From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH 02/11] readahead: bump up the default readahead size Date: Tue, 02 Feb 2010 23:28:37 +0800 Message-ID: <20100202153316.513043033@intel.com> References: <20100202152835.683907822@intel.com> Cc: Jens Axboe , Peter Zijlstra , Martin Schwidefsky , Christian Ehrhardt , Wu Fengguang To: Andrew Morton Return-path: cc: Linux Memory Management List cc: Cc: LKML Content-Disposition: inline; filename=readahead-enlarge-default-size.patch Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org Use 512kb max readahead size, and 32kb min readahead size. The former helps io performance for common workloads. The latter will be used in the thrashing safe context readahead. CC: Jens Axboe CC: Peter Zijlstra CC: Martin Schwidefsky CC: Christian Ehrhardt Signed-off-by: Wu Fengguang --- include/linux/mm.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- linux.orig/include/linux/mm.h 2010-01-30 17:38:49.000000000 +0800 +++ linux/include/linux/mm.h 2010-01-30 18:09:58.000000000 +0800 @@ -1184,8 +1184,8 @@ int write_one_page(struct page *page, in void task_dirty_inc(struct task_struct *tsk); /* readahead.c */ -#define VM_MAX_READAHEAD 128 /* kbytes */ -#define VM_MIN_READAHEAD 16 /* kbytes (includes current page) */ +#define VM_MAX_READAHEAD 512 /* kbytes */ +#define VM_MIN_READAHEAD 32 /* kbytes (includes current page) */ int force_page_cache_readahead(struct address_space *mapping, struct file *filp, pgoff_t offset, unsigned long nr_to_read); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org