2014-12-17 10:11:39

by Chao Yu

[permalink] [raw]
Subject: [f2fs-dev][PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

Use more common function ra_meta_pages() with META_POR to readahead node blocks
in restore_node_summary() instead of ra_sum_pages(), hence we can simplify the
readahead code there, and also we can remove unused function ra_sum_pages().

changes from v1:
o fix one bug when using truncate_inode_pages_range which is pointed out by
Jaegeuk Kim.

Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/node.c | 68 +++++++++++++---------------------------------------------
1 file changed, 15 insertions(+), 53 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 5aa54a0..ab48b4c 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1726,80 +1726,42 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
return 0;
}

-/*
- * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-read pages are allocated in bd_inode's mapping tree.
- */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
- int start, int nrpages)
-{
- struct inode *inode = sbi->sb->s_bdev->bd_inode;
- struct address_space *mapping = inode->i_mapping;
- int i, page_idx = start;
- struct f2fs_io_info fio = {
- .type = META,
- .rw = READ_SYNC | REQ_META | REQ_PRIO
- };
-
- for (i = 0; page_idx < start + nrpages; page_idx++, i++) {
- /* alloc page in bd_inode for reading node summary info */
- pages[i] = grab_cache_page(mapping, page_idx);
- if (!pages[i])
- break;
- f2fs_submit_page_mbio(sbi, pages[i], page_idx, &fio);
- }
-
- f2fs_submit_merged_bio(sbi, META, READ);
- return i;
-}
-
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 inode *inode = sbi->sb->s_bdev->bd_inode;
block_t addr;
int bio_blocks = MAX_BIO_BLOCKS(sbi);
- struct page *pages[bio_blocks];
- int i, idx, last_offset, nrpages, err = 0;
+ int i, idx, last_offset, nrpages;

/* scan the node segment */
last_offset = sbi->blocks_per_seg;
addr = START_BLOCK(sbi, segno);
sum_entry = &sum->entries[0];

- for (i = 0; !err && i < last_offset; i += nrpages, addr += nrpages) {
+ for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
nrpages = min(last_offset - i, bio_blocks);

/* readahead node pages */
- nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
- if (!nrpages)
- return -ENOMEM;
+ ra_meta_pages(sbi, addr, nrpages, META_POR);

- for (idx = 0; idx < nrpages; idx++) {
- if (err)
- goto skip;
+ for (idx = addr; idx < addr + nrpages; idx++) {
+ struct page *page = get_meta_page(sbi, idx);

- lock_page(pages[idx]);
- if (unlikely(!PageUptodate(pages[idx]))) {
- err = -EIO;
- } else {
- rn = F2FS_NODE(pages[idx]);
- sum_entry->nid = rn->footer.nid;
- sum_entry->version = 0;
- sum_entry->ofs_in_node = 0;
- sum_entry++;
- }
- unlock_page(pages[idx]);
-skip:
- page_cache_release(pages[idx]);
+ rn = F2FS_NODE(page);
+ sum_entry->nid = rn->footer.nid;
+ sum_entry->version = 0;
+ sum_entry->ofs_in_node = 0;
+ sum_entry++;
+ f2fs_put_page(page, 1);
}

- invalidate_mapping_pages(inode->i_mapping, addr,
- addr + nrpages);
+ truncate_inode_pages_range(META_MAPPING(sbi),
+ addr << PAGE_CACHE_SHIFT,
+ ((addr + nrpages) << PAGE_CACHE_SHIFT) - 1);
}
- return err;
+ return 0;
}

static void remove_nats_in_journal(struct f2fs_sb_info *sbi)
--
2.1.2


2014-12-17 15:20:00

by Changman Lee

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

Hi,

Is there any reason to use truncate_inode_pages_range instead of
invalidate_mapping_pages?
IMHO, it seems nice to just use invalidate_mapping_pages because pages
of meta_inode shouldn't be dirty, locked, under writeback or mapped in
this function.
If there is my misunderstanding, let me know.

