x86/fpu: Remove struct fpu::counter

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>

4 files changed, 1 insertions, 21 deletions

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 7801d32347a2..499d6ed0e376 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -581,16 +581,13 @@ 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);
                         trace_x86_fpu_regs_activated(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 48df486b02f9..e31332d6f0e8 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -322,17 +322,6 @@ 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/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h
index 9217ab1f5bf6..342e59789fcd 100644
--- a/arch/x86/include/asm/trace/fpu.h
+++ b/arch/x86/include/asm/trace/fpu.h
@@ -14,7 +14,6 @@ DECLARE_EVENT_CLASS(x86_fpu,
                 __field(struct fpu *, fpu)
                 __field(bool, fpregs_active)
                 __field(bool, fpstate_active)
-                __field(int, counter)
                 __field(u64, xfeatures)
                 __field(u64, xcomp_bv)
                 ),
@@ -23,17 +22,15 @@ DECLARE_EVENT_CLASS(x86_fpu,
                 __entry->fpu            = fpu;
                 __entry->fpregs_active  = fpu->fpregs_active;
                 __entry->fpstate_active = fpu->fpstate_active;
-                __entry->counter        = fpu->counter;
                 if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
                         __entry->xfeatures = fpu->state.xsave.header.xfeatures;
                         __entry->xcomp_bv  = fpu->state.xsave.header.xcomp_bv;
                 }
         ),
-        TP_printk("x86/fpu: %p fpregs_active: %d fpstate_active: %d counter: %d xfeatures: %llx xcomp_bv: %llx",
+        TP_printk("x86/fpu: %p fpregs_active: %d fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
                         __entry->fpu,
                         __entry->fpregs_active,
                         __entry->fpstate_active,
-                        __entry->counter,
                         __entry->xfeatures,
                         __entry->xcomp_bv
         )
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 036e14fe3b77..6a37d525bdbe 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -222,7 +222,6 @@ EXPORT_SYMBOL_GPL(fpstate_init);
 
 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;
 
@@ -430,7 +429,6 @@ void fpu__restore(struct fpu *fpu)
         trace_x86_fpu_before_restore(fpu);
         fpregs_activate(fpu);
         copy_kernel_to_fpregs(&fpu->state);
-        fpu->counter++;
         trace_x86_fpu_after_restore(fpu);
         kernel_fpu_enable();
 }
@@ -448,7 +446,6 @@ 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 */