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path: root/fs/ext4/extents_status.c
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* ext4: fix setting of referenced bit in ext4_es_lookup_extent()Jan Kara2016-03-091-2/+2
| | | | | | | | | | We were setting referenced bit on the extent structure we return from ext4_es_lookup_extent() which is just a private structure on stack. Thus setting had no effect. Set the bit in the structure in the status tree instead. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: move procfs registration code to fs/ext4/sysfs.cTheodore Ts'o2015-09-231-58/+2
| | | | | | | | | This allows us to refactor the procfs code, which saves a bit of compiled space. More importantly it isolates most of the procfs support code into a single file, so it's easier to #ifdef it out if the proc file system has been disabled. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: fix data corruption caused by unwritten and delayed extentsLukas Czerner2015-05-021-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently it is possible to lose whole file system block worth of data when we hit the specific interaction with unwritten and delayed extents in status extent tree. The problem is that when we insert delayed extent into extent status tree the only way to get rid of it is when we write out delayed buffer. However there is a limitation in the extent status tree implementation so that when inserting unwritten extent should there be even a single delayed block the whole unwritten extent would be marked as delayed. At this point, there is no way to get rid of the delayed extents, because there are no delayed buffers to write out. So when a we write into said unwritten extent we will convert it to written, but it still remains delayed. When we try to write into that block later ext4_da_map_blocks() will set the buffer new and delayed and map it to invalid block which causes the rest of the block to be zeroed loosing already written data. For now we can fix this by simply not allowing to set delayed status on written extent in the extent status tree. Also add WARN_ON() to make sure that we notice if this happens in the future. This problem can be easily reproduced by running the following xfs_io. xfs_io -f -c "pwrite -S 0xaa 4096 2048" \ -c "falloc 0 131072" \ -c "pwrite -S 0xbb 65536 2048" \ -c "fsync" /mnt/test/fff echo 3 > /proc/sys/vm/drop_caches xfs_io -c "pwrite -S 0xdd 67584 2048" /mnt/test/fff This can be theoretically also reproduced by at random by running fsx, but it's not very reliable, though on machines with bigger page size (like ppc) this can be seen more often (especially xfstest generic/127) Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
* ext4: remove unused header filesSheng Yong2015-04-021-2/+0
| | | | | | | | Remove unused header files and header files which are included in ext4.h. Signed-off-by: Sheng Yong <shengyong1@huawei.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: introduce aging to extent status treeJan Kara2014-11-251-5/+17
| | | | | | | | | | Introduce a simple aging to extent status tree. Each extent has a REFERENCED bit which gets set when the extent is used. Shrinker then skips entries with referenced bit set and clears the bit. Thus frequently used extents have higher chances of staying in memory. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: cleanup flag definitions for extent status treeJan Kara2014-11-251-0/+2
| | | | | | | | | | | Currently flags for extent status tree are defined twice, once shifted and once without a being shifted. Consolidate these definitions into one place and make some computations automatic to make adding flags less error prone. Compiler should be clever enough to figure out these are constants and generate the same code. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: limit number of scanned extents in status tree shrinkerJan Kara2014-11-251-32/+59
| | | | | | | | | | | | | | | | | | | | | | Currently we scan extent status trees of inodes until we reclaim nr_to_scan extents. This can however require a lot of scanning when there are lots of delayed extents (as those cannot be reclaimed). Change shrinker to work as shrinkers are supposed to and *scan* only nr_to_scan extents regardless of how many extents did we actually reclaim. We however need to be careful and avoid scanning each status tree from the beginning - that could lead to a situation where we would not be able to reclaim anything at all when first nr_to_scan extents in the tree are always unreclaimable. We remember with each inode offset where we stopped scanning and continue from there when we next come across the inode. Note that we also need to update places calling __es_shrink() manually to pass reasonable nr_to_scan to have a chance of reclaiming anything and not just 1. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: move handling of list of shrinkable inodes into extent status codeJan Kara2014-11-251-4/+6