Thanks,

Reviewed-by: Changman Lee <[email protected]>

2014-12-17 19:10 GMT+09:00 Chao Yu <[email protected]>:
> Use more common function ra_meta_pages() with META_POR to readahead node blocks
> in restore_node_summary() instead of ra_sum_pages(), hence we can simplify the
> readahead code there, and also we can remove unused function ra_sum_pages().
>
> changes from v1:
> o fix one bug when using truncate_inode_pages_range which is pointed out by
> Jaegeuk Kim.
>
> Signed-off-by: Chao Yu <[email protected]>
> ---
> fs/f2fs/node.c | 68 +++++++++++++---------------------------------------------
> 1 file changed, 15 insertions(+), 53 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 5aa54a0..ab48b4c 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1726,80 +1726,42 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
> return 0;
> }
>
> -/*
> - * ra_sum_pages() merge contiguous pages into one bio and submit.
> - * these pre-read pages are allocated in bd_inode's mapping tree.
> - */
> -static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
> - int start, int nrpages)
> -{
> - struct inode *inode = sbi->sb->s_bdev->bd_inode;
> - struct address_space *mapping = inode->i_mapping;
> - int i, page_idx = start;
> - struct f2fs_io_info fio = {
> - .type = META,
> - .rw = READ_SYNC | REQ_META | REQ_PRIO
> - };
> -
> - for (i = 0; page_idx < start + nrpages; page_idx++, i++) {
> - /* alloc page in bd_inode for reading node summary info */
> - pages[i] = grab_cache_page(mapping, page_idx);
> - if (!pages[i])
> - break;
> - f2fs_submit_page_mbio(sbi, pages[i], page_idx, &fio);
> - }
> -
> - f2fs_submit_merged_bio(sbi, META, READ);
> - return i;
> -}
> -
> 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 inode *inode = sbi->sb->s_bdev->bd_inode;
> block_t addr;
> int bio_blocks = MAX_BIO_BLOCKS(sbi);
> - struct page *pages[bio_blocks];
> - int i, idx, last_offset, nrpages, err = 0;
> + int i, idx, last_offset, nrpages;
>
> /* scan the node segment */
> last_offset = sbi->blocks_per_seg;
> addr = START_BLOCK(sbi, segno);
> sum_entry = &sum->entries[0];
>
> - for (i = 0; !err && i < last_offset; i += nrpages, addr += nrpages) {
> + for (i = 0; i < last_offset; i += nrpages, addr += nrpages) {
> nrpages = min(last_offset - i, bio_blocks);
>
> /* readahead node pages */
> - nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
> - if (!nrpages)
> - return -ENOMEM;
> + ra_meta_pages(sbi, addr, nrpages, META_POR);
>
> - for (idx = 0; idx < nrpages; idx++) {
> - if (err)
> - goto skip;
> + for (idx = addr; idx < addr + nrpages; idx++) {
> + struct page *page = get_meta_page(sbi, idx);
>
> - lock_page(pages[idx]);
> - if (unlikely(!PageUptodate(pages[idx]))) {
> - err = -EIO;
> - } else {
> - rn = F2FS_NODE(pages[idx]);
> - sum_entry->nid = rn->footer.nid;
> - sum_entry->version = 0;
> - sum_entry->ofs_in_node = 0;
> - sum_entry++;
> - }
> - unlock_page(pages[idx]);
> -skip:
> - page_cache_release(pages[idx]);
> + rn = F2FS_NODE(page);
> + sum_entry->nid = rn->footer.nid;
> + sum_entry->version = 0;
> + sum_entry->ofs_in_node = 0;
> + sum_entry++;
> + f2fs_put_page(page, 1);
> }
>
> - invalidate_mapping_pages(inode->i_mapping, addr,
> - addr + nrpages);
> + truncate_inode_pages_range(META_MAPPING(sbi),
> + addr << PAGE_CACHE_SHIFT,
> + ((addr + nrpages) << PAGE_CACHE_SHIFT) - 1);
> }
> - return err;
> + return 0;
> }
>
> static void remove_nats_in_journal(struct f2fs_sb_info *sbi)
> --
> 2.1.2
>
>
>
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2014-12-18 09:26:56

by Chao Yu

[permalink] [raw]
Subject: RE: [f2fs-dev] [PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in restore_node_summary

Hi Changman,

> -----Original Message-----
> From: Changman Lee [mailto:[email protected]]
> Sent: Wednesday, December 17, 2014 11:20 PM
> To: Chao Yu
> Cc: Jaegeuk Kim; Changman Lee; [email protected]; [email protected];
> [email protected]
> Subject: Re: [f2fs-dev] [PATCH v2] f2fs: use ra_meta_pages to simplify readahead code in
> restore_node_summary
>
> Hi,
>
> Is there any reason to use truncate_inode_pages_range instead of
> invalidate_mapping_pages?
> IMHO, it seems nice to just use invalidate_mapping_pages because pages
> of meta_inode shouldn't be dirty, locked, under writeback or mapped in
> this function.
> If there is my misunderstanding, let me know.

I think you're right, I use truncate_inode_pages_range because just following the
usage of readahead-invalidate pair in recovery flow, but without considering the
difference between them.

I will fix this as you suggested.

>
> Thanks,
>
> Reviewed-by: Changman Lee <[email protected]>

And thanks for your review! :)

Regards,
Yu