* [PATCH 2/3] x86: Move fpu_counter into ARCH specific thread_struct
2013-09-09 9:15 [PATCH 1/3] sh: Move fpu_counter into ARCH specific thread_struct Vineet Gupta
@ 2013-09-09 9:15 ` Vineet Gupta
2013-09-09 9:15 ` [PATCH 3/3] sched: Remove ARCH specific fpu_counter from task_struct Vineet Gupta
1 sibling, 0 replies; 3+ messages in thread
From: Vineet Gupta @ 2013-09-09 9:15 UTC (permalink / raw)
To: linux-kernel, linux-arch, linux-mm
Cc: Vineet Gupta, Thomas Gleixner, Ingo Molnar, H. Peter Anvin, x86,
Suresh Siddha, Borislav Petkov, Vincent Palatin, Len Brown,
Al Viro, Paul Gortmaker, Pekka Riikonen, Andrew Morton,
Dave Jones, Frederic Weisbecker, Paul E. McKenney
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 i386_defconfig + gcc 4.7.3
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Vincent Palatin <vpalatin@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
---
arch/x86/include/asm/fpu-internal.h | 10 +++++-----
arch/x86/include/asm/processor.h | 9 +++++++++
arch/x86/kernel/i387.c | 2 +-
arch/x86/kernel/process_32.c | 4 ++--
arch/x86/kernel/process_64.c | 2 +-
arch/x86/kernel/traps.c | 2 +-
6 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 4d0bda7..c49a613 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -365,7 +365,7 @@ static inline void drop_fpu(struct task_struct *tsk)
* Forget coprocessor state..
*/
preempt_disable();
- tsk->fpu_counter = 0;
+ tsk->thread.fpu_counter = 0;
__drop_fpu(tsk);
clear_used_math();
preempt_enable();
@@ -424,7 +424,7 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta
* or if the past 5 consecutive context-switches used math.
*/
fpu.preload = tsk_used_math(new) && (use_eager_fpu() ||
- new->fpu_counter > 5);
+ new->thread.fpu_counter > 5);
if (__thread_has_fpu(old)) {
if (!__save_init_fpu(old))
cpu = ~0;
@@ -433,16 +433,16 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta
/* Don't change CR0.TS if we just switch! */
if (fpu.preload) {
- new->fpu_counter++;
+ new->thread.fpu_counter++;
__thread_set_has_fpu(new);
prefetch(new->thread.fpu.state);
} else if (!use_eager_fpu())
stts();
} else {
- old->fpu_counter = 0;
+ old->thread.fpu_counter = 0;
old->thread.fpu.last_cpu = ~0;
if (fpu.preload) {
- new->fpu_counter++;
+ new->thread.fpu_counter++;
if (!use_eager_fpu() && fpu_lazy_restore(new, cpu))
fpu.preload = 0;
else
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 24cf5ae..e331f3a 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -488,6 +488,15 @@ struct thread_struct {
unsigned long iopl;
/* Max allowed port in the bitmap, in bytes: */
unsigned io_bitmap_max;
+ /*
+ * 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;
};
/*
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 5d576ab..e8368c6 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -100,7 +100,7 @@ void unlazy_fpu(struct task_struct *tsk)
__save_init_fpu(tsk);
__thread_fpu_end(tsk);
} else
- tsk->fpu_counter = 0;
+ tsk->thread.fpu_counter = 0;
preempt_enable();
}
EXPORT_SYMBOL(unlazy_fpu);
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index f8adefc..4de6e36 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -153,7 +153,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
childregs->orig_ax = -1;
childregs->cs = __KERNEL_CS | get_kernel_rpl();
childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
- p->fpu_counter = 0;
+ p->thread.fpu_counter = 0;
p->thread.io_bitmap_ptr = NULL;
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
return 0;
@@ -166,7 +166,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
p->thread.ip = (unsigned long) ret_from_fork;
task_user_gs(p) = get_user_gs(current_pt_regs());
- p->fpu_counter = 0;
+ p->thread.fpu_counter = 0;
p->thread.io_bitmap_ptr = NULL;
tsk = current;
err = -ENOMEM;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 05646ba..9b97949 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -163,7 +163,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
p->thread.sp = (unsigned long) childregs;
p->thread.usersp = me->thread.usersp;
set_tsk_thread_flag(p, TIF_FORK);
- p->fpu_counter = 0;
+ p->thread.fpu_counter = 0;
p->thread.io_bitmap_ptr = NULL;
savesegment(gs, p->thread.gsindex);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 1b23a1c..f350d7e 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -649,7 +649,7 @@ void math_state_restore(void)
return;
}
- tsk->fpu_counter++;
+ tsk->thread.fpu_counter++;
}
EXPORT_SYMBOL_GPL(math_state_restore);
--
1.8.1.2
--
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^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 3/3] sched: Remove ARCH specific fpu_counter from task_struct
2013-09-09 9:15 [PATCH 1/3] sh: Move fpu_counter into ARCH specific thread_struct Vineet Gupta
2013-09-09 9:15 ` [PATCH 2/3] x86: " Vineet Gupta
@ 2013-09-09 9:15 ` Vineet Gupta
1 sibling, 0 replies; 3+ messages in thread
From: Vineet Gupta @ 2013-09-09 9:15 UTC (permalink / raw)
To: linux-kernel, linux-arch, linux-mm
Cc: Vineet Gupta, Ingo Molnar, Peter Zijlstra
fpu_counter in task_struct was used only by sh/x86.
Both of these now carry it in ARCH specific thread_struct, hence this
can now be removed from generic task_struct, shrinking it slightly for
other arches.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
include/linux/sched.h | 9 ---------
1 file changed, 9 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 078066d..b560364 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1051,15 +1051,6 @@ struct task_struct {
struct hlist_head preempt_notifiers;
#endif
- /*
- * 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;
#ifdef CONFIG_BLK_DEV_IO_TRACE
unsigned int btrace_seq;
#endif
--
1.8.1.2
--
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^ permalink raw reply related [flat|nested] 3+ messages in thread