[PATCH] Fix a irqcount comment in entry.S

Signed-off-by: Andi Kleen <ak@suse.de>
git-mirror · Sep 26, 2006 · 96e5404 · 96e5404
1 parent 4f7fd4d
commit 96e5404
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
@@ -519,7 +519,12 @@ END(stub_rt_sigreturn)
 	testl $3,CS(%rdi)
 	je 1f
 	swapgs	
-1:	incl	%gs:pda_irqcount	# RED-PEN should check preempt count
+	/* irqcount is used to check if a CPU is already on an interrupt
+	   stack or not. While this is essentially redundant with preempt_count
+	   it is a little cheaper to use a separate counter in the PDA
+	   (short of moving irq_enter into assembly, which would be too
+	    much work) */
+1:	incl	%gs:pda_irqcount
 	cmoveq %gs:pda_irqstackptr,%rsp
 	push    %rbp			# backlink for old unwinder
 	/*