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kernel-ark/fs/ext4/extents_status.h

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ext4: add data structures for the extent status tree This patch adds two structures that supports extent status tree, extent_status and ext4_es_tree. Currently extent_status is used to track a delay extent for an inode, which record the start block and the length of the delay extent. ext4_es_tree is used to store all extent_status for an inode in memory. Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-11-08 20:18:54 +00:00
/*
* fs/ext4/extents_status.h
*
* Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
* Modified by
* Allison Henderson <achender@linux.vnet.ibm.com>
* Zheng Liu <wenqing.lz@taobao.com>
*
*/
#ifndef _EXT4_EXTENTS_STATUS_H
#define _EXT4_EXTENTS_STATUS_H
ext4: add operations on extent status tree 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>
2012-11-09 02:57:20 +00:00
/*
* Turn on ES_DEBUG__ to get lots of info about extent status operations.
*/
#ifdef ES_DEBUG__
#define es_debug(fmt, ...) printk(fmt, ##__VA_ARGS__)
#else
#define es_debug(fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#endif
ext4: add self-testing infrastructure to do a sanity check 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>
2013-03-11 01:01:03 +00:00
/*
* With ES_AGGRESSIVE_TEST defined, the result of es caching will be
* checked with old map_block's result.
*/
#define ES_AGGRESSIVE_TEST__
ext4: fix extent status tree regression for file systems > 512GB This fixes a regression introduced by commit f7fec032aa782. The problem was that the extents status flags caused us to mask out block numbers smaller than 2**28 blocks. Since we didn't test with file systems smaller than 512GB, we didn't notice this during the development cycle. A typical failure looks like this: EXT4-fs error (device sdb1): htree_dirblock_to_tree:919: inode #172235804: block 152052301: comm ls: bad entry in directory: rec_len is smaller than minimal - offset=0(0), inode=0, rec_len=0, name_len=0 ... where 'debugfs -R "stat <172235804>" /dev/sdb1' reports that the inode has block number 688923213. When viewed in hex, block number 152052301 (from the syslog) is 0x910224D, while block number 688923213 is 0x2910224D. Note the missing "0x20000000" in the block number. Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Verified-by: Markus Trippelsdorf <markus@trippelsdorf.de> Reported-by: Dave Jones <davej@redhat.com> Verified-by: Dave Jones <davej@redhat.com> Cc: Zheng Liu <gnehzuil.liu@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-02-27 19:54:37 +00:00
/*
* These flags live in the high bits of extent_status.es_pblk
*/
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
enum {
ES_WRITTEN_B,
ES_UNWRITTEN_B,
ES_DELAYED_B,
ES_HOLE_B,
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
ES_REFERENCED_B,
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
ES_FLAGS
};
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
#define ES_SHIFT (sizeof(ext4_fsblk_t)*8 - ES_FLAGS)
#define ES_MASK (~((ext4_fsblk_t)0) << ES_SHIFT)
ext4: use unsigned int for es_status values 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>
2013-08-17 01:22:41 +00:00
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
#define EXTENT_STATUS_WRITTEN (1 << ES_WRITTEN_B)
#define EXTENT_STATUS_UNWRITTEN (1 << ES_UNWRITTEN_B)
#define EXTENT_STATUS_DELAYED (1 << ES_DELAYED_B)
#define EXTENT_STATUS_HOLE (1 << ES_HOLE_B)
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
#define EXTENT_STATUS_REFERENCED (1 << ES_REFERENCED_B)
#define ES_TYPE_MASK ((ext4_fsblk_t)(EXTENT_STATUS_WRITTEN | \
EXTENT_STATUS_UNWRITTEN | \
EXTENT_STATUS_DELAYED | \
EXTENT_STATUS_HOLE) << ES_SHIFT)
ext4: use unsigned int for es_status values 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>
2013-08-17 01:22:41 +00:00
ext4: improve extent cache shrink mechanism to avoid to burn CPU time 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>
2013-07-01 12:12:37 +00:00
struct ext4_sb_info;
ext4: update extent status tree after an extent is zeroed out 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>
2013-03-11 01:13:05 +00:00
struct ext4_extent;
ext4: add data structures for the extent status tree This patch adds two structures that supports extent status tree, extent_status and ext4_es_tree. Currently extent_status is used to track a delay extent for an inode, which record the start block and the length of the delay extent. ext4_es_tree is used to store all extent_status for an inode in memory. Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-11-08 20:18:54 +00:00
struct extent_status {
struct rb_node rb_node;
ext4: refine extent status tree 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>
2013-02-18 05:26:51 +00:00
ext4_lblk_t es_lblk; /* first logical block extent covers */
ext4_lblk_t es_len; /* length of extent in block */
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
ext4_fsblk_t es_pblk; /* first physical block */
ext4: add data structures for the extent status tree This patch adds two structures that supports extent status tree, extent_status and ext4_es_tree. Currently extent_status is used to track a delay extent for an inode, which record the start block and the length of the delay extent. ext4_es_tree is used to store all extent_status for an inode in memory. Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-11-08 20:18:54 +00:00
};
struct ext4_es_tree {
struct rb_root root;
struct extent_status *cache_es; /* recently accessed extent */
};
ext4: track extent status tree shrinker delay statictics 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>
2014-09-02 02:26:49 +00:00
struct ext4_es_stats {
unsigned long es_stats_shrunk;
unsigned long es_stats_cache_hits;
unsigned long es_stats_cache_misses;
u64 es_stats_scan_time;
u64 es_stats_max_scan_time;
struct percpu_counter es_stats_all_cnt;
ext4: change LRU to round-robin in extent status tree shrinker 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>
2014-11-25 16:45:37 +00:00
struct percpu_counter es_stats_shk_cnt;
ext4: track extent status tree shrinker delay statictics 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>
2014-09-02 02:26:49 +00:00
};
ext4: add operations on extent status tree 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>
2012-11-09 02:57:20 +00:00
extern int __init ext4_init_es(void);
