[PATCH 0/3] x86, fpu: kernel_fpu_begin/end initial cleanups/fix
From: Oleg Nesterov
Date: Thu Jan 15 2015 - 14:20:29 EST
Add cc's.
On 01/11, riel@xxxxxxxxxx wrote:
>
> Currently the kernel will always load the FPU context, even
> when switching to a kernel thread, or to an idle thread. In
> the case of a task on a KVM VCPU going idle for a bit, and
> waking up again later, this creates a vastly inefficient
> chain of FPU context saves & loads:
I assume you will send v2.
Let me send initial kernel_fpu_begin/end cleanups, I believe they make
sense anyway and won't conflict with your changes.
This is actually resend, I sent more patches some time ago but they were
ignored.
Note that (I hope) we can do more changes on top of this series, in
particular:
- remove all checks from irq_fpu_usable() except in_kernel_fpu
- do not abuse FPU in kernel threads, this makes sense even if
use_eager_fpu(), and with or without the changes you proposed.
Please review.
Oleg.
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