* Re: [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu()
2015-04-27 15:10 ` [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu() Bobby Powers
@ 2015-04-27 15:19 ` Oleg Nesterov
2015-05-02 20:42 ` Bobby Powers
2015-05-04 8:11 ` Borislav Petkov
2015-05-06 10:14 ` [tip:x86/urgent] x86/fpu: Always " tip-bot for Bobby Powers
2 siblings, 1 reply; 12+ messages in thread
From: Oleg Nesterov @ 2015-04-27 15:19 UTC (permalink / raw)
To: Bobby Powers
Cc: linux-kernel, x86, Andi Kleen, Borislav Petkov, Ingo Molnar,
Andy Lutomirski, Dave Hansen, Fenghua Yu, Linus Torvalds,
Pekka Riikonen, Quentin Casasnovas, Rik van Riel, Suresh Siddha
Thanks!
On 04/27, Bobby Powers wrote:
>
> v2: switch used_math() -> tsk_used_math(tsk) to consistently use the
> grabbed tsk instead of current, like in the rest of flush_thread().
>
> Oleg's commit f893959b ("x86/fpu: Don't abuse drop_init_fpu() in
> flush_thread()") removed drop_init_fpu() usage from flush_thread.
> This seems to break things for me - the Go 1.4 test suite fails all
> over the place with floating point comparision errors (offending
> commit found through bisection).
>
> The functional change was that flush_thread after f893959b only calls
> restore_init_xstate when both use_eager_fpu() and !used_math() are
> true. drop_init_fpu (now fpu_reset_state) calls restore_init_xstate()
> regardless of whether current used_math() - apply the same logic here.
>
> Fixes: f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
> Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
> Acked-by: Oleg Nesterov <oleg@redhat.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Pekka Riikonen <priikone@iki.fi>
> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Suresh Siddha <sbsiddha@gmail.com>
> ---
> arch/x86/kernel/process.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 8213da6..1a6fcf8 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -156,11 +156,13 @@ void flush_thread(void)
> /* FPU state will be reallocated lazily at the first use. */
> drop_fpu(tsk);
> free_thread_xstate(tsk);
> - } else if (!used_math()) {
> - /* kthread execs. TODO: cleanup this horror. */
> - if (WARN_ON(init_fpu(tsk)))
> - force_sig(SIGKILL, tsk);
> - user_fpu_begin();
> + } else {
> + if (!tsk_used_math(tsk)) {
> + /* kthread execs. TODO: cleanup this horror. */
> + if (WARN_ON(init_fpu(tsk)))
> + force_sig(SIGKILL, tsk);
> + user_fpu_begin();
> + }
> restore_init_xstate();
> }
> }
> --
> 2.3.6
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu()
2015-04-27 15:19 ` Oleg Nesterov
@ 2015-05-02 20:42 ` Bobby Powers
2015-05-03 17:39 ` Oleg Nesterov
0 siblings, 1 reply; 12+ messages in thread
From: Bobby Powers @ 2015-05-02 20:42 UTC (permalink / raw)
To: Oleg Nesterov, Ingo Molnar
Cc: Kernel development list, x86, Andi Kleen, Borislav Petkov,
Andy Lutomirski, Dave Hansen, Fenghua Yu, Linus Torvalds,
Pekka Riikonen, Quentin Casasnovas, Rik van Riel, Suresh Siddha
Hello,
Oleg Nesterov <oleg@redhat.com> wrote:
> Thanks!
Dave gave this his:
Tested-By: Dave Hansen <dave.hansen@intel.com>
over under v1 of this patch:
https://lkml.kernel.org/g/5543C277.9070208@intel.com
Anything else anyone sees, or anyone in particular I have to poke at
to get this in? Ingo?
yours,
Bobby
On Mon, Apr 27, 2015 at 11:19 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> Thanks!
>
> On 04/27, Bobby Powers wrote:
>>
>> v2: switch used_math() -> tsk_used_math(tsk) to consistently use the
>> grabbed tsk instead of current, like in the rest of flush_thread().
>>
>> Oleg's commit f893959b ("x86/fpu: Don't abuse drop_init_fpu() in
>> flush_thread()") removed drop_init_fpu() usage from flush_thread.
>> This seems to break things for me - the Go 1.4 test suite fails all
>> over the place with floating point comparision errors (offending
>> commit found through bisection).
>>
>> The functional change was that flush_thread after f893959b only calls
>> restore_init_xstate when both use_eager_fpu() and !used_math() are
>> true. drop_init_fpu (now fpu_reset_state) calls restore_init_xstate()
>> regardless of whether current used_math() - apply the same logic here.
