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page-writeback: fix the calculation of the oldest_jif in wb_kupdate()

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wb_kupdate() function has a bug on linux-2.6.30-rc5.  This bug causes
generic_sync_sb_inodes() to start to write inodes back much earlier than
our expectations because it miscalculates oldest_jif in wb_kupdate().

This bug was introduced in 704503d836
('mm: fix proc_dointvec_userhz_jiffies "breakage"').

Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Toshiyuki Okajima
2009-05-16 22:56:28 -07:00
committed by Linus Torvalds
parent cd208bcc7c
commit 22ef37eed6
1 changed files with 3 additions and 3 deletions
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6
mm/page-writeback.c
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@@ -94,12 +94,12 @@ unsigned long vm_dirty_bytes;
/* /*
* The interval between `kupdate'-style writebacks * The interval between `kupdate'-style writebacks
*/ */
unsigned int dirty_writeback_interval = 5 * 100; /* sentiseconds */ unsigned int dirty_writeback_interval = 5 * 100; /* centiseconds */
/* /*
* The longest time for which data is allowed to remain dirty * The longest time for which data is allowed to remain dirty
*/ */
unsigned int dirty_expire_interval = 30 * 100; /* sentiseconds */ unsigned int dirty_expire_interval = 30 * 100; /* centiseconds */
/* /*
* Flag that makes the machine dump writes/reads and block dirtyings. * Flag that makes the machine dump writes/reads and block dirtyings.
@@ -770,7 +770,7 @@ static void wb_kupdate(unsigned long arg)
sync_supers(); sync_supers();
oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval); oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval * 10);
start_jif = jiffies; start_jif = jiffies;
next_jif = start_jif + msecs_to_jiffies(dirty_writeback_interval * 10); next_jif = start_jif + msecs_to_jiffies(dirty_writeback_interval * 10);
nr_to_write = global_page_state(NR_FILE_DIRTY) + nr_to_write = global_page_state(NR_FILE_DIRTY) +