Messages in this thread | | | Date | Fri, 13 Mar 2015 11:52:51 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 4/4] x86/fpu: don't abuse drop_init_fpu() in flush_thread() |
| |
On Wed, Mar 11, 2015 at 06:35:07PM +0100, Oleg Nesterov wrote: > drop_init_fpu() makes no sense. We need drop_fpu() and only if
Oh, please explain why. I can try to rhyme it up as something like "we don't need to restore FPU context when flushing the thread" but I'm not sure...
> !use_eager_fpu(). > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > arch/x86/kernel/process.c | 11 ++++------- > 1 files changed, 4 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c > index c396de2..2e71120 100644 > --- a/arch/x86/kernel/process.c > +++ b/arch/x86/kernel/process.c > @@ -131,14 +131,11 @@ void flush_thread(void) > flush_ptrace_hw_breakpoint(tsk); > memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); > > - drop_init_fpu(tsk); > - /* > - * Free the FPU state for non xsave platforms. They get reallocated > - * lazily at the first use. > - */ > - if (!use_eager_fpu()) > + if (!use_eager_fpu()) { > + /* FPU state will be reallocated lazily at the first use. */ > + drop_fpu(tsk); > free_thread_xstate(tsk); > - else if (!used_math()) { > + } else if (!used_math()) { > /* kthread execs. TODO: cleanup this horror. */ > if (WARN_ON(init_fpu(current))) > force_sig(SIGKILL, current);
Also, can we clean up the tsk/current usage here?
We assign current to tsk and we work with it but then later use current again. Needlessly confusing.
Thanks.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
| |