Hi Gu, > -----Original Message----- > From: Gu Zheng [mailto:guz.fnst@xxxxxxxxxxxxxx] > Sent: Monday, November 18, 2013 7:16 PM > To: Chao Yu > Cc: '???'; linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; 谭姝 > Subject: Re: [f2fs-dev] [PATCH V2 2/2] f2fs: read contiguous sit entry pages by merging for mount performance > > Hi Yu, > One more comment, please refer to inline. > On 11/16/2013 02:15 PM, Chao Yu wrote: > > > Previously we read sit entries page one by one, this method lost the chance of reading contiguous page together. > > So we read pages as contiguous as possible for better mount performance. > > > > v1-->v2: > > o merge judgements/use 'Continue' or 'Break' instead of 'Goto' as Gu Zheng suggested. > > o add mark_page_accessed () before release page to delay VM reclaiming them. > > > > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> > > --- > > fs/f2fs/segment.c | 108 ++++++++++++++++++++++++++++++++++++++++------------- > > fs/f2fs/segment.h | 2 + > > 2 files changed, 84 insertions(+), 26 deletions(-) > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > index fa284d3..656fe40 100644 > > --- a/fs/f2fs/segment.c > > +++ b/fs/f2fs/segment.c > > @@ -14,6 +14,7 @@ > > #include <linux/blkdev.h> > > #include <linux/prefetch.h> > > #include <linux/vmalloc.h> > > +#include <linux/swap.h> > > > > #include "f2fs.h" > > #include "segment.h" > > @@ -1480,41 +1481,96 @@ static int build_curseg(struct f2fs_sb_info *sbi) > > return restore_curseg_summaries(sbi); > > } > > > > +static int ra_sit_pages(struct f2fs_sb_info *sbi, int start, > > + int nrpages, bool *is_order) > > +{ > > + struct address_space *mapping = sbi->meta_inode->i_mapping; > > + struct sit_info *sit_i = SIT_I(sbi); > > + struct page *page; > > + block_t blk_addr; > > + int blkno = start, readcnt = 0; > > + int sit_blk_cnt = SIT_BLK_CNT(sbi); > > + > > + for (; blkno < start + nrpages && blkno < sit_blk_cnt; blkno++) { > > + > > + if ((!f2fs_test_bit(blkno, sit_i->sit_bitmap) ^ !*is_order)) { > > + *is_order = !*is_order; > > + break; > > + } > > + > > + blk_addr = sit_i->sit_base_addr + blkno; > > + if (*is_order) > > + blk_addr += sit_i->sit_blocks; > > +repeat: > > + page = grab_cache_page(mapping, blk_addr); > > + if (!page) { > > + cond_resched(); > > + goto repeat; > > + } > > + if (PageUptodate(page)) { > > + mark_page_accessed(page); > > + f2fs_put_page(page, 1); > > + readcnt++; > > + continue; > > + } > > + > > + submit_read_page(sbi, page, blk_addr, READ_SYNC); > > + > > + mark_page_accessed(page); > > + f2fs_put_page(page, 0); > > + readcnt++; > > + } > > + > > + f2fs_submit_read_bio(sbi, READ_SYNC); > > + return readcnt; > > +} > > + > > static void build_sit_entries(struct f2fs_sb_info *sbi) > > { > > struct sit_info *sit_i = SIT_I(sbi); > > struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA); > > struct f2fs_summary_block *sum = curseg->sum_blk; > > - unsigned int start; > > - > > - for (start = 0; start < TOTAL_SEGS(sbi); start++) { > > - struct seg_entry *se = &sit_i->sentries[start]; > > - struct f2fs_sit_block *sit_blk; > > - struct f2fs_sit_entry sit; > > - struct page *page; > > - int i; > > + bool