Re: [PATCH RT v2] crypto: limit more FPU-enabled sections
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2017-12-01 13:33:03
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On 2017-12-01 12:32:35 [+0100], Peter Zijlstra wrote:
On Fri, Dec 01, 2017 at 11:44:22AM +0100, Sebastian Andrzej Siewior wrote:
…
quoted hunk ↗ jump to hunk
quoted
+static void camellia_fpu_sched_rt(struct crypt_priv *ctx) +{ + bool fpu_enabled = ctx->fpu_enabled; + + if (!fpu_enabled || !tif_need_resched_now()) + return; + camellia_fpu_end(fpu_enabled); + kernel_fpu_end(); + /* schedule due to preemptible */ + kernel_fpu_begin(); +}There's a ton of duplication in there; you're not nearly lazy enough. Why can't we do something simple like kernel_fpu_resched() ?diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index f92a6593de1e..05321b98a55a 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c@@ -130,6 +130,18 @@ void kernel_fpu_begin(void) } EXPORT_SYMBOL_GPL(kernel_fpu_begin); +void kernel_fpu_resched(void) +{ + WARN_ON_FPU(!this_cpu_read(in_kernel_fpu)); + + if (should_resched(PREEMPT_OFFSET)) { + kernel_fpu_end(); + cond_resched(); + kernel_fpu_begin();
I can do that but I would still keep it RT only to avoid the kernel_fpu_begin/end to be invoked more often on !RT. But why that cond_resched()? kernel_fpu_end() ends with preempt_enable() and this one should do the trick.
+ }
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_resched);
+
void kernel_fpu_end(void)
{
__kernel_fpu_end();Sebastian