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2014-01-28Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "Assorted stuff; the biggest pile here is Christoph's ACL series. Plus assorted cleanups and fixes all over the place... There will be another pile later this week" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (43 commits) __dentry_path() fixes vfs: Remove second variable named error in __dentry_path vfs: Is mounted should be testing mnt_ns for NULL or error. Fix race when checking i_size on direct i/o read hfsplus: remove can_set_xattr nfsd: use get_acl and ->set_acl fs: remove generic_acl nfs: use generic posix ACL infrastructure for v3 Posix ACLs gfs2: use generic posix ACL infrastructure jfs: use generic posix ACL infrastructure xfs: use generic posix ACL infrastructure reiserfs: use generic posix ACL infrastructure ocfs2: use generic posix ACL infrastructure jffs2: use generic posix ACL infrastructure hfsplus: use generic posix ACL infrastructure f2fs: use generic posix ACL infrastructure ext2/3/4: use generic posix ACL infrastructure btrfs: use generic posix ACL infrastructure fs: make posix_acl_create more useful fs: make posix_acl_chmod more useful ...
2014-01-25f2fs: use generic posix ACL infrastructureChristoph Hellwig
f2fs has some weird mode bit handling, so still using the old chmod code for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jaegeuk Kim <jaegeuk.kim@samsung.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-01-22f2fs: introduce NODE_MAPPING for code consistencyJaegeuk Kim
This patch adds NODE_MAPPING which is similar as META_MAPPING introduced by Gu Zheng. Cc: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-22f2fs: add help function META_MAPPINGGu Zheng
Introduce help function META_MAPPING() to get the cache meta blocks' address space. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-20f2fs: clean checkpatch warningsChris Fries
Fixed a variety of trivial checkpatch warnings. The only delta should be some minor formatting on log strings that were split / too long. Signed-off-by: Chris Fries <cfries@motorola.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-14f2fs: use spinlock rather than mutex for better speedGu Zheng
With the 2 previous changes, all the long time operations are moved out of the protection region, so here we can use spinlock rather than mutex (orphan_inode_mutex) for lower overhead. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-14f2fs: remove the needless parameter of f2fs_wait_on_page_writebackYuan Zhong
"boo sync" parameter is never referenced in f2fs_wait_on_page_writeback. We should remove this parameter. Signed-off-by: Yuan Zhong <yuan.mark.zhong@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-08f2fs: add a sysfs entry to control max_victim_searchJaegeuk Kim
Previously during SSR and GC, the maximum number of retrials to find a victim segment was hard-coded by MAX_VICTIM_SEARCH, 4096 by default. This number makes an effect on IO locality, when SSR mode is activated, which results in performance fluctuation on some low-end devices. If max_victim_search = 4, the victim will be searched like below. ("D" represents a dirty segment, and "*" indicates a selected victim segment.) D1 D2 D3 D4 D5 D6 D7 D8 D9 [ * ] [ * ] [ * ] [ ....] This patch adds a sysfs entry to control the number dynamically through: /sys/fs/f2fs/$dev/max_victim_search Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-08f2fs: improve write performance under frequent fsync callsJaegeuk Kim
When considering a bunch of data writes with very frequent fsync calls, we are able to think the following performance regression. N: Node IO, D: Data IO, IO scheduler: cfq Issue pending IOs D1 D2 D3 D4 D1 D2 D3 D4 N1 D2 D3 D4 N1 N2 N1 D3 D4 N2 D1 --> N1 can be selected by cfq becase of the same priority of N and D. Then D3 and D4 would be delayed, resuling in performance degradation. So, when processing the fsync call, it'd better give higher priority to data IOs than node IOs by assigning WRITE and WRITE_SYNC respectively. This patch improves the random wirte performance with frequent fsync calls by up to 10%. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-06f2fs: add inline_data recovery routineJaegeuk Kim
This patch adds a inline_data recovery routine with the following policy. [prev.] [next] of inline_data flag o o -> recover inline_data o x -> remove inline_data, and then recover data blocks x o -> remove inline_data, and then recover inline_data x x -> recover data blocks Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-06f2fs: add the number of inline_data files to status infoJaegeuk Kim