extern void ext4_exit_es(void);
extern void ext4_es_init_tree(struct ext4_es_tree *tree);
ext4: refine extent status tree 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>
2013-02-18 05:26:51 +00:00
extern int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
ext4_lblk_t len, ext4_fsblk_t pblk,
ext4: use unsigned int for es_status values 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>
2013-08-17 01:22:41 +00:00
unsigned int status);
ext4: cache all of an extent tree's leaf block upon reading 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>
2013-08-17 01:23:41 +00:00
extern void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len, ext4_fsblk_t pblk,
unsigned int status);
ext4: refine extent status tree 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>
2013-02-18 05:26:51 +00:00
extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
ext4: add operations on extent status tree 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>
2012-11-09 02:57:20 +00:00
ext4_lblk_t len);
ext4: fix fio regression 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>
2013-05-03 06:15:52 +00:00
extern void ext4_es_find_delayed_extent_range(struct inode *inode,
ext4_lblk_t lblk, ext4_lblk_t end,
ext4: rename and improbe ext4_es_find_extent() 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>
2013-02-18 05:27:26 +00:00
struct extent_status *es);
ext4: lookup block mapping in extent status tree 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>
2013-02-18 05:29:59 +00:00
extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
struct extent_status *es);
ext4: add operations on extent status tree 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>
2012-11-09 02:57:20 +00:00
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
static inline unsigned int ext4_es_status(struct extent_status *es)
{
return es->es_pblk >> ES_SHIFT;
}
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
static inline unsigned int ext4_es_type(struct extent_status *es)
{
return (es->es_pblk & ES_TYPE_MASK) >> ES_SHIFT;
}
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
static inline int ext4_es_is_written(struct extent_status *es)
{
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
return (ext4_es_type(es) & EXTENT_STATUS_WRITTEN) != 0;
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
}
static inline int ext4_es_is_unwritten(struct extent_status *es)
{
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
return (ext4_es_type(es) & EXTENT_STATUS_UNWRITTEN) != 0;
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
}
static inline int ext4_es_is_delayed(struct extent_status *es)
{
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
return (ext4_es_type(es) & EXTENT_STATUS_DELAYED) != 0;
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
}
static inline int ext4_es_is_hole(struct extent_status *es)
{
ext4: introduce aging to extent status tree 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>
2014-11-25 16:55:24 +00:00
return (ext4_es_type(es) & EXTENT_STATUS_HOLE) != 0;
}
static inline void ext4_es_set_referenced(struct extent_status *es)
{
es->es_pblk |= ((ext4_fsblk_t)EXTENT_STATUS_REFERENCED) << ES_SHIFT;
}
static inline void ext4_es_clear_referenced(struct extent_status *es)
{
es->es_pblk &= ~(((ext4_fsblk_t)EXTENT_STATUS_REFERENCED) << ES_SHIFT);
}
static inline int ext4_es_is_referenced(struct extent_status *es)
{
return (ext4_es_status(es) & EXTENT_STATUS_REFERENCED) != 0;
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
}
static inline ext4_fsblk_t ext4_es_pblock(struct extent_status *es)
{
ext4: use unsigned int for es_status values 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>
2013-08-17 01:22:41 +00:00
return es->es_pblk & ~ES_MASK;
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
}
static inline void ext4_es_store_pblock(struct extent_status *es,
ext4_fsblk_t pb)
{
ext4_fsblk_t block;
ext4: use unsigned int for es_status values 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>
2013-08-17 01:22:41 +00:00
block = (pb & ~ES_MASK) | (es->es_pblk & ES_MASK);
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
es->es_pblk = block;
}
static inline void ext4_es_store_status(struct extent_status *es,
ext4: use unsigned int for es_status values 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>
2013-08-17 01:22:41 +00:00
unsigned int status)
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
{
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
es->es_pblk = (((ext4_fsblk_t)status << ES_SHIFT) & ES_MASK) |
(es->es_pblk & ~ES_MASK);
ext4: add physical block and status member into extent status tree 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>
2013-02-18 05:26:51 +00:00
}
ext4: add ext4_es_store_pblock_status() 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>
2014-02-20 01:15:15 +00:00
static inline void ext4_es_store_pblock_status(struct extent_status *es,
ext4_fsblk_t pb,
unsigned int status)
{
ext4: cleanup flag definitions for extent status tree 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>
2014-11-25 16:53:47 +00:00
es->es_pblk = (((ext4_fsblk_t)status << ES_SHIFT) & ES_MASK) |
(pb & ~ES_MASK);
ext4: add ext4_es_store_pblock_status() 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>
2014-02-20 01:15:15 +00:00
}
ext4: track extent status tree shrinker delay statictics 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>
2014-09-02 02:26:49 +00:00
extern int ext4_es_register_shrinker(struct ext4_sb_info *sbi);
ext4: improve extent cache shrink mechanism to avoid to burn CPU time 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>
2013-07-01 12:12:37 +00:00
extern void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi);
ext4: reclaim extents from extent status tree 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>
2013-02-18 05:32:55 +00:00
ext4: add data structures for the extent status tree This patch adds two structures that supports extent status tree, extent_status and ext4_es_tree. Currently extent_status is used to track a delay extent for an inode, which record the start block and the length of the delay extent. ext4_es_tree is used to store all extent_status for an inode in memory. Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-11-08 20:18:54 +00:00
#endif /* _EXT4_EXTENTS_STATUS_H */
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