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f2fs: introduce check_swap_activate_fast()

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check_swap_activate() will lookup block mapping via bmap() one by one, so
its performance is very bad, this patch introduces check_swap_activate_fast()
to use f2fs_fiemap() to boost this process, since f2fs_fiemap() will lookup
block mappings in batch, therefore, it can improve swapon()'s performance
significantly.

Note that this enhancement only works when page size is equal to f2fs' block
size.

Testcase: (backend device: zram)
- touch file
- pin & fallocate file to 8GB
- mkswap file
- swapon file

Before:
real	0m2.999s
user	0m0.000s
sys	0m2.980s

After:
real	0m0.081s
user	0m0.000s
sys	0m0.064s

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Chao Yu 2020-10-12 17:06:05 +08:00 committed by Jaegeuk Kim
parent 6ed29fe1ca
commit af4b6b8edf
1 changed files with 80 additions and 0 deletions
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80
fs/f2fs/data.c
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@ -3883,6 +3883,83 @@ int f2fs_migrate_page(struct address_space *mapping,
#endif
#ifdef CONFIG_SWAP
static int check_swap_activate_fast(struct swap_info_struct *sis,
struct file *swap_file, sector_t *span)
{
struct address_space *mapping = swap_file->f_mapping;
struct inode *inode = mapping->host;
sector_t cur_lblock;
sector_t last_lblock;
sector_t pblock;
sector_t lowest_pblock = -1;
sector_t highest_pblock = 0;
int nr_extents = 0;
unsigned long nr_pblocks;
unsigned long len;
int ret;
/*
* Map all the blocks into the extent list. This code doesn't try
* to be very smart.
*/
cur_lblock = 0;
last_lblock = logical_to_blk(inode, i_size_read(inode));
len = i_size_read(inode);
while (cur_lblock <= last_lblock && cur_lblock < sis->max) {
struct buffer_head map_bh;
pgoff_t next_pgofs;
cond_resched();
memset(&map_bh, 0, sizeof(struct buffer_head));
map_bh.b_size = len - cur_lblock;
ret = get_data_block(inode, cur_lblock, &map_bh, 0,
F2FS_GET_BLOCK_FIEMAP, &next_pgofs);
if (ret)
goto err_out;
/* hole */
if (!buffer_mapped(&map_bh))
goto err_out;
pblock = map_bh.b_blocknr;
nr_pblocks = logical_to_blk(inode, map_bh.b_size);
if (cur_lblock + nr_pblocks >= sis->max)
nr_pblocks = sis->max - cur_lblock;
if (cur_lblock) { /* exclude the header page */
if (pblock < lowest_pblock)
lowest_pblock = pblock;
if (pblock + nr_pblocks - 1 > highest_pblock)
highest_pblock = pblock + nr_pblocks - 1;
}
/*
* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
*/
ret = add_swap_extent(sis, cur_lblock, nr_pblocks, pblock);
if (ret < 0)
goto out;
nr_extents += ret;
cur_lblock += nr_pblocks;
}
ret = nr_extents;
*span = 1 + highest_pblock - lowest_pblock;
if (cur_lblock == 0)
cur_lblock = 1; /* force Empty message */
sis->max = cur_lblock;
sis->pages = cur_lblock - 1;
sis->highest_bit = cur_lblock - 1;
out:
return ret;
err_out:
pr_err("swapon: swapfile has holes\n");
return -EINVAL;
}
/* Copied from generic_swapfile_activate() to check any holes */
static int check_swap_activate(struct swap_info_struct *sis,
struct file *swap_file, sector_t *span)
@ -3899,6 +3976,9 @@ static int check_swap_activate(struct swap_info_struct *sis,
int nr_extents = 0;
int ret;
if (PAGE_SIZE == F2FS_BLKSIZE)
return check_swap_activate_fast(sis, swap_file, span);
blkbits = inode->i_blkbits;
blocks_per_page = PAGE_SIZE >> blkbits;