OGAWA Hirofumi <hirof...@mail.parknet.co.jp> writes: > Fengguang Wu <fengguang...@intel.com> writes: > >> On Wed, Sep 12, 2012 at 03:28:42AM +0900, OGAWA Hirofumi wrote: >>> >>> If bdi has BDI_CAP_NO_WRITEBACK, bdi_forker_thread() doesn't start >>> writeback thread. This means there is no consumer of work item made >>> by bdi_queue_work(). >>> >>> This adds to checking of !bdi_cap_writeback_dirty(sb->s_bdi) before >>> calling bdi_queue_work(), otherwise queued work never be consumed. >>> >>> Signed-off-by: OGAWA Hirofumi <hirof...@mail.parknet.co.jp> >>> --- >>> >>> fs/fs-writeback.c | 7 +++++-- >>> 1 file changed, 5 insertions(+), 2 deletions(-) >>> >>> diff -puN fs/fs-writeback.c~noop_backing_dev_info-check-fix >>> fs/fs-writeback.c >>> --- linux/fs/fs-writeback.c~noop_backing_dev_info-check-fix 2012-09-11 >>> 06:12:30.000000000 +0900 >>> +++ linux-hirofumi/fs/fs-writeback.c 2012-09-11 06:12:30.000000000 >>> +0900 >>> @@ -120,6 +120,9 @@ __bdi_start_writeback(struct backing_dev >>> { >>> struct wb_writeback_work *work; >>> >>> + if (!bdi_cap_writeback_dirty(bdi)) >>> + return; >> >> Will someone in the current kernel actually call >> __bdi_start_writeback() on a BDI_CAP_NO_WRITEBACK bdi? >> >> If the answer is no, VM_BUG_ON(!bdi_cap_writeback_dirty(bdi)) looks better. > > I guess nobody call it in current kernel though. Hmm.., but we also have > check in __mark_inode_dirty(), nobody should be using it, right? > > If we defined it as the bug, I can't see what BDI_CAP_NO_WRITEBACK wants > to do actually. We are not going to allow to disable the writeback task?
ping. You are saying we should change bdi_cap_writeback_dirty(bdi) to VM_BUG_ON() too in __mark_inode_dirty()? And probably, you are going to remove the usage of BDI_CAP_NO_WRITEBACK for sb->s_bdi? > I was going to use this to disable writeback task on my developing FS... -- OGAWA Hirofumi <hirof...@mail.parknet.co.jp> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/