>>
>> Fixes: f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
>> Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
>> Acked-by: Oleg Nesterov <oleg@redhat.com>
>> Cc: Andi Kleen <ak@linux.intel.com>
>> Cc: Borislav Petkov <bp@suse.de>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> Cc: Andy Lutomirski <luto@amacapital.net>
>> Cc: Dave Hansen <dave.hansen@intel.com>
>> Cc: Fenghua Yu <fenghua.yu@intel.com>
>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>> Cc: Pekka Riikonen <priikone@iki.fi>
>> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
>> Cc: Rik van Riel <riel@redhat.com>
>> Cc: Suresh Siddha <sbsiddha@gmail.com>
>> ---
>> arch/x86/kernel/process.c | 12 +++++++-----
>> 1 file changed, 7 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
>> index 8213da6..1a6fcf8 100644
>> --- a/arch/x86/kernel/process.c
>> +++ b/arch/x86/kernel/process.c
>> @@ -156,11 +156,13 @@ void flush_thread(void)
>> /* FPU state will be reallocated lazily at the first use. */
>> drop_fpu(tsk);
>> free_thread_xstate(tsk);
>> - } else if (!used_math()) {
>> - /* kthread execs. TODO: cleanup this horror. */
>> - if (WARN_ON(init_fpu(tsk)))
>> - force_sig(SIGKILL, tsk);
>> - user_fpu_begin();
>> + } else {
>> + if (!tsk_used_math(tsk)) {
>> + /* kthread execs. TODO: cleanup this horror. */
>> + if (WARN_ON(init_fpu(tsk)))
>> + force_sig(SIGKILL, tsk);
>> + user_fpu_begin();
>> + }
>> restore_init_xstate();
>> }
>> }
>> --
>> 2.3.6
>>
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu()
2015-05-02 20:42 ` Bobby Powers
@ 2015-05-03 17:39 ` Oleg Nesterov
0 siblings, 0 replies; 12+ messages in thread
From: Oleg Nesterov @ 2015-05-03 17:39 UTC (permalink / raw)
To: Bobby Powers
Cc: Ingo Molnar, Kernel development list, x86, Andi Kleen,
Borislav Petkov, Andy Lutomirski, Dave Hansen, Fenghua Yu,
Linus Torvalds, Pekka Riikonen, Quentin Casasnovas, Rik van Riel,
Suresh Siddha
On 05/02, Bobby Powers wrote:
>
> Hello,
>
> Oleg Nesterov <oleg@redhat.com> wrote:
> > Thanks!
>
> Dave gave this his:
>
> Tested-By: Dave Hansen <dave.hansen@intel.com>
>
> over under v1 of this patch:
> https://lkml.kernel.org/g/5543C277.9070208@intel.com
>
> Anything else anyone sees, or anyone in particular I have to poke at
> to get this in? Ingo?
Yes, please, 4.1 needs this patch.
Borislav, perhaps you can help ?
>
> yours,
> Bobby
>
> On Mon, Apr 27, 2015 at 11:19 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> > Thanks!
> >
> > On 04/27, Bobby Powers wrote:
> >>
> >> v2: switch used_math() -> tsk_used_math(tsk) to consistently use the
> >> grabbed tsk instead of current, like in the rest of flush_thread().
> >>
> >> Oleg's commit f893959b ("x86/fpu: Don't abuse drop_init_fpu() in
> >> flush_thread()") removed drop_init_fpu() usage from flush_thread.
> >> This seems to break things for me - the Go 1.4 test suite fails all
> >> over the place with floating point comparision errors (offending
> >> commit found through bisection).
> >>
> >> The functional change was that flush_thread after f893959b only calls
> >> restore_init_xstate when both use_eager_fpu() and !used_math() are
> >> true. drop_init_fpu (now fpu_reset_state) calls restore_init_xstate()
> >> regardless of whether current used_math() - apply the same logic here.
> >>
> >> Fixes: f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
> >> Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
> >> Acked-by: Oleg Nesterov <oleg@redhat.com>
> >> Cc: Andi Kleen <ak@linux.intel.com>
> >> Cc: Borislav Petkov <bp@suse.de>
> >> Cc: Ingo Molnar <mingo@kernel.org>
> >> Cc: Andy Lutomirski <luto@amacapital.net>
> >> Cc: Dave Hansen <dave.hansen@intel.com>
> >> Cc: Fenghua Yu <fenghua.yu@intel.com>
> >> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> >> Cc: Pekka Riikonen <priikone@iki.fi>
> >> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
> >> Cc: Rik van Riel <riel@redhat.com>
> >> Cc: Suresh Siddha <sbsiddha@gmail.com>
> >> ---
> >> arch/x86/kernel/process.c | 12 +++++++-----
> >> 1 file changed, 7 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> >> index 8213da6..1a6fcf8 100644
> >> --- a/arch/x86/kernel/process.c
> >> +++ b/arch/x86/kernel/process.c
> >> @@ -156,11 +156,13 @@ void flush_thread(void)
> >> /* FPU state will be reallocated lazily at the first use. */
> >> drop_fpu(tsk);
> >> free_thread_xstate(tsk);
> >> - } else if (!used_math()) {
> >> - /* kthread execs. TODO: cleanup this horror. */
> >> - if (WARN_ON(init_fpu(tsk)))
> >> - force_sig(SIGKILL, tsk);
> >> - user_fpu_begin();
> >> + } else {
> >> + if (!tsk_used_math(tsk)) {
> >> + /* kthread execs. TODO: cleanup this horror. */
> >> + if (WARN_ON(init_fpu(tsk)))
> >> + force_sig(SIGKILL, tsk);
> >> + user_fpu_begin();
> >> + }
> >> restore_init_xstate();
> >> }
> >> }
> >> --
> >> 2.3.6
> >>
> >
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu()
2015-04-27 15:10 ` [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu() Bobby Powers
2015-04-27 15:19 ` Oleg Nesterov
@ 2015-05-04 8:11 ` Borislav Petkov
2015-05-06 10:14 ` [tip:x86/urgent] x86/fpu: Always " tip-bot for Bobby Powers
2 siblings, 0 replies; 12+ messages in thread
From: Borislav Petkov @ 2015-05-04 8:11 UTC (permalink / raw)
To: Bobby Powers
Cc: linux-kernel, x86, Oleg Nesterov, Andi Kleen, Ingo Molnar,
Andy Lutomirski, Dave Hansen, Fenghua Yu, Linus Torvalds,
Pekka Riikonen, Quentin Casasnovas, Rik van Riel, Suresh Siddha
On Mon, Apr 27, 2015 at 08:10:41AM -0700, Bobby Powers wrote:
> v2: switch used_math() -> tsk_used_math(tsk) to consistently use the
> grabbed tsk instead of current, like in the rest of flush_thread().