| | | | | | | | | | | | | Currently callers adding extents to extent status tree were responsible for adding the inode to the list of inodes with freeable extents. This is error prone and puts list handling in unnecessarily many places. Just add inode to the list automatically when the first non-delay extent is added to the tree and remove inode from the list when the last non-delay extent is removed. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: change LRU to round-robin in extent status tree shrinkerZheng Liu2014-11-251-127/+97
| | | | | | | | | | | | | | | | In this commit we discard the lru algorithm for inodes with extent status tree because it takes significant effort to maintain a lru list in extent status tree shrinker and the shrinker can take a long time to scan this lru list in order to reclaim some objects. We replace the lru ordering with a simple round-robin. After that we never need to keep a lru list. That means that the list needn't be sorted if the shrinker can not reclaim any objects in the first round. Cc: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* Merge tag 'ext4_for_linus' of ↵Linus Torvalds2014-10-201-18/+182
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "A large number of cleanups and bug fixes, with some (minor) journal optimizations" [ This got sent to me before -rc1, but was stuck in my spam folder. - Linus ] * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (67 commits) ext4: check s_chksum_driver when looking for bg csum presence ext4: move error report out of atomic context in ext4_init_block_bitmap() ext4: Replace open coded mdata csum feature to helper function ext4: delete useless comments about ext4_move_extents ext4: fix reservation overflow in ext4_da_write_begin ext4: add ext4_iget_normal() which is to be used for dir tree lookups ext4: don't orphan or truncate the boot loader inode ext4: grab missed write_count for EXT4_IOC_SWAP_BOOT ext4: optimize block allocation on grow indepth ext4: get rid of code duplication ext4: fix over-defensive complaint after journal abort ext4: fix return value of ext4_do_update_inode ext4: fix mmap data corruption when blocksize < pagesize vfs: fix data corruption when blocksize < pagesize for mmaped data ext4: fold ext4_nojournal_sops into ext4_sops ext4: support freezing ext2 (nojournal) file systems ext4: fold ext4_sync_fs_nojournal() into ext4_sync_fs() ext4: don't check quota format when there are no quota files jbd2: simplify calling convention around __jbd2_journal_clean_checkpoint_list jbd2: avoid pointless scanning of checkpoint lists ...
| * ext4: track extent status tree shrinker delay staticticsZheng Liu2014-09-011-10/+176
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds some statictics in extent status tree shrinker. The purpose to add these is that we want to collect more details when we encounter a stall caused by extent status tree shrinker. Here we count the following statictics: stats: the number of all objects on all extent status trees the number of reclaimable objects on lru list cache hits/misses the last sorted interval the number of inodes on lru list average: scan time for shrinking some objects the number of shrunk objects maximum: the inode that has max nr. of objects on lru list the maximum scan time for shrinking some objects The output looks like below: $ cat /proc/fs/ext4/sda1/es_shrinker_info stats: 28228 objects 6341 reclaimable objects 5281/631 cache hits/misses 586 ms last sorted interval 250 inodes on lru list average: 153 us scan time 128 shrunk objects maximum: 255 inode (255 objects, 198 reclaimable) 125723 us max scan time If the lru list has never been sorted, the following line will not be printed: 586ms last sorted interval If there is an empty lru list, the following lines also will not be printed: 250 inodes on lru list ... maximum: 255 inode (255 objects, 198 reclaimable) 0 us max scan time Meanwhile in this commit a new trace point is defined to print some details in __ext4_es_shrink(). Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: improve extents status tree trace pointZheng Liu2014-09-011-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit improves the trace point of extents status tree. We rename trace_ext4_es_shrink_enter in ext4_es_count() because it is also used in ext4_es_scan() and we can not identify them from the result. Further this commit fixes a variable name in trace point in order to keep consistency with others. Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: rename ext4_ext_find_extent() to ext4_find_extent()Theodore Ts'o2014-09-011-1/+1
| | | | | | | | | | | | Make the function name less redundant. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: allow a NULL argument to ext4_ext_drop_refs()Theodore Ts'o2014-09-011-4/+2
