From: Daniel Sangorrin <daniel.sangorrin@toshiba.co.jp>
To: stable@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>, Borislav Petkov <bp@alien8.de>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Fenghua Yu <fenghua.yu@intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Quentin Casasnovas <quentin.casasnovas@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
pbonzini@redhat.com, Ingo Molnar <mingo@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bo Gan <ganb@vmware.com>, Alexey Makhalov <amakhalov@vmware.com>,
"Matt Helsley (VMware)" <matt.helsley@gmail.com>,
Borislav Petkov <bp@suse.de>, Andy Lutomirski <luto@kernel.org>,
yu-cheng yu <yu-cheng.yu@intel.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v4 4.4 3/4] x86/fpu: Remove struct fpu::counter
Date: Tue, 16 Oct 2018 16:00:02 +0900 [thread overview]
Message-ID: <1539673203-21068-4-git-send-email-daniel.sangorrin@toshiba.co.jp> (raw)
In-Reply-To: <1539673203-21068-1-git-send-email-daniel.sangorrin@toshiba.co.jp>
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>
---
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 2ff03cc..16825dd 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -575,15 +575,12 @@ 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 */
--
2.7.4
next prev parent reply other threads:[~2018-10-16 7:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1539673203-21068-1-git-send-email-daniel.sangorrin@toshiba.co.jp>
2018-10-16 7:00 ` [PATCH v4 4.4 1/4] KVM: x86: remove eager_fpu field of struct kvm_vcpu_arch Daniel Sangorrin
2018-10-16 7:00 ` [PATCH v4 4.4 2/4] x86/fpu: Remove use_eager_fpu() Daniel Sangorrin
2018-10-16 7:00 ` Daniel Sangorrin [this message]
2018-10-16 7:00 ` [PATCH v4 4.4 4/4] x86/fpu: Finish excising 'eagerfpu' Daniel Sangorrin
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