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Message-ID: <b84afb5e-2ea9-79c3-f95d-94dc1a4f9eb2@huawei.com>
Date: Fri, 13 Jul 2018 11:42:11 +0800
From: Yunlong Song <yunlong.song@...wei.com>
To: Chao Yu <yuchao0@...wei.com>, <jaegeuk@...nel.org>,
<chao@...nel.org>, <yunlong.song@...oud.com>
CC: <miaoxie@...wei.com>, <bintian.wang@...wei.com>,
<shengyong1@...wei.com>, <heyunlei@...wei.com>,
<linux-f2fs-devel@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/5] f2fs: do not __punch_discard_cmd in lfs mode
How about change test_opt(sbi, LFS) to f2fs_sb_has_blkzoned(sbi->sb) in
this patch, which can
avoid punch discard (creating small discard) in zoned block device.
On 2018/7/13 11:26, Chao Yu wrote:
> On 2018/7/12 23:09, Yunlong Song wrote:
>> In lfs mode, it is better to submit and wait for discard of the
>> new_blkaddr's overall section, rather than punch it which makes
>> more small discards and is not friendly with flash alignment. And
>> f2fs does not have to wait discard of each new_blkaddr except for the
>> start_block of each section with this patch.
> For non-zoned block device, unaligned discard can be allowed; and if synchronous
> discard is very slow, it will block block allocator here, rather than that, I
> prefer just punch 4k lba of discard entry for performance.
>
> If you don't want to encounter this condition, I suggest issue large size
> discard more quickly.
>
> Thanks,
>
>> Signed-off-by: Yunlong Song <yunlong.song@...wei.com>
>> ---
>> fs/f2fs/segment.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
>> fs/f2fs/segment.h | 7 ++++-
>> 2 files changed, 75 insertions(+), 8 deletions(-)
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index f6c20e0..bce321a 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -893,7 +893,19 @@ static void __remove_discard_cmd(struct f2fs_sb_info *sbi,
>> static void f2fs_submit_discard_endio(struct bio *bio)
>> {
>> struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
>> + struct f2fs_sb_info *sbi = F2FS_SB(dc->bdev->bd_super);
>>
>> + if (test_opt(sbi, LFS)) {
>> + unsigned int segno = GET_SEGNO(sbi, dc->lstart);
>> + unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
>> + int cnt = (dc->len >> sbi->log_blocks_per_seg) /
>> + sbi->segs_per_sec;
>> +
>> + while (cnt--) {
>> + set_bit(secno, FREE_I(sbi)->discard_secmap);
>> + secno++;
>> + }
>> + }
>> dc->error = blk_status_to_errno(bio->bi_status);
>> dc->state = D_DONE;
>> complete_all(&dc->wait);
>> @@ -1349,8 +1361,15 @@ static void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
>> dc = (struct discard_cmd *)f2fs_lookup_rb_tree(&dcc->root,
>> NULL, blkaddr);
>> if (dc) {
>> - if (dc->state == D_PREP) {
>> + if (dc->state == D_PREP && !test_opt(sbi, LFS))
>> __punch_discard_cmd(sbi, dc, blkaddr);
>> + else if (dc->state == D_PREP && test_opt(sbi, LFS)) {
>> + struct discard_policy dpolicy;
>> +
>> + __init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);
>> + __submit_discard_cmd(sbi, &dpolicy, dc);
>> + dc->ref++;
>> + need_wait = true;
>> } else {
>> dc->ref++;
>> need_wait = true;
>> @@ -2071,9 +2090,10 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
>> unsigned int hint = GET_SEC_FROM_SEG(sbi, *newseg);
>> unsigned int old_zoneno = GET_ZONE_FROM_SEG(sbi, *newseg);
>> unsigned int left_start = hint;
>> - bool init = true;
>> + bool init = true, check_discard = test_opt(sbi, LFS) ? true : false;
>> int go_left = 0;
>> int i;
>> + unsigned long *free_secmap;
>>
>> spin_lock(&free_i->segmap_lock);
>>
>> @@ -2084,11 +2104,25 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
>> goto got_it;
>> }
>> find_other_zone:
>> - secno = find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi), hint);
>> + if (check_discard) {
>> + int entries = f2fs_bitmap_size(MAIN_SECS(sbi)) / sizeof(unsigned long);
>> +
>> + free_secmap = free_i->tmp_secmap;
>> + for (i = 0; i < entries; i++)
>> + free_secmap[i] = (!(free_i->free_secmap[i] ^
>> + free_i->discard_secmap[i])) | free_i->free_secmap[i];
>> + } else