|/ | | | | | | | Teach ext4_ext_drop_refs() to accept a NULL argument, much like kfree(). This allows us to drop a lot of checks to make sure path is non-NULL before calling ext4_ext_drop_refs(). Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: fix a potential deadlock in __ext4_es_shrink()Theodore Ts'o2014-07-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes the following lockdep complaint: [ INFO: possible circular locking dependency detected ] 3.16.0-rc2-mm1+ #7 Tainted: G O ------------------------------------------------------- kworker/u24:0/4356 is trying to acquire lock: (&(&sbi->s_es_lru_lock)->rlock){+.+.-.}, at: [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0 but task is already holding lock: (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180 which lock already depends on the new lock. Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->i_es_lock); lock(&(&sbi->s_es_lru_lock)->rlock); lock(&ei->i_es_lock); lock(&(&sbi->s_es_lru_lock)->rlock); *** DEADLOCK *** 6 locks held by kworker/u24:0/4356: #0: ("writeback"){.+.+.+}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560 #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560 #2: (&type->s_umount_key#22){++++++}, at: [<ffffffff811a9c74>] grab_super_passive+0x44/0x90 #3: (jbd2_handle){+.+...}, at: [<ffffffff812979f9>] start_this_handle+0x189/0x5f0 #4: (&ei->i_data_sem){++++..}, at: [<ffffffff81247062>] ext4_map_blocks+0x132/0x550 #5: (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180 stack backtrace: CPU: 0 PID: 4356 Comm: kworker/u24:0 Tainted: G O 3.16.0-rc2-mm1+ #7 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: writeback bdi_writeback_workfn (flush-253:0) ffffffff8213dce0 ffff880014b07538 ffffffff815df0bb 0000000000000007 ffffffff8213e040 ffff880014b07588 ffffffff815db3dd ffff880014b07568 ffff880014b07610 ffff88003b868930 ffff88003b868908 ffff88003b868930 Call Trace: [<ffffffff815df0bb>] dump_stack+0x4e/0x68 [<ffffffff815db3dd>] print_circular_bug+0x1fb/0x20c [<ffffffff810a7a3e>] __lock_acquire+0x163e/0x1d00 [<ffffffff815e89dc>] ? retint_restore_args+0xe/0xe [<ffffffff815ddc7b>] ? __slab_alloc+0x4a8/0x4ce [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0 [<ffffffff810a8707>] lock_acquire+0x87/0x120 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0 [<ffffffff8128592d>] ? ext4_es_free_extent+0x5d/0x70 [<ffffffff815e6f09>] _raw_spin_lock+0x39/0x50 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0 [<ffffffff8119760b>] ? kmem_cache_alloc+0x18b/0x1a0 [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0 [<ffffffff812869b8>] ext4_es_insert_extent+0xc8/0x180 [<ffffffff812470f4>] ext4_map_blocks+0x1c4/0x550 [<ffffffff8124c4c4>] ext4_writepages+0x6d4/0xd00 ... Reported-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reported-by: Minchan Kim <minchan@kernel.org> Cc: stable@vger.kernel.org Cc: Zheng Liu <gnehzuil.liu@gmail.com>
* ext4: use EXT_MAX_BLOCKS in ext4_es_can_be_merged()Lukas Czerner2014-05-121-1/+7
| | | | | | | | | | | | In ext4_es_can_be_merged() when checking whether we can merge two extents we should use EXT_MAX_BLOCKS instead of defining it manually. Also if it is really the case we should notify userspace because clearly there is a bug in extent status tree implementation since this should never happen. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: rename uninitialized extents to unwrittenLukas Czerner2014-04-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Currently in ext4 there is quite a mess when it comes to naming unwritten extents. Sometimes we call it uninitialized and sometimes we refer to it as unwritten. The right name for the extent which has been allocated but does not contain any written data is _unwritten_. Other file systems are using this name consistently, even the buffer head state refers to it as unwritten. We need to fix this confusion in ext4. This commit changes every reference to an uninitialized extent (meaning allocated but unwritten) to unwritten extent. This includes comments, function names and variable names. It even covers abbreviation of the word uninitialized (such as uninit) and some misspellings. This commit does not change any of the code paths at all. This has been confirmed by comparing md5sums of the assembly code of each object file after all the function names were stripped from it. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: fix 64-bit number truncation warningChen Gang2014-04-071-1/+1
| | | | | | | | | | | | | | '0x7FDEADBEEF' will be truncated to 32-bit number under unicore32. Need append 'ULL' for it. The related warning (with allmodconfig under unicore32): CC [M] fs/ext4/extents_status.o fs/ext4/extents_status.c: In function "__es_remove_extent": fs/ext4/extents_status.c:813: warning: integer constant is too large for "long" type Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: silence warnings in extent status tree debugging codeEric Whitney2014-02-201-7/+7
| | | | | | | | | Adjust the conversion specifications in a few optionally compiled debug messages to match the return type of ext4_es_status(). Also, make a couple of minor grammatical message edits while we're at it. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: add ext4_es_store_pblock_status()Theodore Ts'o2014-02-191-8/+6
