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3741 zfs needs better comments
Submitted by:   Will Andrews <willa@spectralogic.com>
Submitted by:   Justin Gibbs <justing@spectralogic.com>
Submitted by:   Alan Somers <alans@spectralogic.com>
Reviewed by:    Matthew Ahrens <mahrens@delphix.com>

*** 252,262 **** --- 252,273 ---- kstat_named_t arcstat_mru_ghost_hits; kstat_named_t arcstat_mfu_hits; kstat_named_t arcstat_mfu_ghost_hits; kstat_named_t arcstat_deleted; kstat_named_t arcstat_recycle_miss; + /* + * Number of buffers that could not be evicted because the hash lock + * was held by another thread. The lock may not necessarily be held + * by something using the same buffer, since hash locks are shared + * by multiple buffers. + */ kstat_named_t arcstat_mutex_miss; + /* + * Number of buffers skipped because they have I/O in progress, are + * indrect prefetch buffers that have not lived long enough, or are + * not from the spa we're trying to evict from. + */ kstat_named_t arcstat_evict_skip; kstat_named_t arcstat_evict_l2_cached; kstat_named_t arcstat_evict_l2_eligible; kstat_named_t arcstat_evict_l2_ineligible; kstat_named_t arcstat_hash_elements;
*** 2951,2960 **** --- 2962,2975 ---- vd = NULL; } mutex_exit(hash_lock); + /* + * At this point, we have a level 1 cache miss. Try again in + * L2ARC if possible. + */ ASSERT3U(hdr->b_size, ==, size); DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, uint64_t, size, zbookmark_t *, zb); ARCSTAT_BUMP(arcstat_misses); ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH),
*** 3141,3152 **** kmem_cache_free(buf_cache, buf); return (1); } /* ! * Release this buffer from the cache. This must be done ! * after a read and prior to modifying the buffer contents. * If the buffer has more than one reference, we must make * a new hdr for the buffer. */ void arc_release(arc_buf_t *buf, void *tag) --- 3156,3167 ---- kmem_cache_free(buf_cache, buf); return (1); } /* ! * Release this buffer from the cache, making it an anonymous buffer. This ! * must be done after a read and prior to modifying the buffer contents. * If the buffer has more than one reference, we must make * a new hdr for the buffer. */ void arc_release(arc_buf_t *buf, void *tag)