Hi, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] > Sent: Monday, December 09, 2013 4:01 PM > To: Chao Yu > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [f2fs-dev] [PATCH 3/3 V3] f2fs: introduce f2fs_cache_node_page() to add page into node_inode cache > > Hi, > > Sorry for the noise. > Once I tested this patch, I recognized that I made a mistake: > > f2fs_fill_super() > 1. build_segment_manager() > -> restore_node_summary() > -> NULL pointer exception, due to no NAT cache. > 2. build_node_manager() > > So, we should not call get_node_info() prior to build_node_manager(). > And, it's not easy to change the order of build_*_manager simply. > > Let's consider in more details. Before we call restore_node_summary(), we have read HOT_DATA Summary. It means already we got the NAT cache in curseg. Although we could not call get_node_info() directly, we still could use NAT cache in HOT_DATA curseg. So how about using this cache to verify validity of page like this? f2fs_cache_node_page() if(!looup_nat_curseg_cache()) return; grab_cache_page(); memcpy(); SetPageUptodate(); f2fs_put_page(); > Thanks, > > 2013-12-09 (월), 13:35 +0800, Chao Yu: > > This patch introduces f2fs_cache_node_page(), in this function, page which is > > readed ahead will be copy to node_inode's mapping cache. > > It will avoid rereading these node pages. > > > > change log: > > o check validity of page by searching NAT suggested by Jaegeuk Kim. > > o add 'unlikely' for compiler optimization suggested by Jaegeuk Kim. > > > > Suggested-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> > > --- > > fs/f2fs/node.c | 39 ++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 38 insertions(+), 1 deletion(-) > > > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > index 099f06f..4c6da98 100644 > > --- a/fs/f2fs/node.c > > +++ b/fs/f2fs/node.c > > @@ -1600,13 +1600,46 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, > > return 0; > > } > > > > +/* > > + * f2fs_cache_node_page() check validaty of input page by searching NAT. > > + * Then, it will copy updated data of vaild page to node_inode cache. > > + */ > > +void f2fs_cache_node_page(struct f2fs_sb_info *sbi, struct page *page, > > + nid_t nid, block_t blkaddr) > > +{ > > + struct address_space *mapping = sbi->node_inode->i_mapping; > > + struct page *npage; > > + struct node_info ni; > > + > > + get_node_info(sbi, nid, &ni); > > + > > + if (ni.blk_addr != blkaddr) > > + return; > > + > > + npage = grab_cache_page(mapping, nid); > > + if (unlikely(!npage)) > > + return; > > + > > + if (PageUptodate(npage)) { > > + f2fs_put_page(npage, 1); > > + return; > > + } > > + > > + memcpy(page_address(npage), page_address(page), PAGE_CACHE_SIZE); > > + > > + SetPageUptodate(npage); > > + f2fs_put_page(npage, 1); > > + > > + return; > > +} > > + > > int restore_node_summary(struct f2fs_sb_info *sbi, > > unsigned int segno, struct f2fs_summary_block *sum) > > { > > struct f2fs_node *rn; > > struct f2fs_summary *sum_entry; > > struct page *page, *tmp; > > - block_t addr; > > + block_t addr, blkaddr; > > int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi)); > > int i, last_offset, nrpages, err = 0; > > LIST_HEAD(page_list); > > @@ -1624,6 +1657,7 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > if (err) > > return err; > > > > + blkaddr = addr; > > list_for_each_entry_safe(page, tmp, &page_list, lru) { > > > > lock_page(page); > > @@ -1633,6 +1667,8 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > sum_entry->version = 0; > > sum_entry->ofs_in_node = 0; > > sum_entry++; > > + f2fs_cache_node_page(sbi, page, > > + le32_to_cpu(rn->footer.nid), blkaddr); > > } else { > > err = -EIO; > > } > > @@ -1640,6 +1676,7 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > list_del(&page->lru); > > unlock_page(page); > > __free_pages(page, 0); > > + blkaddr++; > > } > > } > > return err; > > -- > Jaegeuk Kim > Samsung -- 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