| | | | | | | | | | | | | | Avoid false positives by static code analysis tools such as sparse and coverity caused by the fact that we set the physical block, and then the status in the extent_status structure. It is also more efficient to set both of these values at once. Addresses-Coverity-Id: #989077 Addresses-Coverity-Id: #989078 Addresses-Coverity-Id: #1080722 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* fs: convert fs shrinkers to new scan/count APIDave Chinner2013-09-101-9/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the filesystem shrinkers to use the new API, and standardise some of the behaviours of the shrinkers at the same time. For example, nr_to_scan means the number of objects to scan, not the number of objects to free. I refactored the CIFS idmap shrinker a little - it really needs to be broken up into a shrinker per tree and keep an item count with the tree root so that we don't need to walk the tree every time the shrinker needs to count the number of objects in the tree (i.e. all the time under memory pressure). [glommer@openvz.org: fixes for ext4, ubifs, nfs, cifs and glock. Fixes are needed mainly due to new code merged in the tree] [assorted fixes folded in] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ext4: isolate ext4_extents.h fileZheng Liu2013-08-281-18/+2
| | | | | | | | | | | | | | | | | | | After applied the commit (4a092d73), we have reduced the number of source files that need to #include ext4_extents.h. But we can do better. This commit defines ext4_zeroout_es() in extents.c and move EXT_MAX_BLOCKS into ext4.h in order not to include ext4_extents.h in indirect.c and ioctl.c. Meanwhile we just need to include this file in extent_status.c when ES_AGGRESSIVE_TEST is defined. Otherwise, this commit removes a duplicated declaration in trace/events/ext4.h. After applied this patch, we just need to include ext4_extents.h file in {super,migrate,move_extents,extents}.c, and it is easy for us to define a new extent disk layout. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: add support for extent pre-cachingTheodore Ts'o2013-08-161-21/+51
| | | | | | | | | | | | | | | Add a new fiemap flag which forces the all of the extents in an inode to be cached in the extent_status tree. This is critically important when using AIO to a preallocated file, since if we need to read in blocks from the extent tree, the io_submit(2) system call becomes synchronous, and the AIO is no longer "A", which is bad. In addition, for most files which have an external leaf tree block, the cost of caching the information in the extent status tree will be less than caching the entire 4k block in the buffer cache. So it is generally a win to keep the extent information cached. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: cache all of an extent tree's leaf block upon readingTheodore Ts'o2013-08-161-1/+36
| | | | | | | | | | | When we read in an extent tree leaf block from disk, arrange to have all of its entries cached. In nearly all cases the in-memory representation will be more compact than the on-disk representation in the buffer cache, and it allows us to get the information without having to traverse the extent tree for successive extents. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: use unsigned int for es_status valuesTheodore Ts'o2013-08-161-3/+3
| | | | | | | | | | | Don't use an unsigned long long for the es_status flags; this requires that we pass 64-bit values around which is painful on 32-bit systems. Instead pass the extent status flags around using the low 4 bits of an unsigned int, and shift them into place when we are reading or writing es_pblk. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: make the extent_status code more robust against ENOMEM failuresTheodore Ts'o2013-07-151-12/+39
| | | | | | | | | | | | | | | | | Some callers of ext4_es_remove_extent() and ext4_es_insert_extent() may not be completely robust against ENOMEM failures (or the consequences of reflecting ENOMEM back up to userspace may lead to xfstest or user application failure). To mitigate against this, when trying to insert an entry in the extent status tree, try to shrink the inode's extent status tree before returning ENOMEM. If there are entries which don't record information about extents under delayed allocations, freeing one of them is preferable to returning ENOMEM. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: fix spelling errors and a comment in extent_status treeTheodore Ts'o2013-07-131-12/+10
| | | | | | | | | | | Replace "assertation" with "assertion" in lots and lots of debugging messages. Correct the comment stating when ext4_es_insert_extent() is used. It was no doubt tree at one point, but it is no longer true... Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Zheng Liu <gnehzuil.liu@gmail.com>
