Subject: + sh-move-fpu_counter-into-arch-specific-thread_struct.patch added to -mm tree
To: Vineet.Gupta1@xxxxxxxxxxxx,mingo@xxxxxxxxxx,paul.mundt@xxxxxxxxx,vgupta@xxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 10 Oct 2013 14:40:12 -0700
The patch titled
Subject: sh: move fpu_counter into ARCH specific thread_struct
has been added to the -mm tree. Its filename is
sh-move-fpu_counter-into-arch-specific-thread_struct.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/sh-move-fpu_counter-into-arch-specific-thread_struct.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/sh-move-fpu_counter-into-arch-specific-thread_struct.patch
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From: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxx>
Cc: Paul Mundt <paul.mundt@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/sh/include/asm/fpu.h | 2 +-
arch/sh/include/asm/processor_32.h | 10 ++++++++++
arch/sh/include/asm/processor_64.h | 10 ++++++++++
arch/sh/kernel/cpu/fpu.c | 2 +-
arch/sh/kernel/process_32.c | 6 +++---
5 files changed, 25 insertions(+), 5 deletions(-)
diff -puN arch/sh/include/asm/fpu.h~sh-move-fpu_counter-into-arch-specific-thread_struct arch/sh/include/asm/fpu.h
--- a/arch/sh/include/asm/fpu.h~sh-move-fpu_counter-into-arch-specific-thread_struct
+++ a/arch/sh/include/asm/fpu.h
@@ -46,7 +46,7 @@ static inline void __unlazy_fpu(struct t
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 -puN arch/sh/include/asm/processor_32.h~sh-move-fpu_counter-into-arch-specific-thread_struct arch/sh/include/asm/processor_32.h
--- a/arch/sh/include/asm/processor_32.h~sh-move-fpu_counter-into-arch-specific-thread_struct
+++ a/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 -puN arch/sh/include/asm/processor_64.h~sh-move-fpu_counter-into-arch-specific-thread_struct arch/sh/include/asm/processor_64.h
--- a/arch/sh/include/asm/processor_64.h~sh-move-fpu_counter-into-arch-specific-thread_struct
+++ a/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 -puN arch/sh/kernel/cpu/fpu.c~sh-move-fpu_counter-into-arch-specific-thread_struct arch/sh/kernel/cpu/fpu.c
--- a/arch/sh/kernel/cpu/fpu.c~sh-move-fpu_counter-into-arch-specific-thread_struct
+++ a/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 -puN arch/sh/kernel/process_32.c~sh-move-fpu_counter-into-arch-specific-thread_struct arch/sh/kernel/process_32.c
--- a/arch/sh/kernel/process_32.c~sh-move-fpu_counter-into-arch-specific-thread_struct
+++ a/arch/sh/kernel/process_32.c
@@ -156,7 +156,7 @@ int copy_thread(unsigned long clone_flag
#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, st
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, st
* 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;
_
Patches currently in -mm which might be from Vineet.Gupta1@xxxxxxxxxxxx are
sh-move-fpu_counter-into-arch-specific-thread_struct.patch
x86-move-fpu_counter-into-arch-specific-thread_struct.patch
sched-remove-arch-specific-fpu_counter-from-task_struct.patch
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