Hi Jens -

The attached patch speeds it up even more - I'm finding a >9% reduction in %system with no loss in IO performance. This just sets the cached element when the first is looked for.

Alan
From: Alan D. Brunelle <[EMAIL PROTECTED]>

Update cached leftmost every time it is found.

Signed-off-by: Alan D. Brunelle <[EMAIL PROTECTED]>
---

 block/cfq-iosched.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 8093733..a86a7c3 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -388,10 +388,10 @@ cfq_choose_req(struct cfq_data *cfqd, struct request 
*rq1, struct request *rq2)
  */
 static struct rb_node *cfq_rb_first(struct cfq_rb_root *root)
 {
-       if (root->left)
-               return root->left;
+       if (!root->left)
+               root->left = rb_first(&root->rb);
 
-       return rb_first(&root->rb);
+       return root->left;
 }
 
 static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)

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