* ext4: improve extent cache shrink mechanism to avoid to burn CPU timeZheng Liu2013-07-011-20/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now we maintain an proper in-order LRU list in ext4 to reclaim entries from extent status tree when we are under heavy memory pressure. For keeping this order, a spin lock is used to protect this list. But this lock burns a lot of CPU time. We can use the following steps to trigger it. % cd /dev/shm % dd if=/dev/zero of=ext4-img bs=1M count=2k % mkfs.ext4 ext4-img % mount -t ext4 -o loop ext4-img /mnt % cd /mnt % for ((i=0;i<160;i++)); do truncate -s 64g $i; done % for ((i=0;i<160;i++)); do cp $i /dev/null &; done % perf record -a -g % perf report This commit tries to fix this problem. Now a new member called i_touch_when is added into ext4_inode_info to record the last access time for an inode. Meanwhile we never need to keep a proper in-order LRU list. So this can avoid to burns some CPU time. When we try to reclaim some entries from extent status tree, we use list_sort() to get a proper in-order list. Then we traverse this list to discard some entries. In ext4_sb_info, we use s_es_last_sorted to record the last time of sorting this list. When we traverse the list, we skip the inode that is newer than this time, and move this inode to the tail of LRU list. When the head of the list is newer than s_es_last_sorted, we will sort the LRU list again. In this commit, we break the loop if s_extent_cache_cnt == 0 because that means that all extents in extent status tree have been reclaimed. Meanwhile in this commit, ext4_es_{un}register_shrinker()'s prototype is changed to save a local variable in these functions. Reported-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: fix fio regressionYan, Zheng2013-05-031-5/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We (Linux Kernel Performance project) found a regression introduced by commit: f7fec032aa ext4: track all extent status in extent status tree The commit causes about 20% performance decrease in fio random write test. Profiler shows that rb_next() uses a lot of CPU time. The call stack is: rb_next ext4_es_find_delayed_extent ext4_map_blocks _ext4_get_block ext4_get_block_write __blockdev_direct_IO ext4_direct_IO generic_file_direct_write __generic_file_aio_write ext4_file_write aio_rw_vect_retry aio_run_iocb do_io_submit sys_io_submit system_call_fastpath io_submit td_io_getevents io_u_queued_complete thread_main main __libc_start_main The cause is that ext4_es_find_delayed_extent() doesn't have an upper bound, it keeps searching until a delayed extent is found. When there are a lots of non-delayed entries in the extent state tree, ext4_es_find_delayed_extent() may uses a lot of CPU time. Reported-by: LKP project <lkp@linux.intel.com> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Cc: "Theodore Ts'o" <tytso@mit.edu>
* ext4: update extent status tree after an extent is zeroed outZheng Liu2013-03-101-0/+17
| | | | | | | | | | | | | | | When we try to split an extent, this extent could be zeroed out and mark as initialized. But we don't know this in ext4_map_blocks because it only returns a length of allocated extent. Meanwhile we will mark this extent as uninitialized because we only check m_flags. This commit update extent status tree when we try to split an unwritten extent. We don't need to worry about the status of this extent because we always mark it as initialized. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Dmitry Monakhov <dmonakhov@openvz.org>
* ext4: add self-testing infrastructure to do a sanity checkDmitry Monakhov2013-03-101-0/+175
| | | | | | | | | | | | | | | | | | | | | | | | This commit adds a self-testing infrastructure like extent tree does to do a sanity check for extent status tree. After status tree is as a extent cache, we'd better to make sure that it caches right result. After applied this commit, we will get a lot of messages when we run xfstests as below. ... kernel: ES len assertation failed for inode: 230 retval 1 != map->m_len 3 in ext4_map_blocks (allocation) ... kernel: ES cache assertation failed for inode: 230 es_cached ex [974/2/4781/20] != found ex [974/1/4781/1000] ... kernel: ES insert assertation failed for inode: 635 ex_status [0/45/21388/w] != es_status [44/1/21432/u] ... Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: avoid a potential overflow in ext4_es_can_be_merged()Zheng Liu2013-03-101-5/+15
| | | | | | | | | Check the length of an extent to avoid a potential overflow in ext4_es_can_be_merged(). Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Dmitry Monakhov <dmonakhov@openvz.org>
* ext4: use percpu counter for extent cache countTheodore Ts'o2013-03-021-4/+4
| | | | | | | | | | | Use a percpu counter rather than atomic types for shrinker accounting. There's no need for ultimate accuracy in the shrinker, so this should come a little more cheaply. The percpu struct is somewhat large, but there was a big gap before the cache-aligned s_es_lru_lock anyway, and it fits nicely in there. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: optimize ext4_es_shrink()Theodore Ts'o2013-02-281-26/+13
| | | | | | | | | | | | | | | When the system is under memory pressure, ext4_es_srhink() will get called very often. So optimize returning the number of items in the file system's extent status cache by keeping a per-filesystem count, instead of calculating it each time by scanning all of the inodes in the extent status cache. Also rename the slab used for the extent status cache to be "ext4_extent_status" so it's obviousl the slab in question is created by ext4. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Zheng Liu <gnehzuil.liu@gmail.com>
