Messages in this thread | | | Subject | Re: [PATCH 2/2 v2] x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok flag | From | "H. Peter Anvin" <> | Date | Sun, 10 Feb 2013 14:33:39 -0800 |
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Yes... safer that way.
Borislav Petkov <bp@alien8.de> wrote:
>On Sun, Feb 10, 2013 at 04:37:27PM -0500, Len Brown wrote: >> From: Len Brown <len.brown@intel.com> >> >> Remove 32-bit x86 a cmdline param "no-hlt", >> and the cpuinfo_x86.hlt_works_ok that it sets. >> >> If a user wants to avoid HLT, then "idle=poll" >> is much more useful, as it avoids invocation of HLT >> in idle, while "no-hlt" failed to do so. >> >> Indeed, hlt_works_ok was consulted in only 3 places. >> >> First, in /proc/cpuinfo where "hlt_bug yes" >> would be printed if and only if the user booted >> the system with "no-hlt" -- as there was no other code >> to set that flag. >> >> Second, check_hlt() would not invoke halt() if "no-hlt" >> were on the cmdline. >> >> Third, it was consulted in stop_this_cpu(), which is invoked >> by native_machine_halt()/reboot_interrupt()/smp_stop_nmi_callback() >-- >> all cases where the machine is being shutdown/reset. >> The flag was not consulted in the more frequently invoked >> play_dead()/hlt_play_dead() used in processor offline and suspend. >> >> Since Linux-3.0 there has been a run-time notice upon "no-hlt" >invocations >> indicating that it would be removed in 2012. >> >> Signed-off-by: Len Brown <len.brown@intel.com> >> Cc: x86@kernel.org >> --- >> v2: remove also check_hlt() > >[ … ] > >> diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c >> index 3286a92..e280253 100644 >> --- a/arch/x86/kernel/cpu/proc.c >> +++ b/arch/x86/kernel/cpu/proc.c >> @@ -28,7 +28,6 @@ static void show_cpuinfo_misc(struct seq_file *m, >struct cpuinfo_x86 *c) >> { >> seq_printf(m, >> "fdiv_bug\t: %s\n" >> - "hlt_bug\t\t: %s\n" > >Are we fine with changing /proc/cpuinfo output? We tend to consider it >an API to userspace, judging by past experience...
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