From: Rik van Riel riel@redhat.com
commit 3913cc3507575273beb165a5e027a081913ed507 upstream
With the lazy FPU code gone, we no longer use the counter field in struct fpu for anything. Get rid it.
Signed-off-by: Rik van Riel riel@redhat.com Reviewed-by: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bp@alien8.de Cc: Brian Gerst brgerst@gmail.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Denys Vlasenko dvlasenk@redhat.com Cc: Fenghua Yu fenghua.yu@intel.com Cc: H. Peter Anvin hpa@zytor.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Oleg Nesterov oleg@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Quentin Casasnovas quentin.casasnovas@oracle.com Cc: Thomas Gleixner tglx@linutronix.de Cc: pbonzini@redhat.com Link: http://lkml.kernel.org/r/1475627678-20788-6-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Daniel Sangorrin daniel.sangorrin@toshiba.co.jp ---
This is the 2nd of 3 patches that I backported to remove fpu lazy mode deadcode from stable 4.4. I had to fix one conflict manually caused by 4.4.y not having commit d1898b733619 ("x86/fpu: Add tracepoints to dump FPU state at key points")
arch/x86/include/asm/fpu/internal.h | 3 --- arch/x86/include/asm/fpu/types.h | 11 ----------- arch/x86/kernel/fpu/core.c | 3 --- 3 files changed, 17 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 7796e04..c8ba9b8 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -581,15 +581,12 @@ switch_fpu_prepare(struct fpu *old_fpu, struct fpu *new_fpu, int cpu)
/* Don't change CR0.TS if we just switch! */ if (fpu.preload) { - new_fpu->counter++; __fpregs_activate(new_fpu); prefetch(&new_fpu->state); } } else { - old_fpu->counter = 0; old_fpu->last_cpu = -1; if (fpu.preload) { - new_fpu->counter++; if (fpu_want_lazy_restore(new_fpu, cpu)) fpu.preload = 0; else diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index 1c6f6ac..dcb85a9 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -303,17 +303,6 @@ struct fpu { unsigned char fpregs_active;
/* - * @counter: - * - * This counter contains the number of consecutive context switches - * during which the FPU stays used. If this is over a threshold, the - * lazy FPU restore logic becomes eager, to save the trap overhead. - * This is an unsigned char so that after 256 iterations the counter - * wraps and the context switch behavior turns lazy again; this is to - * deal with bursty apps that only use the FPU for a short time: - */ - unsigned char counter; - /* * @state: * * In-memory copy of all FPU registers that we save/restore diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index b282364..b322325 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -250,7 +250,6 @@ static void fpu_copy(struct fpu *dst_fpu, struct fpu *src_fpu)
int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) { - dst_fpu->counter = 0; dst_fpu->fpregs_active = 0; dst_fpu->last_cpu = -1;
@@ -353,7 +352,6 @@ void fpu__restore(struct fpu *fpu) kernel_fpu_disable(); fpregs_activate(fpu); copy_kernel_to_fpregs(&fpu->state); - fpu->counter++; kernel_fpu_enable(); } EXPORT_SYMBOL_GPL(fpu__restore); @@ -370,7 +368,6 @@ EXPORT_SYMBOL_GPL(fpu__restore); void fpu__drop(struct fpu *fpu) { preempt_disable(); - fpu->counter = 0;
if (fpu->fpregs_active) { /* Ignore delayed exceptions from user space */