locking/lock_events: Don't show pvqspinlock events on bare metal (bf20616f) · Commits · 戴 / test

On bare metal, the pvqspinlock event counts will always be 0. So there is no point in showing their corresponding debugfs files. So they are skipped in this case. Signed-off-by:

Waiman Long <longman@redhat.com> Acked-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:

Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-10-longman@redhat.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/locking/lock_events.c

+27 −1

Original line number	Diff line number	Diff line
		@@ -115,6 +115,29 @@ static const struct file_operations fops_lockevent = {
		.llseek = default_llseek,
		};

		#ifdef CONFIG_PARAVIRT_SPINLOCKS
		#include <asm/paravirt.h>

		static bool __init skip_lockevent(const char *name)
		{
		static int pv_on __initdata = -1;

		if (pv_on < 0)
		pv_on = !pv_is_native_spin_unlock();
		/*
		* Skip PV qspinlock events on bare metal.
		*/
		if (!pv_on && !memcmp(name, "pv_", 3))
		return true;
		return false;
		}
		#else
		static inline bool skip_lockevent(const char *name)
		{
		return false;
		}
		#endif

		/*
		* Initialize debugfs for the locking event counts.
		*/
		@@ -133,10 +156,13 @@ static int __init init_lockevent_counts(void)
		* root is allowed to do the read/write to limit impact to system
		* performance.
		*/
		for (i = 0; i < lockevent_num; i++)
		for (i = 0; i < lockevent_num; i++) {
		if (skip_lockevent(lockevent_names[i]))
		continue;
		if (!debugfs_create_file(lockevent_names[i], 0400, d_counts,
		(void *)(long)i, &fops_lockevent))
		goto fail_undo;
		}

		if (!debugfs_create_file(lockevent_names[LOCKEVENT_reset_cnts], 0200,
		d_counts, (void *)(long)LOCKEVENT_reset_cnts,

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