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ext4: count hits/misses of extent cache and expose in sysfs

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The number of hits and misses for each filesystem is exposed in
/sys/fs/ext4/<dev>/extent_cache_{hits, misses}.

Tested: fsstress, manual checks.
Signed-off-by: Vivek Haldar <haldar@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Vivek Haldar
2011-05-22 21:24:16 -04:00
committed by Theodore Ts'o
parent 93917411be
commit 77f4135f2a
3 changed files with 25 additions and 1 deletions
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3
fs/ext4/ext4.h
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@@ -1144,6 +1144,9 @@ struct ext4_sb_info {
unsigned long s_ext_blocks; unsigned long s_ext_blocks;
unsigned long s_ext_extents; unsigned long s_ext_extents;
#endif #endif
/* ext4 extent cache stats */
unsigned long extent_cache_hits;
unsigned long extent_cache_misses;
/* for buddy allocator */ /* for buddy allocator */
struct ext4_group_info ***s_group_info; struct ext4_group_info ***s_group_info;

7
fs/ext4/extents.c
View File

@@ -2035,6 +2035,7 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
struct ext4_extent *ex) struct ext4_extent *ex)
{ {
struct ext4_ext_cache *cex; struct ext4_ext_cache *cex;
struct ext4_sb_info *sbi;
int ret = 0; int ret = 0;
/* /*
@@ -2042,6 +2043,7 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
*/ */
spin_lock(&EXT4_I(inode)->i_block_reservation_lock); spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
cex = &EXT4_I(inode)->i_cached_extent; cex = &EXT4_I(inode)->i_cached_extent;
sbi = EXT4_SB(inode->i_sb);
/* has cache valid data? */ /* has cache valid data? */
if (cex->ec_len == 0) if (cex->ec_len == 0)
@@ -2057,6 +2059,10 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
ret = 1; ret = 1;
} }
errout: errout:
if (!ret)
sbi->extent_cache_misses++;
else
sbi->extent_cache_hits++;
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
return ret; return ret;
} }
@@ -3901,4 +3907,3 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
return error; return error;
} }

16
fs/ext4/super.c
View File

@@ -2439,6 +2439,18 @@ static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
EXT4_SB(sb)->s_sectors_written_start) >> 1))); EXT4_SB(sb)->s_sectors_written_start) >> 1)));
} }
static ssize_t extent_cache_hits_show(struct ext4_attr *a,
struct ext4_sb_info *sbi, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_hits);
}
static ssize_t extent_cache_misses_show(struct ext4_attr *a,
struct ext4_sb_info *sbi, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_misses);
}
static ssize_t inode_readahead_blks_store(struct ext4_attr *a, static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
struct ext4_sb_info *sbi, struct ext4_sb_info *sbi,
const char *buf, size_t count) const char *buf, size_t count)
@@ -2496,6 +2508,8 @@ static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
EXT4_RO_ATTR(delayed_allocation_blocks); EXT4_RO_ATTR(delayed_allocation_blocks);
EXT4_RO_ATTR(session_write_kbytes); EXT4_RO_ATTR(session_write_kbytes);
EXT4_RO_ATTR(lifetime_write_kbytes); EXT4_RO_ATTR(lifetime_write_kbytes);
EXT4_RO_ATTR(extent_cache_hits);
EXT4_RO_ATTR(extent_cache_misses);
EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show, EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
inode_readahead_blks_store, s_inode_readahead_blks); inode_readahead_blks_store, s_inode_readahead_blks);
EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
@@ -2511,6 +2525,8 @@ static struct attribute *ext4_attrs[] = {
ATTR_LIST(delayed_allocation_blocks), ATTR_LIST(delayed_allocation_blocks),
ATTR_LIST(session_write_kbytes), ATTR_LIST(session_write_kbytes),
ATTR_LIST(lifetime_write_kbytes), ATTR_LIST(lifetime_write_kbytes),
ATTR_LIST(extent_cache_hits),
ATTR_LIST(extent_cache_misses),
ATTR_LIST(inode_readahead_blks), ATTR_LIST(inode_readahead_blks),
ATTR_LIST(inode_goal), ATTR_LIST(inode_goal),
ATTR_LIST(mb_stats), ATTR_LIST(mb_stats),