diff options
Diffstat (limited to 'module')
| -rw-r--r-- | module/zfs/ddt_zap.c | 14 | ||||
| -rw-r--r-- | module/zfs/dmu.c | 16 | ||||
| -rw-r--r-- | module/zfs/zap.c | 56 | ||||
| -rw-r--r-- | module/zfs/zap_micro.c | 31 |
4 files changed, 110 insertions, 7 deletions
diff --git a/module/zfs/ddt_zap.c b/module/zfs/ddt_zap.c index 77c0784cc..3489d31d9 100644 --- a/module/zfs/ddt_zap.c +++ b/module/zfs/ddt_zap.c @@ -21,6 +21,7 @@ /* * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2018 by Delphix. All rights reserved. */ #include <sys/zfs_context.h> @@ -117,7 +118,18 @@ ddt_zap_walk(objset_t *os, uint64_t object, ddt_entry_t *dde, uint64_t *walk) zap_attribute_t za; int error; - zap_cursor_init_serialized(&zc, os, object, *walk); + if (*walk == 0) { + /* + * We don't want to prefetch the entire ZAP object, because + * it can be enormous. Also the primary use of DDT iteration + * is for scrubbing, in which case we will be issuing many + * scrub I/Os for each ZAP block that we read in, so + * reading the ZAP is unlikely to be the bottleneck. + */ + zap_cursor_init_noprefetch(&zc, os, object); + } else { + zap_cursor_init_serialized(&zc, os, object, *walk); + } if ((error = zap_cursor_retrieve(&zc, &za)) == 0) { uchar_t cbuf[sizeof (dde->dde_phys) + 1]; uint64_t csize = za.za_num_integers; diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c index 2d6740576..b4131d917 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -81,6 +81,13 @@ int zfs_dmu_offset_next_sync = 0; */ int zfs_object_remap_one_indirect_delay_ms = 0; +/* + * Limit the amount we can prefetch with one call to this amount. This + * helps to limit the amount of memory that can be used by prefetching. + * Larger objects should be prefetched a bit at a time. + */ +int dmu_prefetch_max = 8 * SPA_MAXBLOCKSIZE; + const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = { {DMU_BSWAP_UINT8, TRUE, FALSE, FALSE, "unallocated" }, {DMU_BSWAP_ZAP, TRUE, TRUE, FALSE, "object directory" }, @@ -668,6 +675,11 @@ dmu_prefetch(objset_t *os, uint64_t object, int64_t level, uint64_t offset, } /* + * See comment before the definition of dmu_prefetch_max. + */ + len = MIN(len, dmu_prefetch_max); + + /* * XXX - Note, if the dnode for the requested object is not * already cached, we will do a *synchronous* read in the * dnode_hold() call. The same is true for any indirects. @@ -2629,6 +2641,10 @@ module_param(zfs_dmu_offset_next_sync, int, 0644); MODULE_PARM_DESC(zfs_dmu_offset_next_sync, "Enable forcing txg sync to find holes"); +module_param(dmu_prefetch_max, int, 0644); +MODULE_PARM_DESC(dmu_prefetch_max, + "Limit one prefetch call to this size"); + /* END CSTYLED */ #endif diff --git a/module/zfs/zap.c b/module/zfs/zap.c index 6d8c49804..30f62ac43 100644 --- a/module/zfs/zap.c +++ b/module/zfs/zap.c @@ -20,7 +20,7 @@ */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2012, 2016 by Delphix. All rights reserved. + * Copyright (c) 2012, 2018 by Delphix. All rights reserved. * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. */ @@ -49,6 +49,36 @@ #include <sys/zap_impl.h> #include <sys/zap_leaf.h> +/* + * If zap_iterate_prefetch is set, we will prefetch the entire ZAP object + * (all leaf blocks) when we start iterating over it. + * + * For zap_cursor_init(), the callers all intend to iterate through all the + * entries. There are a few cases where an error (typically i/o error) could + * cause it to bail out early. + * + * For zap_cursor_init_serialized(), there are callers that do the iteration + * outside of ZFS. Typically they would iterate over everything, but we + * don't have control of that. E.g. zfs_ioc_snapshot_list_next(), + * zcp_snapshots_iter(), and other iterators over things in the MOS - these + * are called by /sbin/zfs and channel