diff options
Diffstat (limited to 'module/zfs/zil.c')
| -rw-r--r-- | module/zfs/zil.c | 67 |
1 files changed, 61 insertions, 6 deletions
diff --git a/module/zfs/zil.c b/module/zfs/zil.c index ff14a98b6..71079c4a3 100644 --- a/module/zfs/zil.c +++ b/module/zfs/zil.c @@ -1424,6 +1424,13 @@ uint64_t zil_block_buckets[] = { }; /* + * Maximum block size used by the ZIL. This is picked up when the ZIL is + * initialized. Otherwise this should not be used directly; see + * zl_max_block_size instead. + */ +int zil_maxblocksize = SPA_OLD_MAXBLOCKSIZE; + +/* * Start a log block write and advance to the next log block. * Calls are serialized. */ @@ -1499,9 +1506,7 @@ zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb) zil_blksz = zilog->zl_cur_used + sizeof (zil_chain_t); for (i = 0; zil_blksz > zil_block_buckets[i]; i++) continue; - zil_blksz = zil_block_buckets[i]; - if (zil_blksz == UINT64_MAX) - zil_blksz = SPA_OLD_MAXBLOCKSIZE; + zil_blksz = MIN(zil_block_buckets[i], zilog->zl_max_block_size); zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz; for (i = 0; i < ZIL_PREV_BLKS; i++) zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]); @@ -1562,13 +1567,47 @@ zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb) return (nlwb); } +/* + * Maximum amount of write data that can be put into single log block. + */ +uint64_t +zil_max_log_data(zilog_t *zilog) +{ + return (zilog->zl_max_block_size - + sizeof (zil_chain_t) - sizeof (lr_write_t)); +} + +/* + * Maximum amount of log space we agree to waste to reduce number of + * WR_NEED_COPY chunks to reduce zl_get_data() overhead (~12%). + */ +static inline uint64_t +zil_max_waste_space(zilog_t *zilog) +{ + return (zil_max_log_data(zilog) / 8); +} + +/* + * Maximum amount of write data for WR_COPIED. For correctness, consumers + * must fall back to WR_NEED_COPY if we can't fit the entire record into one + * maximum sized log block, because each WR_COPIED record must fit in a + * single log block. For space efficiency, we want to fit two records into a + * max-sized log block. + */ +uint64_t +zil_max_copied_data(zilog_t *zilog) +{ + return ((zilog->zl_max_block_size - sizeof (zil_chain_t)) / 2 - + sizeof (lr_write_t)); +} + static lwb_t * zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb) { lr_t *lrcb, *lrc; lr_write_t *lrwb, *lrw; char *lr_buf; - uint64_t dlen, dnow, lwb_sp, reclen, txg; + uint64_t dlen, dnow, lwb_sp, reclen, txg, max_log_data; ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); ASSERT3P(lwb, !=, NULL); @@ -1617,15 +1656,27 @@ cont: * For WR_NEED_COPY optimize layout for minimal number of chunks. */ lwb_sp = lwb->lwb_sz - lwb->lwb_nused; + max_log_data = zil_max_log_data(zilog); if (reclen > lwb_sp || (reclen + dlen > lwb_sp && - lwb_sp < ZIL_MAX_WASTE_SPACE && (dlen % ZIL_MAX_LOG_DATA == 0 || - lwb_sp < reclen + dlen % ZIL_MAX_LOG_DATA))) { + lwb_sp < zil_max_waste_space(zilog) && + (dlen % max_log_data == 0 || + lwb_sp < reclen + dlen % max_log_data))) { lwb = zil_lwb_write_issue(zilog, lwb); if (lwb == NULL) return (NULL); zil_lwb_write_open(zilog, lwb); ASSERT(LWB_EMPTY(lwb)); lwb_sp = lwb->lwb_sz - lwb->lwb_nused; + + /* + * There must be enough space in the new, empty log block to + * hold reclen. For WR_COPIED, we need to fit the whole + * record in one block, and reclen is the header size + the + * data size. For WR_NEED_COPY, we can create multiple + * records, splitting the data into multiple blocks, so we + * only need to fit one word of data per block; in this case + * reclen is just the header size (no data). + */ ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp); } @@ -3124,6 +3175,7 @@ zil_alloc(objset_t *os, zil_header_t *zh_phys) zilog->zl_dirty_max_txg = 0; zilog->zl_last_lwb_opened = NULL; zilog->zl_last_lwb_latency = 0; + zilog->zl_max_block_size = zil_maxblocksize; mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL); mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL); @@ -3637,5 +3689,8 @@ MODULE_PARM_DESC(zil_nocacheflush, "Disable ZIL cache flushes"); module_param(zil_slog_bulk, ulong, 0644); MODULE_PARM_DESC(zil_slog_bulk, "Limit in bytes slog sync writes per commit"); + +module_param(zil_maxblocksize, int, 0644); +MODULE_PARM_DESC(zil_maxblocksize, "Limit in bytes of ZIL log block size"); /* END CSTYLED */ #endif |