sh: move fpu_counter into ARCH specific thread_struct

Only a couple of arches (sh/x86) use fpu_counter in task_struct so it can
be moved out into ARCH specific thread_struct, reducing the size of
task_struct for other arches.

Compile tested sh defconfig + sh4-linux-gcc (4.6.3)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Paul Mundt <paul.mundt@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 25 insertions, 5 deletions

diff --git a/arch/sh/include/asm/fpu.h b/arch/sh/include/asm/fpu.h
index 06c4281aab65..09fc2bc8a790 100644
--- a/arch/sh/include/asm/fpu.h
+++ b/arch/sh/include/asm/fpu.h
@@ -46,7 +46,7 @@ static inline void __unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
                 save_fpu(tsk);
                 release_fpu(regs);
         } else
-                tsk->fpu_counter = 0;
+                tsk->thread.fpu_counter = 0;
 }
 
 static inline void unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index e699a12cdcca..18e0377f72bb 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -111,6 +111,16 @@ struct thread_struct {
 
         /* Extended processor state */
         union thread_xstate *xstate;
+
+        /*
+         * fpu_counter contains the number of consecutive context switches
+         * that the FPU is used. If this is over a threshold, the lazy fpu
+         * saving becomes unlazy to save the trap. This is an unsigned char
+         * so that after 256 times the counter wraps and the behavior turns
+         * lazy again; this to deal with bursty apps that only use FPU for
+         * a short time
+         */
+        unsigned char fpu_counter;
 };
 
 #define INIT_THREAD  {                                          \
diff --git a/arch/sh/include/asm/processor_64.h b/arch/sh/include/asm/processor_64.h
index 1cc7d3197143..eedd4f625d07 100644
--- a/arch/sh/include/asm/processor_64.h
+++ b/arch/sh/include/asm/processor_64.h
@@ -126,6 +126,16 @@ struct thread_struct {
 
         /* floating point info */
         union thread_xstate *xstate;
+
+        /*
+         * fpu_counter contains the number of consecutive context switches
+         * that the FPU is used. If this is over a threshold, the lazy fpu
+         * saving becomes unlazy to save the trap. This is an unsigned char
+         * so that after 256 times the counter wraps and the behavior turns
+         * lazy again; this to deal with bursty apps that only use FPU for
+         * a short time
+         */
+        unsigned char fpu_counter;
 };
 
 #define INIT_MMAP \
diff --git a/arch/sh/kernel/cpu/fpu.c b/arch/sh/kernel/cpu/fpu.c
index f8f7af51c128..4e332244ea75 100644
--- a/arch/sh/kernel/cpu/fpu.c
+++ b/arch/sh/kernel/cpu/fpu.c
@@ -44,7 +44,7 @@ void __fpu_state_restore(void)
         restore_fpu(tsk);
 
         task_thread_info(tsk)->status |= TS_USEDFPU;
-        tsk->fpu_counter++;
+        tsk->thread.fpu_counter++;
 }
 
 void fpu_state_restore(struct pt_regs *regs)
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index ebd3933005b4..2885fc9d9dcd 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -156,7 +156,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 #endif
                 ti->addr_limit = KERNEL_DS;
                 ti->status &= ~TS_USEDFPU;
-                p->fpu_counter = 0;
+                p->thread.fpu_counter = 0;
                 return 0;
         }
         *childregs = *current_pt_regs();
@@ -189,7 +189,7 @@ __switch_to(struct task_struct *prev, struct task_struct *next)
         unlazy_fpu(prev, task_pt_regs(prev));
 
         /* we're going to use this soon, after a few expensive things */
-        if (next->fpu_counter > 5)
+        if (next->thread.fpu_counter > 5)
                 prefetch(next_t->xstate);
 
 #ifdef CONFIG_MMU
@@ -207,7 +207,7 @@ __switch_to(struct task_struct *prev, struct task_struct *next)
          * restore of the math state immediately to avoid the trap; the
          * chances of needing FPU soon are obviously high now
          */
-        if (next->fpu_counter > 5)
+        if (next->thread.fpu_counter > 5)
                 __fpu_state_restore();
 
         return prev;