This patch adds the number of inline_data files into the status information. Note that the number is reset whenever the filesystem is newly mounted. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2014-01-06f2fs: refactor f2fs_convert_inline_dataJaegeuk Kim
Change log from v1: o handle NULL pointer of grab_cache_page_write_begin() pointed by Chao Yu. This patch refactors f2fs_convert_inline_data to check a couple of conditions internally for deciding whether it needs to convert inline_data or not. So, the new f2fs_convert_inline_data initially checks: 1) f2fs_has_inline_data(), and 2) the data size to be changed. If the inode has inline_data but the size to fill is less than MAX_INLINE_DATA, then we don't need to convert the inline_data with data allocation. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-26f2fs: key functions to handle inline dataHuajun Li
Functions to implement inline data read/write, and move inline data to normal data block when file size exceeds inline data limitation. Signed-off-by: Huajun Li <huajun.li@intel.com> Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Weihong Xu <weihong.xu@intel.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-26f2fs: convert max_orphans to a field of f2fs_sb_infoGu Zheng
Previously, we need to calculate the max orphan num when we try to acquire an orphan inode, but it's a stable value since the super block was inited. So converting it to a field of f2fs_sb_info and use it directly when needed seems a better choose. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-26f2fs: introduce F2FS_INODE macro to get f2fs_inodeJaegeuk Kim
This patch introduces F2FS_INODE that returns struct f2fs_inode * from the inode page. By using this macro, we can remove unnecessary casting codes like below. struct f2fs_inode *ri = &F2FS_NODE(inode_page)->i; -> struct f2fs_inode *ri = F2FS_INODE(inode_page); Reviewed-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: update several commentsChao Yu
Update several comments: 1. use f2fs_{un}lock_op install of mutex_{un}lock_op. 2. update comment of get_data_block(). 3. update description of node offset. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: remove the rw_flag domain from f2fs_io_infoGu Zheng
When using the f2fs_io_info in the low level, we still need to merge the rw and rw_flag, so use the rw to hold all the io flags directly, and remove the rw_flag field. ps.It is based on the previous patch: f2fs: move all the bio initialization into __bio_alloc Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: introduce a new direct_IO write pathJaegeuk Kim
Previously, f2fs doesn't support direct IOs with high performance, which throws every write requests via the buffered write path, resulting in highly performance degradation due to memory opeations like copy_from_user. This patch introduces a new direct IO path in which every write requests are processed by generic blockdev_direct_IO() with enhanced get_block function. The get_data_block() in f2fs handles: 1. if original data blocks are allocates, then give them to blockdev. 2. otherwise, a. preallocate requested block addresses b. do not use extent cache for better performance c. give the block addresses to blockdev This policy induces that: - new allocated data are sequentially written to the disk - updated data are randomly written to the disk. - f2fs gives consistency on its file meta, not file data. Reviewed-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: introduce sysfs entry to control in-place-update policyJaegeuk Kim
This patch introduces new sysfs entries for users to control the policy of in-place-updates, namely IPU, in f2fs. Sometimes f2fs suffers from performance degradation due to its out-of-place update policy that produces many additional node block writes. If the storage performance is very dependant on the amount of data writes instead of IO patterns, we'd better drop this out-of-place update policy. This patch suggests 5 polcies and their triggering conditions as follows. [sysfs entry name = ipu_policy] 0: F2FS_IPU_FORCE all the time, 1: F2FS_IPU_SSR if SSR mode is activated, 2: F2FS_IPU_UTIL if FS utilization is over threashold, 3: F2FS_IPU_SSR_UTIL if SSR mode is activated and FS utilization is over threashold, 4: F2FS_IPU_DISABLE disable IPU. (=default option) [sysfs entry name = min_ipu_util] This parameter controls the threshold to trigger in-place-updates. The number indicates percentage of the filesystem utilization, and used by F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies. For more details, see need_inplace_update() in segment.h. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: refactor bio->rw handlingJaegeuk Kim
