lkml.org 
[lkml]   [2020]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/1] kernel/sched:use the enum code replace of the int variable
Date
From: jun qian <qianjun.kernel@gmail.com>

It is hard to understand what the meaning of the value from
the return value of wakeup_preempt_entity, so I fix it.

Signed-off-by: jun qian <qianjun.kernel@gmail.com>
---
kernel/sched/fair.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 658aa7a..60bb184 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -86,6 +86,12 @@

const_debug unsigned int sysctl_sched_migration_cost = 500000UL;

+enum preempt_curr_code {
+ NO_NEED_PREEMPT = -1,
+ MAY_NEED_PREEMPT = 0,
+ NEED_PREEMPT = 1,
+};
+
int sched_thermal_decay_shift;
static int __init setup_sched_thermal_decay_shift(char *str)
{
@@ -4445,20 +4451,20 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
second = curr;
}

- if (second && wakeup_preempt_entity(second, left) < 1)
+ if (second && wakeup_preempt_entity(second, left) != NEED_PREEMPT)
se = second;
}

/*
* Prefer last buddy, try to return the CPU to a preempted task.
*/
- if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
+ if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) != NEED_PREEMPT)
se = cfs_rq->last;

/*
* Someone really wants this to run. If it's not unfair, run it.
*/
- if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
+ if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) != NEED_PREEMPT)
se = cfs_rq->next;

clear_buddies(cfs_rq, se);
@@ -6822,9 +6828,9 @@ static unsigned long wakeup_gran(struct sched_entity *se)
* g
* |<--->|c
*
- * w(c, s1) = -1
- * w(c, s2) = 0
- * w(c, s3) = 1
+ * w(c, s1) = NO_NEED_PREEMPT
+ * w(c, s2) = MAY_NEED_PREEMPT
+ * w(c, s3) = NEED_PREEMPT
*
*/
static int
@@ -6833,13 +6839,13 @@ static unsigned long wakeup_gran(struct sched_entity *se)
s64 gran, vdiff = curr->vruntime - se->vruntime;

if (vdiff <= 0)
- return -1;
+ return NO_NEED_PREEMPT;

gran = wakeup_gran(se);
if (vdiff > gran)
- return 1;
+ return NEED_PREEMPT;

- return 0;
+ return MAY_NEED_PREEMPT;
}

static void set_last_buddy(struct sched_entity *se)
@@ -6928,7 +6934,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
find_matching_se(&se, &pse);
update_curr(cfs_rq_of(se));
BUG_ON(!pse);
- if (wakeup_preempt_entity(se, pse) == 1) {
+ if (wakeup_preempt_entity(se, pse) == NEED_PREEMPT) {
/*
* Bias pick_next to pick the sched entity that is
* triggering this preemption.
--
1.8.3.1
\
 
 \ /
  Last update: 2020-09-07 15:08    [W:0.050 / U:2.368 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site