Re: [PATCH v2] f2fs: build free nid bitmap during flush nat entries

[Chao Yu <chao@kernel.org>]

On 2018/4/25 16:07, heyunlei wrote:
> 
> 
>> -----Original Message-----
>> From: heyunlei
>> Sent: Wednesday, April 25, 2018 3:44 PM
>> To: jaegeuk@kernel.org; Yuchao (T); linux-f2fs-devel@lists.sourceforge.net
>> Cc: Wangbintian; heyunlei; Zhangdianfang (Euler)
>> Subject: [f2fs-dev][PATCH v2] f2fs: build free nid bitmap during flush nat entries
>>
>> This patch introduce free nid bitmap build during flush
>> nat entries in order to reduce synchronous read in the
>> process of build free nids.
>>
>> Signed-off-by: Yunlei He <heyunlei@huawei.com>
>> ---
>> fs/f2fs/node.c | 11 ++++++++---
>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index f202398..681552b 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -1947,7 +1947,7 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
>> }
>>
>> static void scan_nat_page(struct f2fs_sb_info *sbi,
>> -			struct page *nat_page, nid_t start_nid)
>> +		struct page *nat_page, nid_t start_nid, bool in_build)
>> {
>> 	struct f2fs_nm_info *nm_i = NM_I(sbi);
>> 	struct f2fs_nat_block *nat_blk = page_address(nat_page);
>> @@ -1955,6 +1955,9 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
>> 	unsigned int nat_ofs = NAT_BLOCK_OFFSET(start_nid);
>> 	int i;
>>
>> +	if (!test_bit_le(nat_ofs, nm_i->nat_block_bitmap))
>> +		return;
>> +
> Sorry that it should be:
> 	if (test_bit_le(nat_ofs, nm_i->nat_block_bitmap))
> 		return;
> 
> Thanks.
>> 	__set_bit_le(nat_ofs, nm_i->nat_block_bitmap);
>>
>> 	i = start_nid % NAT_ENTRY_PER_BLOCK;
>> @@ -1966,7 +1969,8 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
>> 		blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
>> 		f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
>> 		if (blk_addr == NULL_ADDR) {
>> -			add_free_nid(sbi, start_nid, true, true);
>> +			if (in_build)
>> +				add_free_nid(sbi, start_nid, true, true);

We should call update_free_nid_bitmap instead of skipping add_free_nid, so how
about:

if (update_bitmap) {
	spin_lock;
	update_free_nid_bitmap;
	spin_unlock;
} else {
	add_free_nid;
}

Thanks,

>> 		} else {
>> 			spin_lock(&NM_I(sbi)->nid_list_lock);
>> 			update_free_nid_bitmap(sbi, start_nid, false, true);
>> @@ -2063,7 +2067,7 @@ static void __build_free_nids(struct f2fs_sb_info *sbi, bool sync, bool mount)
>> 						nm_i->nat_block_bitmap)) {
>> 			struct page *page = get_current_nat_page(sbi, nid);
>>
>> -			scan_nat_page(sbi, page, nid);
>> +			scan_nat_page(sbi, page, nid, true);
>> 			f2fs_put_page(page, 1);
>> 		}
>>
>> @@ -2534,6 +2538,7 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>> 	if (to_journal) {
>> 		up_write(&curseg->journal_rwsem);
>> 	} else {
>> +		scan_nat_page(sbi, page, start_nid, false);
>> 		__update_nat_bits(sbi, start_nid, page);
>> 		f2fs_put_page(page, 1);
>> 	}
>> --
>> 1.9.1
> 
> 
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot