linux-kernel - [GIT PULL] x86/debug change for v4.4

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Date:	Tue, 3 Nov 2015 12:05:13 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...en8.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Denys Vlasenko <dvlasenk@...hat.com>
Subject: [GIT PULL] x86/debug change for v4.4

Linus,

Please pull the latest x86-debug-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-debug-for-linus

   # HEAD: 0d44975d1e2791f6df2b84b182f49d815ba3c9e0 x86/kgdb: Replace bool_int_array[NR_CPUS] with bitmap

A single debugging related commit: compress the memory usage of a kgdb data 
structure.

 Thanks,

	Ingo

------------------>
Denys Vlasenko (1):
      x86/kgdb: Replace bool_int_array[NR_CPUS] with bitmap


 arch/x86/kernel/kgdb.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index d6178d9791db..44256a62702b 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -511,26 +511,31 @@ single_step_cont(struct pt_regs *regs, struct die_args *args)
 	return NOTIFY_STOP;
 }
 
-static int was_in_debug_nmi[NR_CPUS];
+static DECLARE_BITMAP(was_in_debug_nmi, NR_CPUS);
 
 static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
 {
+	int cpu;
+
 	switch (cmd) {
 	case NMI_LOCAL:
 		if (atomic_read(&kgdb_active) != -1) {
 			/* KGDB CPU roundup */
-			kgdb_nmicallback(raw_smp_processor_id(), regs);
-			was_in_debug_nmi[raw_smp_processor_id()] = 1;
+			cpu = raw_smp_processor_id();
+			kgdb_nmicallback(cpu, regs);
+			set_bit(cpu, was_in_debug_nmi);
 			touch_nmi_watchdog();
+
 			return NMI_HANDLED;
 		}
 		break;
 
 	case NMI_UNKNOWN:
-		if (was_in_debug_nmi[raw_smp_processor_id()]) {
-			was_in_debug_nmi[raw_smp_processor_id()] = 0;
+		cpu = raw_smp_processor_id();
+
+		if (__test_and_clear_bit(cpu, was_in_debug_nmi))
 			return NMI_HANDLED;
-		}
+
 		break;
 	default:
 		/* do nothing */
--
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