From 6727ad9e206cc08b80d8000a4d67f8417e53539d Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Fri, 7 Oct 2016 17:02:55 -0700 Subject: nmi_backtrace: generate one-line reports for idle cpus When doing an nmi backtrace of many cores, most of which are idle, the output is a little overwhelming and very uninformative. Suppress messages for cpus that are idling when they are interrupted and just emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". We do this by grouping all the cpuidle code together into a new .cpuidle.text section, and then checking the address of the interrupted PC to see if it lies within that section. This commit suitably tags x86 and tile idle routines, and only adds in the minimal framework for other architectures. Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Tested-by: Daniel Thompson [arm] Tested-by: Petr Mladek Cc: Aaron Tomlin Cc: Peter Zijlstra (Intel) Cc: "Rafael J. Wysocki" Cc: Russell King Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/tile/kernel/entry.S | 2 +- arch/tile/kernel/vmlinux.lds.S | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/tile/kernel') diff --git a/arch/tile/kernel/entry.S b/arch/tile/kernel/entry.S index 670a3569450f..101de132e363 100644 --- a/arch/tile/kernel/entry.S +++ b/arch/tile/kernel/entry.S @@ -50,7 +50,7 @@ STD_ENTRY(smp_nap) * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and * as a result return to the function that called _cpu_idle(). */ -STD_ENTRY(_cpu_idle) +STD_ENTRY_SECTION(_cpu_idle, .cpuidle.text) movei r1, 1 IRQ_ENABLE_LOAD(r2, r3) mtspr INTERRUPT_CRITICAL_SECTION, r1 diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S index 9d449caf8910..e1baf094fba4 100644 --- a/arch/tile/kernel/vmlinux.lds.S +++ b/arch/tile/kernel/vmlinux.lds.S @@ -42,6 +42,7 @@ SECTIONS .text : AT (ADDR(.text) - LOAD_OFFSET) { HEAD_TEXT SCHED_TEXT + CPUIDLE_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT -- cgit v1.2.3