>> + free_secmap = free_i->free_secmap;
>> +
>> + secno = find_next_zero_bit(free_secmap, MAIN_SECS(sbi), hint);
>> if (secno >= MAIN_SECS(sbi)) {
>> if (dir == ALLOC_RIGHT) {
>> - secno = find_next_zero_bit(free_i->free_secmap,
>> + secno = find_next_zero_bit(free_secmap,
>> MAIN_SECS(sbi), 0);
>> + if (secno >= MAIN_SECS(sbi) && check_discard) {
>> + check_discard = false;
>> + goto find_other_zone;
>> + }
>> f2fs_bug_on(sbi, secno >= MAIN_SECS(sbi));
>> } else {
>> go_left = 1;
>> @@ -2098,13 +2132,17 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
>> if (go_left == 0)
>> goto skip_left;
>>
>> - while (test_bit(left_start, free_i->free_secmap)) {
>> + while (test_bit(left_start, free_secmap)) {
>> if (left_start > 0) {
>> left_start--;
>> continue;
>> }
>> - left_start = find_next_zero_bit(free_i->free_secmap,
>> + left_start = find_next_zero_bit(free_secmap,
>> MAIN_SECS(sbi), 0);
>> + if (left_start >= MAIN_SECS(sbi) && check_discard) {
>> + check_discard = false;
>> + goto find_other_zone;
>> + }
>> f2fs_bug_on(sbi, left_start >= MAIN_SECS(sbi));
>> break;
>> }
>> @@ -2719,7 +2757,18 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>>
>> *new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
>>
>> - f2fs_wait_discard_bio(sbi, *new_blkaddr);
>> + if (test_opt(sbi, LFS)) {
>> + unsigned int start_segno, secno;
>> +
>> + secno = GET_SEC_FROM_SEG(sbi, curseg->segno);
>> + start_segno = secno * sbi->segs_per_sec;
>> + if (*new_blkaddr == START_BLOCK(sbi, start_segno) &&
>> + !test_bit(secno, FREE_I(sbi)->discard_secmap))
>> + f2fs_wait_discard_bio(sbi, *new_blkaddr);
>> + f2fs_bug_on(sbi, !test_bit(secno, FREE_I(sbi)->discard_secmap));
>> + }
>> + else
>> + f2fs_wait_discard_bio(sbi, *new_blkaddr);
>>
>> /*
>> * __add_sum_entry should be resided under the curseg_mutex
>> @@ -3648,10 +3697,21 @@ static int build_free_segmap(struct f2fs_sb_info *sbi)
>> if (!free_i->free_secmap)
>> return -ENOMEM;
>>
>> + free_i->discard_secmap = f2fs_kvmalloc(sbi, sec_bitmap_size, GFP_KERNEL);
>> + if (!free_i->discard_secmap)
>> + return -ENOMEM;
>> +
>> + free_i->tmp_secmap = f2fs_kvmalloc(sbi, sec_bitmap_size, GFP_KERNEL);
>> + if (!free_i->tmp_secmap)
>> + return -ENOMEM;
>> +
>> /* set all segments as dirty temporarily */
>> memset(free_i->free_segmap, 0xff, bitmap_size);
>> memset(free_i->free_secmap, 0xff, sec_bitmap_size);
>>
>> + /* set all sections as discarded temporarily */
>> + memset(free_i->discard_secmap, 0xff, sec_bitmap_size);
>> +
>> /* init free segmap information */
>> free_i->start_segno = GET_SEGNO_FROM_SEG0(sbi, MAIN_BLKADDR(sbi));
>> free_i->free_segments = 0;
>> @@ -4047,6 +4107,8 @@ static void destroy_free_segmap(struct f2fs_sb_info *sbi)
>> SM_I(sbi)->free_info = NULL;
>> kvfree(free_i->free_segmap);
>> kvfree(free_i->free_secmap);
>> + kvfree(free_i->discard_secmap);
>> + kvfree(free_i->tmp_secmap);
>> kfree(free_i);
>> }
>>
>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>> index 5049551..b37a909 100644
>> --- a/fs/f2fs/segment.h
>> +++ b/fs/f2fs/segment.h
>> @@ -259,6 +259,8 @@ struct free_segmap_info {
>> spinlock_t segmap_lock; /* free segmap lock */
>> unsigned long *free_segmap; /* free segment bitmap */
>> unsigned long *free_secmap; /* free section bitmap */
>> + unsigned long *discard_secmap; /* discard section bitmap */
>> + unsigned long *tmp_secmap; /* bitmap for temporal use */
>> };
>>
>> /* Notice: The order of dirty type is same with CURSEG_XXX in f2fs.h */
>> @@ -453,8 +455,11 @@ static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
>> next = find_next_bit(free_i->free_segmap,
>> start_segno + sbi->segs_per_sec, start_segno);
>> if (next >= start_segno + sbi->segs_per_sec) {
>> - if (test_and_clear_bit(secno, free_i->free_secmap))
>> + if (test_and_clear_bit(secno, free_i->free_secmap)) {
>> free_i->free_sections++;
>> + if (test_opt(sbi, LFS))
>> + clear_bit(secno, free_i->discard_secmap);
>> + }
>> }
>> }
>> skip_free:
>>
>
> .
>
--
Thanks,
Yunlong Song
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