From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Jason Baron <jbaron@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Paul Turner <pjt@google.com>,
linux-kernel@vger.kernel.org,
Bharata B Rao <bharata@linux.vnet.ibm.com>,
Dhaval Giani <dhaval.giani@gmail.com>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Pavel Emelyanov <xemul@openvz.org>, Hu Tao <hutao@cn.fujitsu.com>,
Mike Galbraith <efault@gmx.de>
Subject: jump_label defaults (was Re: [patch 00/17] CFS Bandwidth Control v7.1)
Date: Thu, 07 Jul 2011 22:36:14 +0200 [thread overview]
Message-ID: <1310070974.3282.678.camel@twins> (raw)
In-Reply-To: <20110707181535.GD2536@redhat.com>
[resend because I somehow managed to wreck the lkml address]
On Thu, 2011-07-07 at 14:15 -0400, Jason Baron wrote:
> We don't have to wait until jump_label_init() to make it take effect.
>
> We could introduce something like: static_branch_default_false(&foo),
> and static_branch_default_true(&foo), which are set at compile time. I
> was waiting for a real world example before introducing it, but if this
> would solve your issue, we can look at it.
Hrm,. I can't seem to make that work, damn CPP for not being recursive.
The thing in question is the below patch, I'd need something like:
sed -ie 's/1)/true)' -e 's/0)/false)/' kernel/sched_features.h
#define SCHED_FEAT(name, enabled) \
#define static_branch_##name static_branch_default_##enabled
#include "sched_features.h"
#undef SCHED_FEAT
so that I can then do:
#define sched_feat(x) \
static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
Otherwise there's no way to get the default thing related to x.
Also, it still needs an initializer for jump_label_key to get in the
correct state.
---
Subject: sched: Use jump_labels for sched_feat
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Wed Jul 06 14:20:14 CEST 2011
static_branch() is disabled by default, but more sched_feat are enabled
by default, so invert the logic. Fixup the few stragglers on
late_initcall().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-10afjk8n3eu30jytrhdpaluc@git.kernel.org
---
kernel/sched.c | 33 ++++++++++++++++++++++++++-------
1 file changed, 26 insertions(+), 7 deletions(-)
Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -71,6 +71,7 @@
#include <linux/ctype.h>
#include <linux/ftrace.h>
#include <linux/slab.h>
+#include <linux/jump_label.h>
#include <asm/tlb.h>
#include <asm/irq_regs.h>
@@ -691,6 +692,7 @@ int runqueue_is_locked(int cpu)
enum {
#include "sched_features.h"
+ __SCHED_FEAT_NR
};
#undef SCHED_FEAT
@@ -710,16 +712,17 @@ const_debug unsigned int sysctl_sched_fe
static __read_mostly char *sched_feat_names[] = {
#include "sched_features.h"
- NULL
};
#undef SCHED_FEAT
+static struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR];
+
static int sched_feat_show(struct seq_file *m, void *v)
{
int i;
- for (i = 0; sched_feat_names[i]; i++) {
+ for (i = 0; i < __SCHED_FEAT_NR; i++) {
if (!(sysctl_sched_features & (1UL << i)))
seq_puts(m, "NO_");
seq_printf(m, "%s ", sched_feat_names[i]);
@@ -752,17 +755,22 @@ sched_feat_write(struct file *filp, cons
cmp += 3;
}
- for (i = 0; sched_feat_names[i]; i++) {
+ for (i = 0; i < __SCHED_FEAT_NR; i++) {
if (strcmp(cmp, sched_feat_names[i]) == 0) {
- if (neg)
+ if (neg) {
sysctl_sched_features &= ~(1UL << i);
- else
+ if (!jump_label_enabled(&sched_feat_keys[i]))
+ jump_label_inc(&sched_feat_keys[i]);
+ } else {
sysctl_sched_features |= (1UL << i);
+ if (jump_label_enabled(&sched_feat_keys[i]))
+ jump_label_dec(&sched_feat_keys[i]);
+ }
break;
}
}
- if (!sched_feat_names[i])
+ if (i == __SCHED_FEAT_NR)
return -EINVAL;
*ppos += cnt;
@@ -785,6 +793,13 @@ static const struct file_operations sche
static __init int sched_init_debug(void)
{
+ int i;
+
+ for (i = 0; i < __SCHED_FEAT_NR; i++) {
+ if (!(sysctl_sched_features & (1UL << i)))
+ jump_label_inc(&sched_feat_keys[i]);
+ }
+
debugfs_create_file("sched_features", 0644, NULL, NULL,
&sched_feat_fops);
@@ -792,10 +807,14 @@ static __init int sched_init_debug(void)
}
late_initcall(sched_init_debug);
-#endif
+#define sched_feat(x) (!static_branch(&sched_feat_keys[__SCHED_FEAT_##x]))
+
+#else /* CONFIG_SCHED_DEBUG */
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+#endif /* CONFIG_SCHED_DEBUG */
+
/*
* Number of tasks to iterate in a single balance run.
