aboutsummaryrefslogtreecommitdiffstats
path: root/mm
diff options
context:
space:
mode:
authorWu Fengguang <fengguang.wu@intel.com>2010-10-26 17:21:45 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-26 19:52:08 -0400
commit4cbec4c8b9fda9ec784086fe7f74cd32a8adda95 (patch)
tree669c3df27982345b52d0bfca8026e3f275e64a03 /mm
parent0e093d99763eb4cea09f8ca4f1d01f34e121d10b (diff)
writeback: remove the internal 5% low bound on dirty_ratio
The dirty_ratio was silently limited in global_dirty_limits() to >= 5%. This is not a user expected behavior. And it's inconsistent with calc_period_shift(), which uses the plain vm_dirty_ratio value. Let's remove the internal bound. At the same time, fix balance_dirty_pages() to work with the dirty_thresh=0 case. This allows applications to proceed when dirty+writeback pages are all cleaned. And ">" fits with the name "exceeded" better than ">=" does. Neil thinks it is an aesthetic improvement as well as a functional one :) Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Proposed-by: Con Kolivas <kernel@kolivas.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Neil Brown <neilb@suse.de> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michael Rubin <mrubin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page-writeback.c16
1 files changed, 5 insertions, 11 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 4dd91f7fd39f..b840afa89761 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -415,14 +415,8 @@ void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
415 415
416 if (vm_dirty_bytes) 416 if (vm_dirty_bytes)
417 dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE); 417 dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
418 else { 418 else
419 int dirty_ratio; 419 dirty = (vm_dirty_ratio * available_memory) / 100;
420
421 dirty_ratio = vm_dirty_ratio;
422 if (dirty_ratio < 5)
423 dirty_ratio = 5;
424 dirty = (dirty_ratio * available_memory) / 100;
425 }
426 420
427 if (dirty_background_bytes) 421 if (dirty_background_bytes)
428 background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE); 422 background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
@@ -510,7 +504,7 @@ static void balance_dirty_pages(struct address_space *mapping,
510 * catch-up. This avoids (excessively) small writeouts 504 * catch-up. This avoids (excessively) small writeouts
511 * when the bdi limits are ramping up. 505 * when the bdi limits are ramping up.
512 */ 506 */
513 if (nr_reclaimable + nr_writeback < 507 if (nr_reclaimable + nr_writeback <=
514 (background_thresh + dirty_thresh) / 2) 508 (background_thresh + dirty_thresh) / 2)
515 break; 509 break;
516 510
@@ -542,8 +536,8 @@ static void balance_dirty_pages(struct address_space *mapping,
542 * the last resort safeguard. 536 * the last resort safeguard.
543 */ 537 */
544 dirty_exceeded = 538 dirty_exceeded =
545 (bdi_nr_reclaimable + bdi_nr_writeback >= bdi_thresh) 539 (bdi_nr_reclaimable + bdi_nr_writeback > bdi_thresh)
546 || (nr_reclaimable + nr_writeback >= dirty_thresh); 540 || (nr_reclaimable + nr_writeback > dirty_thresh);
547 541
548 if (!dirty_exceeded) 542 if (!dirty_exceeded)
549 break; 543 break;