is_order = f2fs_test_bit(0, sit_i->sit_bitmap) ? true : false; > > + int sit_blk_cnt = SIT_BLK_CNT(sbi); > > + unsigned int i, start, end; > > + unsigned int readed, start_blk = 0; > > > > - mutex_lock(&curseg->curseg_mutex); > > - for (i = 0; i < sits_in_cursum(sum); i++) { > > - if (le32_to_cpu(segno_in_journal(sum, i)) == start) { > > - sit = sit_in_journal(sum, i); > > - mutex_unlock(&curseg->curseg_mutex); > > - goto got_it; > > + do { > > How about using find_next_bit to get the suitable start_blk if the next blk > is not ordered here? And it also can simplify the logic of ra_sit_pages(). That's a good idea. But I thought there maybe endianness problem between test_bit and f2fs_test_bit, so find_next_bit may get wrong result. Am I right? Thanks, Yu > > Thanks, > Gu > > > + readed = ra_sit_pages(sbi, start_blk, sit_blk_cnt, &is_order); > > + > > + start = start_blk * sit_i->sents_per_block; > > + end = (start_blk + readed) * sit_i->sents_per_block; > > + > > + for (; start < end && start < TOTAL_SEGS(sbi); start++) { > > + struct seg_entry *se = &sit_i->sentries[start]; > > + struct f2fs_sit_block *sit_blk; > > + struct f2fs_sit_entry sit; > > + struct page *page; > > + > > + mutex_lock(&curseg->curseg_mutex); > > + for (i = 0; i < sits_in_cursum(sum); i++) { > > + if (le32_to_cpu(segno_in_journal(sum, i)) == start) { > > + sit = sit_in_journal(sum, i); > > + mutex_unlock(&curseg->curseg_mutex); > > + goto got_it; > > + } > > } > > - } > > - mutex_unlock(&curseg->curseg_mutex); > > - page = get_current_sit_page(sbi, start); > > - sit_blk = (struct f2fs_sit_block *)page_address(page); > > - sit = sit_blk->entries[SIT_ENTRY_OFFSET(sit_i, start)]; > > - f2fs_put_page(page, 1); > > + mutex_unlock(&curseg->curseg_mutex); > > + > > + page = get_current_sit_page(sbi, start); > > + sit_blk = (struct f2fs_sit_block *)page_address(page); > > + sit = sit_blk->entries[SIT_ENTRY_OFFSET(sit_i, start)]; > > + f2fs_put_page(page, 1); > > got_it: > > - check_block_count(sbi, start, &sit); > > - seg_info_from_raw_sit(se, &sit); > > - if (sbi->segs_per_sec > 1) { > > - struct sec_entry *e = get_sec_entry(sbi, start); > > - e->valid_blocks += se->valid_blocks; > > + check_block_count(sbi, start, &sit); > > + seg_info_from_raw_sit(se, &sit); > > + if (sbi->segs_per_sec > 1) { > > + struct sec_entry *e = get_sec_entry(sbi, start); > > + e->valid_blocks += se->valid_blocks; > > + } > > } > > - } > > + start_blk += readed; > > > > > > + } while (start_blk < sit_blk_cnt); > > } > > > > static void init_free_segmap(struct f2fs_sb_info *sbi) > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > > index 269f690..ad5b9f1 100644 > > --- a/fs/f2fs/segment.h > > +++ b/fs/f2fs/segment.h > > @@ -83,6 +83,8 @@ > > (segno / SIT_ENTRY_PER_BLOCK) > > #define START_SEGNO(sit_i, segno) \ > > (SIT_BLOCK_OFFSET(sit_i, segno) * SIT_ENTRY_PER_BLOCK) > > +#define SIT_BLK_CNT(sbi) \ > > + ((TOTAL_SEGS(sbi) + SIT_ENTRY_PER_BLOCK - 1) / SIT_ENTRY_PER_BLOCK) > > #define f2fs_bitmap_size(nr) \ > > (BITS_TO_LONGS(nr) * sizeof(unsigned long)) > > #define TOTAL_SEGS(sbi) (SM_I(sbi)->main_segments) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
