f2fs: update extent tree in batches
This patch introduce a new helper f2fs_update_extent_tree_range which can
do extent mapping update at a specified range.
The main idea is:
1) punch all mapping info in extent node(s) which are at a specified range;
2) try to merge new extent mapping with adjacent node, or failing that,
insert the mapping into extent tree as a new node.
In order to see the benefit, I add a function for stating time stamping
count as below:
uint64_t rdtsc(void)
{
uint32_t lo, hi;
__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
return (uint64_t)hi << 32 | lo;
}
My test environment is: ubuntu, intel i7-3770, 16G memory, 256g micron ssd.
truncation path: update extent cache from truncate_data_blocks_range
non-truncataion path: update extent cache from other paths
total: all update paths
a) Removing 128MB file which has one extent node mapping whole range of
file:
1. dd if=/dev/zero of=/mnt/f2fs/128M bs=1M count=128
2. sync
3. rm /mnt/f2fs/128M
Before:
total count average
truncation: 7651022 32768 233.49
Patched:
total count average
truncation: 3321 33 100.64
b) fsstress:
fsstress -d /mnt/f2fs -l 5 -n 100 -p 20
Test times: 5 times.
Before:
total count average
truncation: 5812480.6 20911.6 277.95
non-truncation: 7783845.6 13440.8 579.12
total: 13596326.2 34352.4 395.79
Patched:
total count average
truncation: 1281283.0 3041.6 421.25
non-truncation: 7355844.4 13662.8 538.38
total: 8637127.4 16704.4 517.06
1) For the updates in truncation path:
- we can see updating in batches leads total tsc and update count reducing
explicitly;
- besides, for a single batched updating, punching multiple extent nodes
in a loop, result in executing more operations, so our average tsc
increase intensively.
2) For the updates in non-truncation path:
- there is a little improvement, that is because for the scenario that we
just need to update in the head or tail of extent node, new interface
optimize to update info in extent node directly, rather than removing
original extent node for updating and then inserting that updated one
into cache as new node.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 69827ee..f1a90ff 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2017,6 +2017,8 @@
void f2fs_destroy_extent_tree(struct inode *);
bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);
void f2fs_update_extent_cache(struct dnode_of_data *);
+void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
+ pgoff_t, block_t, unsigned int);
void init_extent_cache_info(struct f2fs_sb_info *);
int __init create_extent_cache(void);
void destroy_extent_cache(void);