[Devel] [PATCH RHEL7 COMMIT] Revert diff-writeback-throttle-writer-when-local-BDI-threshold-is-hit bits

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-229.7.2-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.6.6
------>
commit 56782e5a6d798078f3523e97f6f2eb8277028b91
Author: Vladimir Davydov <vdavydov at parallels.com>
Date:   Thu Sep 3 13:53:01 2015 +0400

    Revert diff-writeback-throttle-writer-when-local-BDI-threshold-is-hit bits
    
    This was brought by the initial commit 2a8b5de95918, but it is
    incomplete - the following hunk patching balance_dirty_pages was lost:
    
    > diff --git a/mm/page-writeback.c b/mm/page-writeback.c
    > index 003b68e..a58795c 100644
    > --- a/mm/page-writeback.c
    > +++ b/mm/page-writeback.c
    > @@ -546,7 +546,8 @@ static void balance_dirty_pages(struct address_space *mapping,
    >                * catch-up. This avoids (excessively) small writeouts
    >                * when the bdi limits are ramping up.
    >                */
    > -             if (nr_reclaimable + nr_writeback <
    > +             if (bdi_cap_account_writeback(bdi) &&
    > +                 nr_reclaimable + nr_writeback <
    >                               (background_thresh + dirty_thresh) / 2 &&
    >                   ub_dirty + ub_writeback <
    >                               (ub_background_thresh + ub_thresh) / 2)
    
    I've filed a separate issue for porting it:
    
    https://jira.sw.ru/browse/PSBM-39167
    
    Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
---
 fs/fs-writeback.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 9cdcc28..66586a4 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -843,9 +843,6 @@ static bool over_bground_thresh(struct backing_dev_info *bdi)
 {
 	unsigned long background_thresh, dirty_thresh;
 
-	if (!bdi_cap_account_writeback(bdi) && bdi->dirty_exceeded)
-		return true;
-
 	global_dirty_limits(&background_thresh, &dirty_thresh);
 
 	if (global_page_state(NR_FILE_DIRTY) +