Messages in this thread |  | | Date | Sun, 9 Oct 2016 00:58:43 +0800 | From | Chen Yu <> | Subject | Re: [PATCH 2/4][RFC v2] PM / sleep: Introduce arch-specific hook for disable/enable nonboot cpus |
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Hi Andy, On Fri, Oct 07, 2016 at 12:31:41PM -0700, Andy Lutomirski wrote: > On 06/25/2016 09:18 AM, Chen Yu wrote: > >There is requirement that we need to do some arch-specific > >operations before putting the nonboot CPUs offline/online. > >One of the requirements comes from the hibernation resume > >process on x86_64, we need to kick all the offlin-CPUs > >online and offline again, in order to put them in a safe > >state, thus to avoid possible unwilling wake up during > >hibernation resume. > > > >Signed-off-by: Chen Yu <yu.c.chen@intel.com> > >--- > > kernel/cpu.c | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > >diff --git a/kernel/cpu.c b/kernel/cpu.c > >index d25266e..ce6e5e4 100644 > >--- a/kernel/cpu.c > >+++ b/kernel/cpu.c > >@@ -1017,6 +1017,16 @@ EXPORT_SYMBOL_GPL(cpu_up); > > #ifdef CONFIG_PM_SLEEP_SMP > > static cpumask_var_t frozen_cpus; > > > >+void __weak arch_disable_nonboot_cpus_pre(void) > > I don't like using __weak. It penalizes code size on architectures that > don't hook these functions. My preferred pattern is: > > include/linux/something.h: > > #include <asm/something.h> > > #ifndef arch_do_xyz > static inline void arch_do_xyz() {} > #endif > > arch/whatever/asm/something.h: > > extern void arch_do_xyz(); /* or static inline... */ > #define arch_do_xyz > > > This is totally free for architectures that don't have the hooks and it can > potentially be inlined on architectures that do have the hooks. Everyone > wins except that it's about five additional lines of code. > Thanks for your guidance, this patch was deprecated previously, but I'll take your advice the next time when writing similar patch. > --Andy Thanks, Yu
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