Commit 4a21aef4 authored Nov 02, 2016 by Bobi Jam Committed by Greg Kroah-Hartman Nov 07, 2016

staging/lustre/llite: update ras window correctly



When stride-RA hit case miss, we only reset normal sequential
read-ahead window, but not reset the stride IO to avoid the overhead
of re-detecting stride IO. While when the normal RA window is set
to not insect with the stride-RA window, when we try to increase
the stride-RA window length later, the presumption does not hold.

This patch resets the stride IO as well in this case.

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Reviewed-on: http://review.whamcloud.com/23032
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8683


Reviewed-by: wangdi <di.wang@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 9cc58f1e

drivers/staging/lustre/lustre/llite/rw.c

+11 −4

Original line number	Diff line number	Diff line
		@@ -809,13 +809,20 @@ static void ras_update(struct ll_sb_info sbi, struct inode inode,
		if (ra_miss) {
		if (index_in_stride_window(ras, index) &&
		stride_io_mode(ras)) {
		/*If stride-RA hit cache miss, the stride dector
		*will not be reset to avoid the overhead of
		*redetecting read-ahead mode
		*/
		if (index != ras->ras_last_readpage + 1)
		ras->ras_consecutive_pages = 0;
		ras_reset(inode, ras, index);

		/* If stride-RA hit cache miss, the stride
		* detector will not be reset to avoid the
		* overhead of redetecting read-ahead mode,
		* but on the condition that the stride window
		* is still intersect with normal sequential
		* read-ahead window.
		*/
		if (ras->ras_window_start <
		ras->ras_stride_offset)
		ras_stride_reset(ras);
		RAS_CDEBUG(ras);
		} else {
		/* Reset both stride window and normal RA