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authorTejun Heo <tj@kernel.org>2012-03-19 15:10:58 -0700
committerJens Axboe <axboe@kernel.dk>2012-03-20 12:47:47 +0100
commit598971bfbdfdc8701337dc1636c7919c44699914 (patch)
tree3de33d5059ce3a0cf77a9735804335f9264b7c08 /include/linux/ioprio.h
parentabede6da27d9bd62ea9512830c83e32b3ee1104c (diff)
cfq: don't use icq_get_changed()
cfq caches the associated cfqq's for a given cic. The cache needs to be flushed if the cic's ioprio or blkcg has changed. It is currently done by requiring the changing action to set the respective ICQ_*_CHANGED bit in the icq and testing it from cfq_set_request(), which involves iterating through all the affected icqs. All cfq wants to know is whether ioprio and/or blkcg have changed since the last flush and can be easily achieved by just remembering the current ioprio and blkcg ID in cic. This patch adds cic->{ioprio|blkcg_id}, updates all ioprio users to use the remembered value instead, and updates cfq_set_request() path such that, instead of using icq_get_changed(), the current values are compared against the remembered ones and trigger appropriate flush action if not. Condition tests are moved inside both _changed functions which are now named check_ioprio_changed() and check_blkcg_changed(). ioprio.h::task_ioprio*() can't be used anymore and replaced with open-coded IOPRIO_CLASS_NONE case in cfq_async_queue_prio(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/ioprio.h')
-rw-r--r--include/linux/ioprio.h22
1 files changed, 5 insertions, 17 deletions
diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h
index 76dad4808847..beb9ce1c2c23 100644
--- a/include/linux/ioprio.h
+++ b/include/linux/ioprio.h
@@ -42,26 +42,14 @@ enum {
};
/*
- * if process has set io priority explicitly, use that. if not, convert
- * the cpu scheduler nice value to an io priority
+ * Fallback BE priority
*/
#define IOPRIO_NORM (4)
-static inline int task_ioprio(struct io_context *ioc)
-{
- if (ioprio_valid(ioc->ioprio))
- return IOPRIO_PRIO_DATA(ioc->ioprio);
-
- return IOPRIO_NORM;
-}
-
-static inline int task_ioprio_class(struct io_context *ioc)
-{
- if (ioprio_valid(ioc->ioprio))
- return IOPRIO_PRIO_CLASS(ioc->ioprio);
-
- return IOPRIO_CLASS_BE;
-}
+/*
+ * if process has set io priority explicitly, use that. if not, convert
+ * the cpu scheduler nice value to an io priority
+ */
static inline int task_nice_ioprio(struct task_struct *task)
{
return (task_nice(task) + 20) / 5;