Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH] f2fs: clear cold data flag if IO is not counted | From | Chao Yu <> | Date | Tue, 16 Oct 2018 09:31:25 +0800 |
| |
On 2018/10/16 7:08, Jaegeuk Kim wrote: > On 10/15, Chao Yu wrote: >> On 2018/10/11 5:22, Jaegeuk Kim wrote: >>> If we clear the cold data flag out of the writeback flow, we can miscount >>> -1 by end_io. >> >> I didn't get it, which count do you mean? > > It's the number of dirty pages. > > Balancing F2FS Async: > - IO (CP: 1, Data: -1, Flush: ( 0 0 1), Discard: ( 0 129304)) cmd: 0 undiscard: 0 >
So I guess the race should be:
GC thread: IRQ - move_data_page() - set_page_dirty() - clear_cold_data() - f2fs_write_end_io() - type = WB_DATA_TYPE(page); here, we get wrong type - dec_page_count(sbi, type); - f2fs_wait_on_page_writeback()
How about relocate wait_writeback & set_page_dirty to avoid above race:
move_data_page()
retry: f2fs_wait_on_page_writeback(page, DATA, true); set_page_dirty(page);
Thanks,
>> >> Thanks, >> >>> >>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> >>> --- >>> fs/f2fs/data.c | 4 ---- >>> 1 file changed, 4 deletions(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 29a9d3b8f709..4102799b5558 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -2636,10 +2636,6 @@ static int f2fs_set_data_page_dirty(struct page *page) >>> if (!PageUptodate(page)) >>> SetPageUptodate(page); >>> >>> - /* don't remain PG_checked flag which was set during GC */ >>> - if (is_cold_data(page)) >>> - clear_cold_data(page); >>> - >>> if (f2fs_is_atomic_file(inode) && !f2fs_is_commit_atomic_write(inode)) { >>> if (!IS_ATOMIC_WRITTEN_PAGE(page)) { >>> f2fs_register_inmem_page(inode, page); >>> > > . >
| |