summaryrefslogtreecommitdiffstats
path: root/module/zfs/dbuf_stats.c
Commit message (Collapse)AuthorAgeFilesLines
* Fix dbuf_stats_hash_table_data raceChunwei Chen2016-09-091-2/+0
| | | | | | | | | Dropping DBUF_HASH_MUTEX when walking the hash list is unsafe. The dbuf can be freed at any time. Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #4846
* Illumos 5497 - lock contention on arcs_mtxPrakash Surya2015-06-111-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reviewed by: George Wilson <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Richard Elling <[email protected]> Approved by: Dan McDonald <[email protected]> Porting notes and other significant code changes: The illumos 5368 patch (ARC should cache more metadata), which was never picked up by ZoL, is mostly reverted by this patch. Since ZoL relies on the kernel asynchronously calling the shrinker to actually reap memory, the shrinker wakes up arc_reclaim_waiters_cv every time it runs. The arc_adapt_thread() function no longer calls arc_do_user_evicts() since the newly-added arc_user_evicts_thread() calls it periodically. Notable conflicting ZoL commits which conflicted with this patch or whose effects are either duplicated or un-done by this patch: 302f753 - Integrate ARC more tightly with Linux 39e055c - Adjust arc_p based on "bytes" in arc_shrink f521ce1 - Allow "arc_p" to drop to zero or grow to "arc_c" 77765b5 - Remove "arc_meta_used" from arc_adjust calculation 94520ca - Prune metadata from ghost lists in arc_adjust_meta Trace support for multilist_insert() and multilist_remove() has been added and produces the following output: fio-12498 [077] .... 112936.448324: zfs_multilist__insert: ml { offset 240 numsublists 80 sublistidx 63 } fio-12498 [077] .... 112936.448347: zfs_multilist__remove: ml { offset 240 numsublists 80 sublistidx 29 } The following arcstats have been removed: recycle_miss - Used by arcstat.py and arc_summary.py, both of which have been updated appropriately. l2_writes_hdr_miss The following arcstats have been added: evict_not_enough - Number of times arc_evict_state() was unable to evict enough buffers to reach its target amount. evict_l2_skip - Number of times arc_evict_hdr() skipped eviction because it was being written to the l2arc. l2_writes_lock_retry - Replaces l2_writes_hdr_miss. Number of times l2arc_write_done() failed to acquire hash_lock (and re-tries). arc_meta_min - Shows the value of the zfs_arc_meta_min module parameter (see below). The "index" column of the "dbuf" kstat has been removed since it doesn't have a direct analog in the new multilist scheme. Additional multilist- related stats could be added in the future but would likely require extensions to the mulilist API. The following module parameters have been added: zfs_arc_evict_batch_limit - Number of ARC headers to free per sub-list before moving on to the next sub-list. zfs_arc_meta_min - Enforce a floor on the amount of metadata in the ARC. zfs_arc_num_sublists_per_state - Number of multilist sub-lists per ARC state. zfs_arc_overflow_shift - Controls amount by which the ARC must exceed the target size to be considered "overflowing". Ported-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]
* Skip evicting dbufs when walking the dbuf hashBrian Behlendorf2015-02-061-3/+5
| | | | | | | | | | When a dbuf is in the DB_EVICTING state it may no longer be on the dn_dbufs list. In which case it's unsafe to call DB_DNODE_ENTER. Therefore, any dbuf which is found in this safe must be skipped. Signed-off-by: Brian Behlendorf <[email protected]> Closes #2553 Closes #2495
* Spurious ENOMEM returns when reading dbufs kstatTim Chase2015-02-041-2/+6
| | | | | | | | | | | | | Commit 7b2d78a046aa4695d434478a439a9438521d73af fixed some improper uses of snprintf(), however, in __dbuf_stats_hash_table_data() the return value of snprintf is propagated to the caller. This caused spurious ENOMEM errors when reading the dbufs kstat. This commit causes the actual number of characters written to be returned. Signed-off-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #3072
* Fix improper null-byte termination handlingNed Bass2014-11-171-4/+2
| | | | | | | | | | | | | | | | | | | | | | | Fix a few cases where null-byte termination of strings was done unnecessarily or incorrectly. - The snprintf() function always produces a null-byte terminated string for non-negative return values, so it is not necessary to write out a null-byte as a separate step. - Also, it is unsafe to use the return value of snprintf() as an offset for placing a null-byte, because if the output was truncated the return value is the number of bytes that _would_ have been written had enough space been available. Therefore the return value may index beyond the array boundaries. - Finally, snprintf() accounts for the null-byte when limiting its output size, so there is no need to pass it a size parameter that is one less than the buffer size. Signed-off-by: Ned Bass <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #2875
* cstyle: Resolve C style issuesMichael Kjorling2013-12-181-7/+7
| | | | | | | | | | | | | | | | | | The vast majority of these changes are in Linux specific code. They are the result of not having an automated style checker to validate the code when it was originally written. Others were caused when the common code was slightly adjusted for Linux. This patch contains no functional changes. It only refreshes the code to conform to style guide. Everyone submitting patches for inclusion upstream should now run 'make checkstyle' and resolve any warning prior to opening a pull request. The automated builders have been updated to fail a build if when 'make checkstyle' detects an issue. Signed-off-by: Brian Behlendorf <[email protected]> Closes #1821
* Add visibility in to cached dbufsBrian Behlendorf2013-10-251-0/+230
Currently there is no mechanism to inspect which dbufs are being cached by the system. There are some coarse counters in arcstats by they only give a rough idea of what's being cached. This patch aims to improve the current situation by adding a new dbufs kstat. When read this new kstat will walk all cached dbufs linked in to the dbuf_hash. For each dbuf it will dump detailed information about the buffer. It will also dump additional information about the referenced arc buffer and its related dnode. This provides a more complete view in to exactly what is being cached. With this generic infrastructure in place utilities can be written to post-process the data to understand exactly how the caching is working. For example, the data could be processed to show a list of all cached dnodes and how much space they're consuming. Or a similar list could be generated based on dnode type. Many other ways to interpret the data exist based on what kinds of questions you're trying to answer. Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Prakash Surya <[email protected]>