* Limited because this is done with IRQs disabled.
next prev parent reply other threads:[~2011-07-07 20:36 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-07 5:30 [patch 00/17] CFS Bandwidth Control v7.1 Paul Turner
2011-07-07 5:30 ` [patch 01/17] sched: (fixlet) dont update shares twice on on_rq parent Paul Turner
2011-07-21 18:28 ` [tip:sched/core] sched: Don't " tip-bot for Paul Turner
2011-07-07 5:30 ` [patch 02/17] sched: hierarchical task accounting for SCHED_OTHER Paul Turner
2011-07-07 5:30 ` [patch 03/17] sched: introduce primitives to account for CFS bandwidth tracking Paul Turner
2011-07-07 13:48 ` Peter Zijlstra
2011-07-07 21:30 ` Paul Turner
2011-07-07 5:30 ` [patch 04/17] sched: validate CFS quota hierarchies Paul Turner
2011-07-07 5:30 ` [patch 05/17] sched: accumulate per-cfs_rq cpu usage and charge against bandwidth Paul Turner
2011-07-07 5:30 ` [patch 06/17] sched: add a timer to handle CFS bandwidth refresh Paul Turner
2011-07-07 5:30 ` [patch 07/17] sched: expire invalid runtime Paul Turner
2011-07-07 5:30 ` [patch 08/17] sched: add support for throttling group entities Paul Turner
2011-07-07 5:30 ` [patch 09/17] sched: add support for unthrottling " Paul Turner
2011-07-07 5:30 ` [patch 10/17] sched: allow for positional tg_tree walks Paul Turner
2011-07-07 5:30 ` [patch 11/17] sched: prevent interactions with throttled entities Paul Turner
2011-07-07 5:30 ` [patch 12/17] sched: prevent buddy " Paul Turner
2011-07-07 5:30 ` [patch 13/17] sched: migrate throttled tasks on HOTPLUG Paul Turner
2011-07-07 5:30 ` [patch 14/17] sched: throttle entities exceeding their allowed bandwidth Paul Turner
2011-07-07 5:30 ` [patch 15/17] sched: add exports tracking cfs bandwidth control statistics Paul Turner
2011-07-07 5:30 ` [patch 16/17] sched: return unused runtime on group dequeue Paul Turner
2011-07-07 5:30 ` [patch 17/17] sched: add documentation for bandwidth control Paul Turner
2011-07-07 11:13 ` [patch 00/17] CFS Bandwidth Control v7.1 Peter Zijlstra
2011-07-11 1:22 ` Hu Tao
2011-07-07 11:23 ` Ingo Molnar
2011-07-07 11:28 ` Peter Zijlstra
2011-07-07 14:38 ` Peter Zijlstra
2011-07-07 14:51 ` Ingo Molnar
2011-07-07 14:54 ` Peter Zijlstra
2011-07-07 14:56 ` Ingo Molnar
2011-07-07 16:23 ` Jason Baron
2011-07-07 17:20 ` Peter Zijlstra
2011-07-07 18:15 ` Jason Baron
2011-07-07 20:36 ` Peter Zijlstra [this message]
2011-07-08 9:20 ` jump_label defaults (was Re: [patch 00/17] CFS Bandwidth Control v7.1) Peter Zijlstra
2011-07-08 15:47 ` Jason Baron
2011-07-07 16:52 ` [patch 00/17] CFS Bandwidth Control v7.1 Andi Kleen
2011-07-07 17:08 ` Peter Zijlstra
2011-07-07 17:59 ` Peter Zijlstra
2011-07-07 19:36 ` Jason Baron
2011-07-08 7:45 ` Paul Turner
2011-07-08 7:39 ` Paul Turner
2011-07-08 10:32 ` Peter Zijlstra
2011-07-09 7:34 ` Paul Turner
2011-07-10 18:12 ` Ingo Molnar
2011-07-07 14:06 ` Peter Zijlstra
2011-07-08 7:35 ` Paul Turner
2011-07-11 1:22 ` Hu Tao
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