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SubjectRe: [f2fs-dev] [PATCH 1/3] f2fs: use f2fs_submit_page_bio for ra_meta_pages
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On 2017/5/11 10:41, Jaegeuk Kim wrote:
> On 05/11, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> On 2017/5/11 7:48, Jaegeuk Kim wrote:
>>> This patch avoids to use f2fs_submit_merged_bio for read, which was the only
>>> read case.
>>
>> This makes f2fs losing the chance to merge multiple pages into one bio during
>> reading continuous physical blocks, it may cause potential performance
>> regression, how about using a local bio in ra_meta_pages to cache more pages?
>
> This is a readahead flow, which is asynchronous and not a performance critical
> flow. And, I expect blk_plug is still able to merge them. We're using this in
> readahead of node blocks as well.

Confirmed, block plug can do the merge. :)

Thanks,

>
> Thanks,
>
>>
>> Thanks,
>>
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
>>> ---
>>> fs/f2fs/checkpoint.c | 4 +---
>>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>> index ea9c317b5916..8d92f8249000 100644
>>> --- a/fs/f2fs/checkpoint.c
>>> +++ b/fs/f2fs/checkpoint.c
>>> @@ -207,12 +207,10 @@ int ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
>>> }
>>>
>>> fio.page = page;
>>> - fio.old_blkaddr = fio.new_blkaddr;
>>> - f2fs_submit_page_mbio(&fio);
>>> + f2fs_submit_page_bio(&fio);
>>> f2fs_put_page(page, 0);
>>> }
>>> out:
>>> - f2fs_submit_merged_bio(sbi, META, READ);
>>> blk_finish_plug(&plug);
>>> return blkno - start;
>>> }
>>>
>
> .
>

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