Re: [PATCH] lib/vdso: Use __arch_use_vsyscall() to indicate fallback

2019-10-21 Thread Thomas Gleixner
On Sun, 20 Oct 2019, Andy Lutomirski wrote: > On Sat, Oct 19, 2019 at 3:01 AM Thomas Gleixner wrote: > > __arch_use_vsyscall() is a pointless exercise TBH. The VDSO data should be > > updated unconditionally so all the trivial interfaces like time() and > > getres() just work independently of the

Re: [PATCH] lib/vdso: Use __arch_use_vsyscall() to indicate fallback

2019-10-20 Thread Andy Lutomirski
On Sat, Oct 19, 2019 at 3:01 AM Thomas Gleixner wrote: > > On Sat, 19 Oct 2019, Huacai Chen wrote: > > On Fri, Oct 18, 2019 at 11:15 AM Andy Lutomirski wrote: > > > > > > On Thu, Oct 17, 2019 at 7:57 PM Huacai Chen wrote: > > > > > > > > In do_hres(), we currently use whether the return value of

Re: [PATCH] lib/vdso: Use __arch_use_vsyscall() to indicate fallback

2019-10-19 Thread Thomas Gleixner
On Sat, 19 Oct 2019, Huacai Chen wrote: > On Fri, Oct 18, 2019 at 11:15 AM Andy Lutomirski wrote: > > > > On Thu, Oct 17, 2019 at 7:57 PM Huacai Chen wrote: > > > > > > In do_hres(), we currently use whether the return value of __arch_get_ > > > hw_counter() is negtive to indicate fallback, but t

Re: [PATCH] lib/vdso: Use __arch_use_vsyscall() to indicate fallback

2019-10-18 Thread Huacai Chen
Hi, Andy, On Fri, Oct 18, 2019 at 11:15 AM Andy Lutomirski wrote: > > On Thu, Oct 17, 2019 at 7:57 PM Huacai Chen wrote: > > > > In do_hres(), we currently use whether the return value of __arch_get_ > > hw_counter() is negtive to indicate fallback, but this is not a good > > idea. Because: > >

Re: [PATCH] lib/vdso: Use __arch_use_vsyscall() to indicate fallback

2019-10-18 Thread Vincenzo Frascino
Hi Andy and Hucan, On 10/18/19 4:15 AM, Andy Lutomirski wrote: > On Thu, Oct 17, 2019 at 7:57 PM Huacai Chen wrote: >> >> In do_hres(), we currently use whether the return value of __arch_get_ >> hw_counter() is negtive to indicate fallback, but this is not a good >> idea. Because: >> >> 1, ARM64

Re: [PATCH] lib/vdso: Use __arch_use_vsyscall() to indicate fallback

2019-10-17 Thread Andy Lutomirski
On Thu, Oct 17, 2019 at 7:57 PM Huacai Chen wrote: > > In do_hres(), we currently use whether the return value of __arch_get_ > hw_counter() is negtive to indicate fallback, but this is not a good > idea. Because: > > 1, ARM64 returns ULL_MAX but MIPS returns 0 when clock_mode is invalid; > 2, For