This patch introduces f2fs_io_info to mitigate the complex parameter list. struct f2fs_io_info { enum page_type type; /* contains DATA/NODE/META/META_FLUSH */ int rw; /* contains R/RS/W/WS */ int rw_flag; /* contains REQ_META/REQ_PRIO */ } 1. f2fs_write_data_pages - DATA - WRITE_SYNC is set when wbc->WB_SYNC_ALL. 2. sync_node_pages - NODE - WRITE_SYNC all the time 3. sync_meta_pages - META - WRITE_SYNC all the time - REQ_META | REQ_PRIO all the time ** f2fs_submit_merged_bio() handles META_FLUSH. 4. ra_nat_pages, ra_sit_pages, ra_sum_pages - META - READ_SYNC Cc: Fan Li <fanofcode.li@samsung.com> Cc: Changman Lee <cm224.lee@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: merge pages with the same sync_mode flagFan Li
Previously f2fs submits most of write requests using WRITE_SYNC, but f2fs_write_data_pages submits last write requests by sync_mode flags callers pass. This causes a performance problem since continuous pages with different sync flags can't be merged in cfq IO scheduler(thanks yu chao for pointing it out), and synchronous requests often take more time. This patch makes the following modifies to DATA writebacks: 1. every page will be written back using the sync mode caller pass. 2. only pages with the same sync mode can be merged in one bio request. These changes are restricted to DATA pages.Other types of writebacks are modified To remain synchronous. In my test with tiotest, f2fs sequence write performance is improved by about 7%-10% , and this patch has no obvious impact on other performance tests. Signed-off-by: Fan Li <fanofcode.li@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: add unlikely() macro for compiler optimizationChao Yu
As we know, some of our branch condition will rarely be true. So we could add 'unlikely' to let compiler optimize these code, by this way we could drop unneeded 'jump' assemble code to improve performance. change log: o add *unlikely* as many as possible across the whole source files at once suggested by Jaegeuk Kim. Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com> Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: refactor bio-related operationsJaegeuk Kim
This patch integrates redundant bio operations on read and write IOs. 1. Move bio-related codes to the top of data.c. 2. Replace f2fs_submit_bio with f2fs_submit_merged_bio, which handles read bios additionally. 3. Introduce __submit_merged_bio to submit the merged bio. 4. Change f2fs_readpage to f2fs_submit_page_bio. 5. Introduce f2fs_submit_page_mbio to integrate previous submit_read_page and submit_write_page. Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Reviewed-by: Chao Yu <chao2.yu@samsung.com > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: convert recover_orphan_inodes to voidChao Yu
The recover_orphan_inodes() returns no error all the time, so we don't need to check its errors. Signed-off-by: Chao Yu <chao2.yu@samsung.com> [Jaegeuk Kim: add description] Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: remove unnecessary condition checksJaegeuk Kim
This patch removes the unnecessary condition checks on: fs/f2fs/gc.c:667 do_garbage_collect() warn: 'sum_page' isn't an ERR_PTR fs/f2fs/f2fs.h:795 f2fs_put_page() warn: 'page' isn't an ERR_PTR Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: remove unnecessary return valueJaegeuk Kim
Let's remove the unnecessary return value. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: add flags and helpers to support inline dataHuajun Li
Add new inode flags F2FS_INLINE_DATA and FI_INLINE_DATA to indicate whether the inode has inline data. Inline data makes use of inode block's data indices region to save small file. Currently there are 923 data indices in an inode block. Since inline xattr has made use of the last 50 indices to save its data, there are 873 indices left which can be used for inline data. When FI_INLINE_DATA is set, the layout of inode block's indices region is like below: +-----------------+ | | Reserved. reserve_new_block() will make use of | i_addr[0] | i_addr[0] when we need to reserve a new data block | | to convert inline data into regular one's. |-----------------| | | Used by inline data. A file whose size is less than | i_addr[1~872] | 3488 bytes(~3.4k) and doesn't reserve extra | | blocks by fallocate() can be saved here. |-----------------| | | | i_addr[873~922] | Reserved for inline xattr | | +-----------------+ Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Huajun Li <huajun.li@intel.com> Signed-off-by: Weihong Xu <weihong.xu@intel.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: add a new function: f2fs_reserve_block()Huajun Li
Add the function f2fs_reserve_block() to easily reserve new blocks, and use it to clean up more codes. Signed-off-by: Huajun Li <huajun.li@intel.com> Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Weihong Xu <weihong.xu@intel.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: avoid lock debugging overheadJaegeuk Kim