* ext4: no need to remove extent if len is 0 in ext4_es_remove_extent()Eryu Guan2013-02-221-0/+6
| | | | | | | | | | | | | | | | | | | | | | len is 0 means no extent needs to be removed, so return immediately. Otherwise it could trigger the following BUG_ON() in ext4_es_remove_extent() end = lblk + len - 1; BUG_ON(end < lblk); This could be reproduced by a simple truncate(1) command by an unprivileged user truncate -s $(($((2**32 - 1)) * 4096)) /mnt/ext4/testfile The same is true for __es_insert_extent(). Patched kernel passed xfstests regression test. Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: reclaim extents from extent status treeZheng Liu2013-02-181-0/+156
| | | | | | | | | | | | | | | | | | | | | | | | | | | Although extent status is loaded on-demand, we also need to reclaim extent from the tree when we are under a heavy memory pressure because in some cases fragmented extent tree causes status tree costs too much memory. Here we maintain a lru list in super_block. When the extent status of an inode is accessed and changed, this inode will be move to the tail of the list. The inode will be dropped from this list when it is cleared. In the inode, a counter is added to count the number of cached objects in extent status tree. Here only written/unwritten/hole extent is counted because delayed extent doesn't be reclaimed due to fiemap, bigalloc and seek_data/hole need it. The counter will be increased as a new extent is allocated, and it will be decreased as a extent is freed. In this commit we use normal shrinker framework to reclaim memory from the status tree. ext4_es_reclaim_extents_count() traverses the lru list to count the number of reclaimable extents. ext4_es_shrink() tries to reclaim written/unwritten/hole extents from extent status tree. The inode that has been shrunk is moved to the tail of lru list. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
* ext4: adjust some functions for reclaiming extents from extent status treeZheng Liu2013-02-181-26/+24
| | | | | | | | | This commit changes some interfaces in extent status tree because we need to use inode to count the cached objects in a extent status tree. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
* ext4: lookup block mapping in extent status treeZheng Liu2013-02-181-0/+60
| | | | | | | | | | | | | | | | | | | After tracking all extent status, we already have a extent cache in memory. Every time we want to lookup a block mapping, we can first try to lookup it in extent status tree to avoid a potential disk I/O. A new function called ext4_es_lookup_extent is defined to finish this work. When we try to lookup a block mapping, we always call ext4_map_blocks and/or ext4_da_map_blocks. So in these functions we first try to lookup a block mapping in extent status tree. A new flag EXT4_GET_BLOCKS_NO_PUT_HOLE is used in ext4_da_map_blocks in order not to put a hole into extent status tree because this hole will be converted to delayed extent in the tree immediately. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
* ext4: rename and improbe ext4_es_find_extent()Zheng Liu2013-02-181-20/+20
| | | | | | | | | | | This commit renames ext4_es_find_extent with ext4_es_find_delayed_extent and improve this function. First, we split input and output parameter. Second, this function never return the first block of the next delayed extent after 'es'. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
* ext4: add physical block and status member into extent status treeZheng Liu2013-02-181-12/+55
| | | | | | | | | | | | | | | This commit adds two members in extent_status structure to let it record physical block and extent status. Here es_pblk is used to record both of them because physical block only has 48 bits. So extent status could be stashed into it so that we can save some memory. Now written, unwritten, delayed and hole are defined as status. Due to new member is added into extent status tree, all interfaces need to be adjusted. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
* ext4: refine extent status treeZheng Liu2013-02-181-141/+181
| | | | | | | | | | | | | | | | | | | | | | This commit refines the extent status tree code. 1) A prefix 'es_' is added to to the extent status tree structure members. 2) Refactored es_remove_extent() so that __es_remove_extent() can be used by es_insert_extent() to remove the old extent entry(-ies) before inserting a new one. 3) Rename extent_status_end() to ext4_es_end() 4) ext4_es_can_be_merged() is define to check whether two extents can be merged or not. 5) Update and clarified comments. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
* ext4: add some tracepoints in extent status treeZheng Liu2012-11-081-0/+8
| | | | | | | This patch adds some tracepoints in extent status tree. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: add operations on extent status treeZheng Liu2012-11-081-0/+492
This patch adds operations on a extent status tree. CC: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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