Messages in this thread | | | Date | Mon, 15 Oct 2018 20:10:52 -0700 | From | Jaegeuk Kim <> | Subject | Re: [f2fs-dev] [PATCH] f2fs: clear cold data flag if IO is not counted |
| |
On 10/16, Chao Yu wrote: > 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:
Well, wait_on_stable_page() doesn't guarantee its end_io. So, I'm not sure this is the only case.
> > 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); > >>> > > > > . > >
| |