linux-kernel - [PATCH] fix task dirty balancing

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Date:	Wed,  2 Jul 2008 17:26:44 +0900 (JST)
From:	yamamoto@...inux.co.jp (YAMAMOTO Takashi)
To:	a.p.zijlstra@...llo.nl
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] fix task dirty balancing

hi,

task_dirty_inc doesn't seem to be called properly for
filesystems which don't use set_page_dirty for write(2).
eg. ext2 w/o nobh option.

YAMAMOTO Takashi


Signed-off-by: YAMAMOTO Takashi <yamamoto@...inux.co.jp>
---

commit e68f05bf56d0652c107bba1cff3f8491e41a2117
Author: YAMAMOTO Takashi <yamamoto@...inux.co.jp>
Date:   Wed Jul 2 16:17:33 2008 +0900

    fix dirty balancing for tasks.
    
    call task_dirty_inc when dirtying a page with mark_buffer_dirty.

diff --git a/fs/buffer.c b/fs/buffer.c
index 4788a9e..2f1c7c6 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1219,8 +1219,9 @@ void mark_buffer_dirty(struct buffer_head *bh)
 			return;
 	}
 
-	if (!test_set_buffer_dirty(bh))
-		__set_page_dirty(bh->b_page, page_mapping(bh->b_page), 0);
+	if (!test_set_buffer_dirty(bh) &&
+	    __set_page_dirty(bh->b_page, page_mapping(bh->b_page), 0))
+		task_dirty_inc(current);
 }
 
 /*
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index bd91987..61d0aec 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -95,6 +95,7 @@ int wakeup_pdflush(long nr_pages);
 void laptop_io_completion(void);
 void laptop_sync_completion(void);
 void throttle_vm_writeout(gfp_t gfp_mask);
+void task_dirty_inc(struct task_struct *);
 
 /* These are exported to sysctl. */
 extern int dirty_background_ratio;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 29b1d1e..4dc85d0 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -176,10 +176,11 @@ void bdi_writeout_inc(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL_GPL(bdi_writeout_inc);
 
-static inline void task_dirty_inc(struct task_struct *tsk)
+void task_dirty_inc(struct task_struct *tsk)
 {
 	prop_inc_single(&vm_dirties, &tsk->dirties);
 }
+EXPORT_SYMBOL_GPL(task_dirty_inc);
 
 /*
  * Obtain an accurate fraction of the BDI's portion.
--
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