If CONFIG_F2FS_CHECK_FS is unset, we don't need to add any debugging overhead. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: add a new function to support for merging contiguous readChao Yu
For better read performance, we add a new function to support for merging contiguous read as the one for write. v1-->v2: o add declarations here as Gu Zheng suggested. o use new structure f2fs_bio_info introduced by Jaegeuk Kim. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
2013-12-23f2fs: convert inc/dec_valid_node_count to inc/dec one countGu Zheng
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: convert dev_valid_block_count to voidGu Zheng
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: convert remove_inode_page to voidGu Zheng
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: introduce a bio array for per-page write biosJaegeuk Kim
The f2fs has three bio types, NODE, DATA, and META, and manages some data structures per each bio types. The codes are a little bit messy, thus, this patch introduces a bio array which groups individual data structures as follows. struct f2fs_bio_info { struct bio *bio; /* bios to merge */ sector_t last_block_in_bio; /* last block number */ struct mutex io_mutex; /* mutex for bio */ }; struct f2fs_sb_info { ... struct f2fs_bio_info write_io[NR_PAGE_TYPE]; /* for write bios */ ... }; The code changes from this new data structure are trivial. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: disable the extent cache ops on high fragmented filesJaegeuk Kim
The f2fs manages an extent cache to search a number of consecutive data blocks very quickly. However it conducts unnecessary cache operations if the file is highly fragmented with no valid extent cache. In such the case, we don't need to handle the extent cache, but just can disable the cache facility. Nevertheless, this patch gives one more chance to enable the extent cache. For example, 1. create a file 2. write data sequentially which produces a large valid extent cache 3. update some data, resulting in a fragmented extent 4. if the fragmented extent is too small, then drop extent cache 5. close the file 6. open the file again 7. give another chance to make a new extent cache 8. write data sequentially again which creates another big extent cache. ... Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: use sbi->write_mutex for write biosJaegeuk Kim
This patch removes an unnecessary semaphore (i.e., sbi->bio_sem). There is no reason to use the semaphore when f2fs submits read and write IOs. Instead, let's use a write mutex and cover the sbi->bio[] by the lock. Change log from v1: o split write_mutex suggested by Chao Yu Chao described, "All DATA/NODE/META bio buffers in superblock is protected by 'sbi->write_mutex', but each bio buffer area is independent, So we should split write_mutex to three for DATA/NODE/META." Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: clean up the do_submit_bio flowJaegeuk Kim
This patch introduces PAGE_TYPE_OF_BIO() and cleans up do_submit_bio() with it. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23f2fs: add a slab cache entry for small discardsJaegeuk Kim
This patch adds a slab cache entry for small discards. Each entry consists of: struct discard_entry { struct list_head list; /* list head */ block_t blkaddr; /* block address to be discarded */ int len; /* # of consecutive blocks of the discard */ }; Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-11-08f2fs: cleanup waiting routine for writeback pages in cpChangman Lee
use genernal method supported by kernel o changes from v1 If any waiter exists at end io, wake up it. Signed-off-by: Changman Lee <cm224.lee@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-31f2fs: avoid to wait all the node blocks during fsyncJaegeuk Kim
Previously, f2fs_sync_file() waits for all the node blocks to be written. But, we don't need to do that, but wait only the inode-related node blocks. This patch adds wait_on_node_pages_writeback() in which waits inode-related node blocks that are on writeback. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-29f2fs: add an option to avoid unnecessary BUG_ONsJaegeuk Kim
If you want to remove unnecessary BUG_ONs, you can just turn off F2FS_CHECK_FS in your kernel config. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-25f2fs: introduce f2fs_balance_fs_bg for some background jobsJaegeuk Kim
This patch merges some background jobs into this new function. Signed-off-by: Changman Lee <cm224.lee@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-25f2fs: reclaim prefree segments periodicallyJaegeuk Kim