programs. The other example is + * zfs_readdir() which iterates over directory entries for the getdents() + * syscall. /sbin/ls iterates to the end (unless it receives a signal), but + * userland doesn't have to. + * + * Given that the ZAP entries aren't returned in a specific order, the only + * legitimate use cases for partial iteration would be: + * + * 1. Pagination: e.g. you only want to display 100 entries at a time, so you + * get the first 100 and then wait for the user to hit "next page", which + * they may never do). + * + * 2. You want to know if there are more than X entries, without relying on + * the zfs-specific implementation of the directory's st_size (which is + * the number of entries). + */ +int zap_iterate_prefetch = B_TRUE; + int fzap_default_block_shift = 14; /* 16k blocksize */ extern inline zap_phys_t *zap_f_phys(zap_t *zap); @@ -1189,6 +1219,21 @@ fzap_cursor_retrieve(zap_t *zap, zap_cursor_t *zc, zap_attribute_t *za) /* retrieve the next entry at or after zc_hash/zc_cd */ /* if no entry, return ENOENT */ + /* + * If we are reading from the beginning, we're almost certain to + * iterate over the entire ZAP object. If there are multiple leaf + * blocks (freeblk > 2), prefetch the whole object (up to + * dmu_prefetch_max bytes), so that we read the leaf blocks + * concurrently. (Unless noprefetch was requested via + * zap_cursor_init_noprefetch()). + */ + if (zc->zc_hash == 0 && zap_iterate_prefetch && + zc->zc_prefetch && zap_f_phys(zap)->zap_freeblk > 2) { + dmu_prefetch(zc->zc_objset, zc->zc_zapobj, 0, 0, + zap_f_phys(zap)->zap_freeblk << FZAP_BLOCK_SHIFT(zap), + ZIO_PRIORITY_ASYNC_READ); + } + if (zc->zc_leaf && (ZAP_HASH_IDX(zc->zc_hash, zap_leaf_phys(zc->zc_leaf)->l_hdr.lh_prefix_len) != @@ -1333,3 +1378,12 @@ fzap_get_stats(zap_t *zap, zap_stats_t *zs) } } } + +#if defined(_KERNEL) +/* BEGIN CSTYLED */ +module_param(zap_iterate_prefetch, int, 0644); +MODULE_PARM_DESC(zap_iterate_prefetch, + "When iterating ZAP object, prefetch it"); + +/* END CSTYLED */ +#endif diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c index fa369f797..467812ff6 100644 --- a/module/zfs/zap_micro.c +++ b/module/zfs/zap_micro.c @@ -21,7 +21,7 @@ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2011, 2017 by Delphix. All rights reserved. + * Copyright (c) 2011, 2018 by Delphix. All rights reserved. * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. * Copyright 2017 Nexenta Systems, Inc. */ @@ -1472,9 +1472,9 @@ zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key, * Routines for iterating over the attributes. */ -void -zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *os, uint64_t zapobj, - uint64_t serialized) +static void +zap_cursor_init_impl(zap_cursor_t *zc, objset_t *os, uint64_t zapobj, + uint64_t serialized, boolean_t prefetch) { zc->zc_objset = os; zc->zc_zap = NULL; @@ -1483,12 +1483,33 @@ zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *os, uint64_t zapobj, zc->zc_serialized = serialized; zc->zc_hash = 0; zc->zc_cd = 0; + zc->zc_prefetch = prefetch; +} +void +zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *os, uint64_t zapobj, + uint64_t serialized) +{ + zap_cursor_init_impl(zc, os, zapobj, serialized, B_TRUE); } +/* + * Initialize a cursor at the beginning of the ZAP object. The entire + * ZAP object will be prefetched. + */ void zap_cursor_init(zap_cursor_t *zc, objset_t *os, uint64_t zapobj) { - zap_cursor_init_serialized(zc, os, zapobj, 0); + zap_cursor_init_impl(zc, os, zapobj, 0, B_TRUE); +} + +/* + * Initialize a cursor at the beginning, but request that we not prefetch + * the entire ZAP object. + */ +void +zap_cursor_init_noprefetch(zap_cursor_t *zc, objset_t *os, uint64_t zapobj) +{ + zap_cursor_init_impl(zc, os, zapobj, 0, B_FALSE); } void |