KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/include/trace/events/kyber.h b/include/trace/events/kyber.h
new file mode 100644
index 000000000..9d44781ef
--- /dev/null
+++ b/include/trace/events/kyber.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM kyber
+
+#if !defined(_TRACE_KYBER_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KYBER_H
+
+#include <linux/blkdev.h>
+#include <linux/tracepoint.h>
+
+#define DOMAIN_LEN		16
+#define LATENCY_TYPE_LEN	8
+
+TRACE_EVENT(kyber_latency,
+
+	TP_PROTO(dev_t dev, const char *domain, const char *type,
+		 unsigned int percentile, unsigned int numerator,
+		 unsigned int denominator, unsigned int samples),
+
+	TP_ARGS(dev, domain, type, percentile, numerator, denominator, samples),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev				)
+		__array(	char,	domain,	DOMAIN_LEN		)
+		__array(	char,	type,	LATENCY_TYPE_LEN	)
+		__field(	u8,	percentile			)
+		__field(	u8,	numerator			)
+		__field(	u8,	denominator			)
+		__field(	unsigned int,	samples			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= dev;
+		strscpy(__entry->domain, domain, sizeof(__entry->domain));
+		strscpy(__entry->type, type, sizeof(__entry->type));
+		__entry->percentile	= percentile;
+		__entry->numerator	= numerator;
+		__entry->denominator	= denominator;
+		__entry->samples	= samples;
+	),
+
+	TP_printk("%d,%d %s %s p%u %u/%u samples=%u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->domain,
+		  __entry->type, __entry->percentile, __entry->numerator,
+		  __entry->denominator, __entry->samples)
+);
+
+TRACE_EVENT(kyber_adjust,
+
+	TP_PROTO(dev_t dev, const char *domain, unsigned int depth),
+
+	TP_ARGS(dev, domain, depth),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__array(	char,	domain,	DOMAIN_LEN	)
+		__field(	unsigned int,	depth		)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= dev;
+		strscpy(__entry->domain, domain, sizeof(__entry->domain));
+		__entry->depth		= depth;
+	),
+
+	TP_printk("%d,%d %s %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->domain,
+		  __entry->depth)
+);
+
+TRACE_EVENT(kyber_throttled,
+
+	TP_PROTO(dev_t dev, const char *domain),
+
+	TP_ARGS(dev, domain),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__array(	char,	domain,	DOMAIN_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= dev;
+		strscpy(__entry->domain, domain, sizeof(__entry->domain));
+	),
+
+	TP_printk("%d,%d %s", MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->domain)
+);
+
+#define _TRACE_KYBER_H
+#endif /* _TRACE_KYBER_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>