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Message-Id: <1251283864.3514.25.camel@raz>
Date: Wed, 26 Aug 2009 13:51:04 +0300
From: raz ben yehuda <raziebe@...il.com>
To: "Eric W. Biederman" <ebiederm@...ssion.com>
Cc: riel@...hat.com, mingo@...e.hu, peterz@...radead.org,
wiseman@...s.biu.ac.il, lkml <linux-kernel@...r.kernel.org>
Subject: Re: Subject:[ PATCH 001:003] OFFSCHED CORE
On Wed, 2009-08-26 at 00:29 -0700, Eric W. Biederman wrote:
> raz ben yehuda <raziebe@...il.com> writes:
>
> > OFFSCHED support.
> >
> > . A callback invoked just before halting the processor.
> > . SMP alternative work-around. we do not run smp alternatives if we are
> > left with a single processor.
> > . A set of utilities used by the offsched driver.
>
> Nacked-by: "Eric W. Biederman" <ebiederm@...ssion.com>
>
>
> Cpu hotunplug is mostly broken when it comes to irqs.
> Building on and extending broken code is just asking for trouble,
> especially for out of tree code.
I have this code for 4 years. The least of my problems was the
hot-unplugging. as for the tree, I will use git. much depends if the
patch is excepted. you say - i do.
> > process.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > smpboot.c | 13 +++++--
> > 2 files changed, 118 insertions(+), 4 deletions(-)
> >
> > Signed-off-by: raziebe@...il.com
> > ---
> > diff -X 2.6.30-offsched/Documentation/dontdiff -urN tmp/linux-2.6.30/arch/x86/kernel/process.c 2.6.30-offsched/arch/x86/kernel/process.c
> > --- tmp/linux-2.6.30/arch/x86/kernel/process.c 2009-06-10 06:05:27.000000000 +0300
> > +++ 2.6.30-offsched/arch/x86/kernel/process.c 2009-08-21 22:02:44.000000000 +0300
> > @@ -613,3 +613,112 @@
> > }
> > early_param("idle", idle_setup);
> >
> > +#ifdef CONFIG_HOTPLUG_CPU
> > +struct hotplug_cpu{
> > + long flags;
> > + void (*hotplug_cpu_dead)(void);
> > +};
> > +
> > +static long offsched_services;
> > +
> > +#define CPU_OFFSCHED 31
> > +#define CPU_OFFSCHED_KMEM 30
> > +#define SERVICE_TIMER 01
> > +#define SERVICE_NAPI 02
> > +
> > +DEFINE_PER_CPU(struct hotplug_cpu, offschedcpu);
> > +
> > +void unregister_offsched(int cpuid)
> > +{
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + cpu->hotplug_cpu_dead = NULL;
> > + clear_bit(CPU_OFFSCHED, &cpu->flags);
> > +}
> > +EXPORT_SYMBOL_GPL(unregister_offsched);
> > +
> > +int is_offsched(int cpuid)
> > +{
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + return test_bit(CPU_OFFSCHED, &cpu->flags);
> > +}
> > +EXPORT_SYMBOL_GPL(is_offsched);
> > +
> > +int is_offsched_kmem(int cpuid)
> > +{
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + return test_bit(CPU_OFFSCHED_KMEM, &cpu->flags);
> > +}
> > +EXPORT_SYMBOL_GPL(is_offsched_kmem);
> > +
> > +void set_offsched_kmem(int cpuid)
> > +{
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + set_bit(CPU_OFFSCHED_KMEM, &cpu->flags);
> > +}
> > +EXPORT_SYMBOL_GPL(set_offsched_kmem);
> > +
> > +void unset_offsched_kmem(int cpuid)
> > +{
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + clear_bit(CPU_OFFSCHED_KMEM, &cpu->flags);
> > +}
> > +EXPORT_SYMBOL_GPL(unset_offsched_kmem);
> > +
> > +int register_offsched(void (*offsched_callback)(void), int cpuid)
> > +{
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + if (is_offsched(cpuid))
> > + return -1;
> > + cpu->hotplug_cpu_dead = offsched_callback;
> > + set_bit(CPU_OFFSCHED, &cpu->flags);
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(register_offsched);
> > +
> > +void run_offsched(void)
> > +{
> > + int cpuid = raw_smp_processor_id();
> > + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
> > + cpu->hotplug_cpu_dead();
> > +}
> > +
> > +int offsched_is_napi_avail(void)
> > +{
> > + return SERVICE_NAPI & offsched_services;
> > +}
> > +
> > +int (*offsched_rule)(void *);
> > +EXPORT_SYMBOL(offsched_rule);
> > +/*
> > +* if we a have filter than apply filter.
> > +* return 0 if packet should go to kernel
> > +* return 1 if packet should go to offsched.
> > +*/
> > +int offsched_pkt(void *s)
> > +{
> > + if (offsched_rule)
> > + return offsched_rule(s);
> > + return 0;
> > +}
> > +
> > +void offsched_register_napi(void)
> > +{
> > + offsched_services |= SERVICE_NAPI;
> > +}
> > +EXPORT_SYMBOL_GPL(offsched_register_napi);
> > +
> > +void offsched_unregister_napi(void)
> > +{
> > + offsched_services &= ~SERVICE_NAPI;
> > +}
> > +EXPORT_SYMBOL_GPL(offsched_unregister_napi);
> > +
> > +/*
> > + * napi scheudule is called in offsched context.
> > +*/
> > +void offsched_napi_schedule(void *n)
> > +{
> > +
> > +}
> > +
> > +#endif
> > diff -X 2.6.30-offsched/Documentation/dontdiff -urN tmp/linux-2.6.30/arch/x86/kernel/smpboot.c 2.6.30-offsched/arch/x86/kernel/smpboot.c
> > --- tmp/linux-2.6.30/arch/x86/kernel/smpboot.c 2009-06-10 06:05:27.000000000 +0300
> > +++ 2.6.30-offsched/arch/x86/kernel/smpboot.c 2009-07-25 13:59:19.000000000 +0300
> > @@ -39,6 +39,8 @@
> > * Glauber Costa : i386 and x86_64 integration
> > */
> >
> > +#define DEBUG
> > +
> > #include <linux/init.h>
> > #include <linux/smp.h>
> > #include <linux/module.h>
> > @@ -686,8 +688,8 @@
> > };
> >
> > INIT_WORK(&c_idle.work, do_fork_idle);
> > -
> > - alternatives_smp_switch(1);
> > + if (!is_offsched(cpu))
> > + alternatives_smp_switch(1);
> >
> > c_idle.idle = get_idle_for_cpu(cpu);
> >
> > @@ -1283,8 +1285,9 @@
> > for (i = 0; i < 10; i++) {
> > /* They ack this in play_dead by setting CPU_DEAD */
> > if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
> > - printk(KERN_INFO "CPU %d is now offline\n", cpu);
> > - if (1 == num_online_cpus())
> > + printk(KERN_INFO "CPU %d is now offline %s\n", cpu,
> > + is_offsched(cpu) ? "and OFFSCHED" : "");
> > + if (1 == num_online_cpus() && !is_offsched(cpu))
> > alternatives_smp_switch(0);
> > return;
> > }
> > @@ -1313,6 +1316,8 @@
> > void native_play_dead(void)
> > {
> > play_dead_common();
> > + if (is_offsched(raw_smp_processor_id()))
> > + run_offsched();
> > wbinvd_halt();
> > }
> >
> >
> >
> > --
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