diff options
Diffstat (limited to 'patches/crypto__limit_more_FPU-enabled_sections.patch')
| -rw-r--r-- | patches/crypto__limit_more_FPU-enabled_sections.patch | 67 |
1 files changed, 0 insertions, 67 deletions
diff --git a/patches/crypto__limit_more_FPU-enabled_sections.patch b/patches/crypto__limit_more_FPU-enabled_sections.patch deleted file mode 100644 index c09e6227c51f..000000000000 --- a/patches/crypto__limit_more_FPU-enabled_sections.patch +++ /dev/null @@ -1,67 +0,0 @@ -Subject: crypto: limit more FPU-enabled sections -From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Date: Thu Nov 30 13:40:10 2017 +0100 - -From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> - -Those crypto drivers use SSE/AVX/… for their crypto work and in order to -do so in kernel they need to enable the "FPU" in kernel mode which -disables preemption. -There are two problems with the way they are used: -- the while loop which processes X bytes may create latency spikes and - should be avoided or limited. -- the cipher-walk-next part may allocate/free memory and may use - kmap_atomic(). - -The whole kernel_fpu_begin()/end() processing isn't probably that cheap. -It most likely makes sense to process as much of those as possible in one -go. The new *_fpu_sched_rt() schedules only if a RT task is pending. - -Probably we should measure the performance those ciphers in pure SW -mode and with this optimisations to see if it makes sense to keep them -for RT. - -This kernel_fpu_resched() makes the code more preemptible which might hurt -performance. - -Cc: stable-rt@vger.kernel.org -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Signed-off-by: Thomas Gleixner <tglx@linutronix.de> - - ---- - arch/x86/include/asm/fpu/api.h | 1 + - arch/x86/kernel/fpu/core.c | 12 ++++++++++++ - 2 files changed, 13 insertions(+) ---- ---- a/arch/x86/include/asm/fpu/api.h -+++ b/arch/x86/include/asm/fpu/api.h -@@ -28,6 +28,7 @@ extern void kernel_fpu_begin_mask(unsign - extern void kernel_fpu_end(void); - extern bool irq_fpu_usable(void); - extern void fpregs_mark_activate(void); -+extern void kernel_fpu_resched(void); - - /* Code that is unaware of kernel_fpu_begin_mask() can use this */ - static inline void kernel_fpu_begin(void) ---- a/arch/x86/kernel/fpu/core.c -+++ b/arch/x86/kernel/fpu/core.c -@@ -185,6 +185,18 @@ void kernel_fpu_end(void) - } - EXPORT_SYMBOL_GPL(kernel_fpu_end); - -+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(); -+ } -+} -+EXPORT_SYMBOL_GPL(kernel_fpu_resched); -+ - /* - * Sync the FPU register state to current's memory register state when the - * current task owns the FPU. The hardware register state is preserved. |