Previously, f2fs postpones reclaiming prefree segments into free segments as much as possible. However, if user writes and deletes a bunch of data without any sync or fsync calls, some flash storages can suffer from garbage collections. So, this patch adds the reclaiming codes to f2fs_write_node_pages and background GC thread. If there are a lot of prefree segments, let's do checkpoint so that f2fs submits discard commands for the prefree regions to the flash storage. Signed-off-by: Changman Lee <cm224.lee@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-25f2fs: use bool for booleansHaicheng Li
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-25f2fs: clean up several status-related operationsJaegeuk Kim
This patch cleans up improper definitions that update some status information. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-22f2fs: introduce f2fs_kmem_cache_alloc to hide the unfailed, kmem cache ↵Gu Zheng
allocation Introduce the unfailed version of kmem_cache_alloc named f2fs_kmem_cache_alloc to hide the retry routine and make the code a bit cleaner. v2: Fix the wrong use of 'retry' tag pointed out by Gao feng. Use more neat code to remove redundant tag suggested by Haicheng Li. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-18f2fs: avoid wait if IO end up when do_checkpoint for better performanceGu Zheng
Previously, do_checkpoint() will call congestion_wait() for waiting the pages (previous submitted node/meta/data pages) to be written back. Because congestion_wait() will set a regular period (e.g. HZ / 50 ) for waiting, and no additional wake up mechanism was introduced if IO ends up before regular period costed. Yuan Zhong found there is a situation that after the pages have been written back, but the checkpoint thread still wait for congestion_wait to exit. So here we store checkpoint task into f2fs_sb when doing checkpoint, it'll wait for IO completes if there's IO going on, and in the end IO path, wake up checkpoint task when IO ends up. Thanks to Yuan Zhong's pre work about this problem. Reported-by: Yuan Zhong <yuan.mark.zhong@samsung.com> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-18f2fs: fix the starvation problem on cp_rwsemJaegeuk Kim
This patch removes the logic previously introduced to address the starvation on cp_rwsem. One potential there-in bug is that we should cover the wait.list with spin_lock, but the previous code broke this rule. And, actually current rwsem handles this starvation issue reasonably, so that we didn't need to do this before neither. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-10-07f2fs: use rw_sem instead of fs_lock(locks mutex)Gu Zheng
The fs_locks is used to block other ops(ex, recovery) when doing checkpoint. And each other operate routine(besides checkpoint) needs to acquire a fs_lock, there is a terrible problem here, if these are too many concurrency threads acquiring fs_lock, so that they will block each other and may lead to some performance problem, but this is not the phenomenon we want to see. Though there are some optimization patches introduced to enhance the usage of fs_lock, but the thorough solution is using a *rw_sem* to replace the fs_lock. Checkpoint routine takes write_sem, and other ops take read_sem, so that we can block other ops(ex, recovery) when doing checkpoint, and other ops will not disturb each other, this can avoid the problem described above completely. Because of the weakness of rw_sem, the above change may introduce a potential problem that the checkpoint thread might get starved if other threads are intensively locking the read semaphore for I/O.(Pointed out by Xu Jin) In order to avoid this, a wait_list is introduced, the appending read semaphore ops will be dropped into the wait_list if checkpoint thread is waiting for write semaphore, and will be waked up when checkpoint thread gives up write semaphore. Thanks to Kim's previous review and test, and will be very glad to see other guys' performance tests about this patch. V2: -fix the potential starvation problem. -use more suitable func name suggested by Xu Jin. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> [Jaegeuk Kim: adjust minor coding standard] Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-09-24f2fs: optimize fs_lock for better performanceYu Chao
There is a performance problem: when all sbi->fs_lock are holded, then all the following threads may get the same next_lock value from sbi->next_lock_num in function mutex_lock_op, and wait for the same lock(fs_lock[next_lock]), it may cause performance reduce. So we move the sbi->next_lock_num++ before getting lock, this will average the following threads if all sbi->fs_lock are holded. v1-->v2: Drop the needless spin_lock as Jaegeuk suggested. Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com> Signed-off-by: Yu Chao <chao2.yu@samsung.com> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>