On Fri, 20 Apr 2007 17:52:02 +0200 Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> Count per BDI writeback pages. > > Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]> > --- > include/linux/backing-dev.h | 1 + > mm/page-writeback.c | 12 ++++++++++-- > 2 files changed, 11 insertions(+), 2 deletions(-) > > Index: linux-2.6/mm/page-writeback.c > =================================================================== > --- linux-2.6.orig/mm/page-writeback.c 2007-04-20 15:27:28.000000000 > +0200 > +++ linux-2.6/mm/page-writeback.c 2007-04-20 15:28:10.000000000 +0200 > @@ -979,14 +979,18 @@ int test_clear_page_writeback(struct pag > int ret; > > if (mapping) { > + struct backing_dev_info *bdi = mapping->backing_dev_info; > unsigned long flags; > > write_lock_irqsave(&mapping->tree_lock, flags); > ret = TestClearPageWriteback(page); > - if (ret) > + if (ret) { > radix_tree_tag_clear(&mapping->page_tree, > page_index(page), > PAGECACHE_TAG_WRITEBACK); > + if (bdi_cap_writeback_dirty(bdi)) > + __dec_bdi_stat(bdi, BDI_WRITEBACK); Why do we test bdi_cap_writeback_dirty() here? If we remove that test, we end up accumulating statistics for non-writebackable backing devs, but does that matter? Probably the common case is writebackable backing-devs, so eliminating the test-n-branch might be a net microgain. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/