From: riel@redhat.com
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, tglx@linutronix.de, pbonzini@redhat.com,
        mingo@redhat.com, luto@kernel.org, hpa@zytor.com,
        dave.hansen@linux.intel.com, bp@suse.de
Subject: [PATCH RFC 0/5] x86,fpu: make FPU context switching much lazier
Date: Sat,  1 Oct 2016 16:31:30 -0400
Message-Id: <1475353895-22175-1-git-send-email-riel@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 787
Lines: 16

This series is an attempt at making the x86 FPU context switching
code much lazier.  By only reloading the FPU context when a task
switches to user mode, we can avoid switching FPU context for tasks
that spin in kernel mode, and avoid reloading the FPU context for
tasks that get interrupted by a kernel thread or briefly go idle.

It also allows us to skip restoring the userspace FPU context when
exiting a KVM guest.

This series is still BROKEN.  The first 3 patches seem to work
fine in my tests (but should not, due to missing signal path
code), while the 4th test makes it easier to trigger bugs.

I am posting this to ask about obvious issues people may see,
ideas on what direction I should take this series in, and to
avoid code conflicts with Andy's plans wrt. lazy fpu mode.