page-writeback: fix the calculation of the oldest_jif in wb_kupdate() (22ef37ee) · Commits · 戴 / test

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 ('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>

mm/page-writeback.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -94,12 +94,12 @@ unsigned long vm_dirty_bytes;
		/*
		* 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
		*/
		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.
		@@ -770,7 +770,7 @@ static void wb_kupdate(unsigned long arg)

		sync_supers();

		oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval);
		oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval * 10);
		start_jif = jiffies;
		next_jif = start_jif + msecs_to_jiffies(dirty_writeback_interval * 10);
		nr_to_write = global_page_state(NR_FILE_DIRTY) +

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