Hi Yu,
On 06/25/2014 10:30 AM, Chao Yu wrote:
> Hi Gu,
>
> Just one nitpick.
>
>> -----Original Message-----
>> From: Gu Zheng [mailto:guz.f...@cn.fujitsu.com]
>> Sent: Tuesday, June 24, 2014 6:21 PM
>> To: Jaegeuk Kim
>> Cc: fsdevel; f2fs
>> Subject: [f2fs-dev] [PATCH 3/4] f2fs: use find_next_bit_le rather than
>> test_bit_le in,
>> find_in_block
>>
>> Use find_next_bit_le rather than test_bit_le to improve search speed
>> lightly.
>>
>> Signed-off-by: Gu Zheng <guz.f...@cn.fujitsu.com>
>> ---
>> fs/f2fs/dir.c | 43 +++++++++++++++++++++----------------------
>> 1 files changed, 21 insertions(+), 22 deletions(-)
>>
>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>> index 3edd561..ba510fb 100644
>> --- a/fs/f2fs/dir.c
>> +++ b/fs/f2fs/dir.c
>> @@ -93,42 +93,41 @@ static struct f2fs_dir_entry *find_in_block(struct page
>> *dentry_page,
>> const char *name, size_t namelen, int *max_slots,
>> f2fs_hash_t namehash, struct page **res_page)
>> {
>> - struct f2fs_dir_entry *de;
>> - unsigned long bit_pos = 0;
>> + unsigned long bit_pos = 0, bit_start = 0;
>> struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);
>> const void *dentry_bits = &dentry_blk->dentry_bitmap;
>> - int max_len = 0;
>>
>> - while (bit_pos < NR_DENTRY_IN_BLOCK) {
>> - if (!test_bit_le(bit_pos, dentry_bits)) {
>> - if (bit_pos == 0)
>> - max_len = 1;
>> - else if (!test_bit_le(bit_pos - 1, dentry_bits))
>> - max_len++;
>> - bit_pos++;
>> - continue;
>> + while (bit_start < NR_DENTRY_IN_BLOCK) {
>> + struct f2fs_dir_entry *de;
>> + int max_len = 0;
>> +
>> + bit_pos = find_next_bit_le(dentry_bits,
>> + NR_DENTRY_IN_BLOCK, bit_start);
>> +
>> + max_len = bit_pos - bit_start;
>> + if (max_len > *max_slots) {
>> + *max_slots = max_len;
>> + max_len = 0;
>
> It could be removed here, and also do not need to initialize above.
Nice catch, thanks.;)
Regards,
Gu
>
> Thanks.
> Yu
>
>> }
>> +
>> + if (bit_pos >= NR_DENTRY_IN_BLOCK)
>> + break;
>> +
>> de = &dentry_blk->dentry[bit_pos];
>> if (early_match_name(name, namelen, namehash, de)) {
>> if (!memcmp(dentry_blk->filename[bit_pos],
>> name, namelen)) {
>> *res_page = dentry_page;
>> - goto found;
>> + return de;
>> }
>> }
>> - if (max_len > *max_slots) {
>> - *max_slots = max_len;
>> - max_len = 0;
>> - }
>> - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
>> +
>> + bit_start = bit_pos
>> + + GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
>> }
>>
>> - de = NULL;
>> kunmap(dentry_page);
>> -found:
>> - if (max_len > *max_slots)
>> - *max_slots = max_len;
>> - return de;
>> + return NULL;
>> }
>>
>> static struct f2fs_dir_entry *find_in_level(struct inode *dir,
>> --
>> 1.7.7
>>
>>
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>
> .
>
------------------------------------------------------------------------------
Open source business process management suite built on Java and Eclipse
Turn processes into business applications with Bonita BPM Community Edition
Quickly connect people, data, and systems into organized workflows
Winner of BOSSIE, CODIE, OW2 and Gartner awards
http://p.sf.net/sfu/Bonitasoft
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