSTAT_DATA_UINT64 }, + { "arc_meta_limit", KSTAT_DATA_UINT64 }, + { "arc_meta_max", KSTAT_DATA_UINT64 }, }; #define ARCSTAT(stat) (arc_stats.stat.value.ui64) @@ -399,13 +416,12 @@ static arc_state_t *arc_l2c_only; #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ - -static int arc_no_grow; /* Don't try to grow cache size */ -static uint64_t arc_tempreserve; -static uint64_t arc_loaned_bytes; -static uint64_t arc_meta_used; -static uint64_t arc_meta_limit; -static uint64_t arc_meta_max = 0; +#define arc_no_grow ARCSTAT(arcstat_no_grow) +#define arc_tempreserve ARCSTAT(arcstat_tempreserve) +#define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes) +#define arc_meta_used ARCSTAT(arcstat_meta_used) +#define arc_meta_limit ARCSTAT(arcstat_meta_limit) +#define arc_meta_max ARCSTAT(arcstat_meta_max) typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; @@ -2069,14 +2085,16 @@ arc_kmem_reap_now(arc_reclaim_strategy_t strat) kmem_cache_t *prev_data_cache = NULL; extern kmem_cache_t *zio_buf_cache[]; extern kmem_cache_t *zio_data_buf_cache[]; - #ifdef _KERNEL - if (arc_meta_used >= arc_meta_limit) { + int retry = 0; + + while ((arc_meta_used >= arc_meta_limit) && (retry < 10)) { /* * We are exceeding our meta-data cache limit. * Purge some DNLC entries to release holds on meta-data. */ dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent); + retry++; } #if defined(__i386) /* @@ -2142,6 +2160,10 @@ arc_reclaim_thread(void) arc_no_grow = FALSE; } + /* Keep meta data usage within limits */ + if (arc_meta_used >= arc_meta_limit) + arc_kmem_reap_now(ARC_RECLAIM_CONS); + arc_adjust(); if (arc_eviction_list != NULL) @@ -2160,6 +2182,51 @@ arc_reclaim_thread(void) thread_exit(); } +#ifdef _KERNEL +/* + * Under Linux the arc shrinker may be called for synchronous (direct) + * reclaim, or asynchronous (indirect) reclaim. When called by kswapd + * for indirect reclaim we take a conservative approach and just reap + * free slabs from the ARC caches. If this proves to be insufficient + * direct reclaim will be trigger. In direct reclaim a more aggressive + * strategy is used, data is evicted from the ARC and free slabs reaped. + */ +SPL_SHRINKER_CALLBACK_PROTO(arc_shrinker_func, cb, nr_to_scan, gfp_mask) +{ + arc_reclaim_strategy_t strategy; + int arc_reclaim; + + /* Not allowed to perform filesystem reclaim */ + if (!(gfp_mask & __GFP_FS)) + return (-1); + + /* Return number of reclaimable pages based on arc_shrink_shift */ + arc_reclaim = btop((arc_size - arc_c_min)) >> arc_shrink_shift; + if (nr_to_scan == 0) + return (arc_reclaim); + + /* Reclaim in progress */ + if (mutex_tryenter(&arc_reclaim_thr_lock) == 0) + return (-1); + + if (current_is_kswapd()) { + strategy = ARC_RECLAIM_CONS; + ARCSTAT_INCR(arcstat_memory_indirect_count, 1); + } else { + strategy = ARC_RECLAIM_AGGR; + ARCSTAT_INCR(arcstat_memory_direct_count, 1); + } + + arc_kmem_reap_now(strategy); + arc_reclaim = btop((arc_size - arc_c_min)) >> arc_shrink_shift; + mutex_exit(&arc_reclaim_thr_lock); + + return (arc_reclaim); +} + +SPL_SHRINKER_DECLARE(arc_shrinker, arc_shrinker_func, DEFAULT_SEEKS); +#endif /* _KERNEL */ + /* * Adapt arc info given the number of bytes we are trying to add and * the state that we are comming from. This function is only called @@ -3474,6 +3541,12 @@ arc_init(void) * need to limit the cache to 1/8 of VM size. */ arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); + /* + * Register a shrinker to support synchronous (direct) memory + * reclaim from the arc. This is done to prevent kswapd from + * swapping out pages when it is preferable to shrink the arc. + */ + spl_register_shrinker(&arc_shrinker); #endif /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ @@ -3499,6 +3572,7 @@ arc_init(void) /* limit meta-data to 1/4 of the arc capacity */ arc_meta_limit = arc_c_max / 4; + arc_meta_max = 0; /* Allow the tunable to override if it is reasonable */ if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) @@ -3516,6 +3590,9 @@ arc_init(void) if (zfs_arc_p_min_shift > 0) arc_p_min_shift = zfs_arc_p_min_shift; + if (zfs_arc_reduce_dnlc_percent > 0) + arc_reduce_dnlc_percent = zfs_arc_reduce_dnlc_percent; + /* if kmem_flags are set, lets try to use less memory */ if (kmem_debugging()) arc_c = arc_c / 2; @@ -3590,6 +3667,10 @@ void arc_fini(void) { mutex_enter(&arc_reclaim_thr_lock); +#ifdef _KERNEL + spl_unregister_shrinker(&arc_shrinker); +#endif /* _KERNEL */ + arc_thread_exit = 1; while (arc_thread_exit != 0) cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); @@ -4686,12 +4767,25 @@ EXPORT_SYMBOL(arc_read); EXPORT_SYMBOL(arc_buf_remove_ref); EXPORT_SYMBOL(arc_getbuf_func); -module_param(zfs_arc_min, ulong, 0644); -MODULE_PARM_DESC(zfs_arc_min, "Minimum arc size"); +module_param(zfs_arc_min, ulong, 0444); +MODULE_PARM_DESC(zfs_arc_min, "Min arc size"); -module_param(zfs_arc_max, ulong, 0644); -MODULE_PARM_DESC(zfs_arc_max, "Maximum arc size"); +module_param(zfs_arc_max, ulong, 0444); +MODULE_PARM_DESC(zfs_arc_max, "Max arc size"); -module_param(zfs_arc_meta_limit, ulong, 0644); +module_param(zfs_arc_meta_limit, ulong, 0444); MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size"); + +module_param(zfs_arc_reduce_dnlc_percent, int, 0444); +MODULE_PARM_DESC(zfs_arc_reduce_dnlc_percent, "Meta reclaim percentage"); + +module_param(zfs_arc_grow_retry, int, 0444); +MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size"); + +module_param(zfs_arc_shrink_shift, int, 0444); +MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); + +module_param(zfs_arc_p_min_shift, int, 0444); +MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p"); + #endif