>
> Oleg's commit f893959b ("x86/fpu: Don't abuse drop_init_fpu() in
> flush_thread()") removed drop_init_fpu() usage from flush_thread.
> This seems to break things for me - the Go 1.4 test suite fails all
> over the place with floating point comparision errors (offending
> commit found through bisection).
>
> The functional change was that flush_thread after f893959b only calls
> restore_init_xstate when both use_eager_fpu() and !used_math() are
> true. drop_init_fpu (now fpu_reset_state) calls restore_init_xstate()
> regardless of whether current used_math() - apply the same logic here.
>
> Fixes: f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
> Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
> Acked-by: Oleg Nesterov <oleg@redhat.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Pekka Riikonen <priikone@iki.fi>
> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Suresh Siddha <sbsiddha@gmail.com>
> ---
> arch/x86/kernel/process.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
Applied, thanks.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
^ permalink raw reply [flat|nested] 12+ messages in thread
* [tip:x86/urgent] x86/fpu: Always restore_xinit_state() when use_eager_cpu()
2015-04-27 15:10 ` [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu() Bobby Powers
2015-04-27 15:19 ` Oleg Nesterov
2015-05-04 8:11 ` Borislav Petkov
@ 2015-05-06 10:14 ` tip-bot for Bobby Powers
2 siblings, 0 replies; 12+ messages in thread
From: tip-bot for Bobby Powers @ 2015-05-06 10:14 UTC (permalink / raw)
To: linux-tip-commits
Cc: sbsiddha, mingo, quentin.casasnovas, bp, torvalds, bp,
fenghua.yu, linux-kernel, tglx, riel, dave.hansen, priikone, hpa,
luto, bobbypowers, oleg
Commit-ID: c88d47480d300eaad80c213d50c9bf6077fc49bc
Gitweb: http://git.kernel.org/tip/c88d47480d300eaad80c213d50c9bf6077fc49bc
Author: Bobby Powers <bobbypowers@gmail.com>
AuthorDate: Mon, 27 Apr 2015 08:10:41 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 6 May 2015 11:22:03 +0200
x86/fpu: Always restore_xinit_state() when use_eager_cpu()
The following commit:
f893959b0898 ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
removed drop_init_fpu() usage from flush_thread(). This seems to break
things for me - the Go 1.4 test suite fails all over the place with
floating point comparision errors (offending commit found through
bisection).
The functional change was that flush_thread() after this commit
only calls restore_init_xstate() when both use_eager_fpu() and
!used_math() are true. drop_init_fpu() (now fpu_reset_state()) calls
restore_init_xstate() regardless of whether current used_math() - apply
the same logic here.
Switch used_math() -> tsk_used_math(tsk) to consistently use the grabbed
tsk instead of current, like in the rest of flush_thread().
Tested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
Link: http://lkml.kernel.org/r/1430147441-9820-1-git-send-email-bobbypowers@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/process.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index bfc99b3..6e338e3 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -156,11 +156,13 @@ void flush_thread(void)
/* FPU state will be reallocated lazily at the first use. */
drop_fpu(tsk);
free_thread_xstate(tsk);
- } else if (!used_math()) {
- /* kthread execs. TODO: cleanup this horror. */
- if (WARN_ON(init_fpu(tsk)))
- force_sig(SIGKILL, tsk);
- user_fpu_begin();
+ } else {
+ if (!tsk_used_math(tsk)) {
+ /* kthread execs. TODO: cleanup this horror. */
+ if (WARN_ON(init_fpu(tsk)))
+ force_sig(SIGKILL, tsk);
+ user_fpu_begin();
+ }
restore_init_xstate();
}
}
^ permalink raw reply related [flat|nested] 12+ messages in thread