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, 207 insertions, 0 deletions

diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h
new file mode 100644
index 000000000..8851727ae
--- /dev/null
+++ b/include/trace/events/damon.h
@@ -0,0 +1,207 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM damon
+
+#if !defined(_TRACE_DAMON_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DAMON_H
+
+#include <linux/damon.h>
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(damos_stat_after_apply_interval,
+
+	TP_PROTO(unsigned int context_idx, unsigned int scheme_idx,
+		struct damos_stat *stat),
+
+	TP_ARGS(context_idx, scheme_idx, stat),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, context_idx)
+		__field(unsigned int, scheme_idx)
+		__field(unsigned long, nr_tried)
+		__field(unsigned long, sz_tried)
+		__field(unsigned long, nr_applied)
+		__field(unsigned long, sz_applied)
+		__field(unsigned long, sz_ops_filter_passed)
+		__field(unsigned long, qt_exceeds)
+		__field(unsigned long, nr_snapshots)
+	),
+
+	TP_fast_assign(
+		__entry->context_idx = context_idx;
+		__entry->scheme_idx = scheme_idx;
+		__entry->nr_tried = stat->nr_tried;
+		__entry->sz_tried = stat->sz_tried;
+		__entry->nr_applied = stat->nr_applied;
+		__entry->sz_applied = stat->sz_applied;
+		__entry->sz_ops_filter_passed = stat->sz_ops_filter_passed;
+		__entry->qt_exceeds = stat->qt_exceeds;
+		__entry->nr_snapshots = stat->nr_snapshots;
+	),
+
+	TP_printk("ctx_idx=%u scheme_idx=%u nr_tried=%lu sz_tried=%lu "
+			"nr_applied=%lu sz_applied=%lu sz_ops_filter_passed=%lu "
+			"qt_exceeds=%lu nr_snapshots=%lu",
+			__entry->context_idx, __entry->scheme_idx,
+			__entry->nr_tried, __entry->sz_tried,
+			__entry->nr_applied, __entry->sz_applied,
+			__entry->sz_ops_filter_passed, __entry->qt_exceeds,
+			__entry->nr_snapshots)
+);
+
+TRACE_EVENT(damos_esz,
+
+	TP_PROTO(unsigned int context_idx, unsigned int scheme_idx,
+		unsigned long esz),
+
+	TP_ARGS(context_idx, scheme_idx, esz),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, context_idx)
+		__field(unsigned int, scheme_idx)
+		__field(unsigned long, esz)
+	),
+
+	TP_fast_assign(
+		__entry->context_idx = context_idx;
+		__entry->scheme_idx = scheme_idx;
+		__entry->esz = esz;
+	),
+
+	TP_printk("ctx_idx=%u scheme_idx=%u esz=%lu",
+			__entry->context_idx, __entry->scheme_idx,
+			__entry->esz)
+);
+
+TRACE_EVENT_CONDITION(damos_before_apply,
+
+	TP_PROTO(unsigned int context_idx, unsigned int scheme_idx,
+		unsigned int target_idx, struct damon_region *r,
+		unsigned int nr_accesses, unsigned int nr_regions,
+		bool do_trace),
+
+	TP_ARGS(context_idx, scheme_idx, target_idx, r, nr_accesses,
+		nr_regions, do_trace),
+
+	TP_CONDITION(do_trace),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, context_idx)
+		__field(unsigned int, scheme_idx)
+		__field(unsigned long, target_idx)
+		__field(unsigned long, start)
+		__field(unsigned long, end)
+		__field(unsigned int, nr_accesses)
+		__field(unsigned int, age)
+		__field(unsigned int, nr_regions)
+	),
+
+	TP_fast_assign(
+		__entry->context_idx = context_idx;
+		__entry->scheme_idx = scheme_idx;
+		__entry->target_idx = target_idx;
+		__entry->start = r->ar.start;
+		__entry->end = r->ar.end;
+		__entry->nr_accesses = nr_accesses;
+		__entry->age = r->age;
+		__entry->nr_regions = nr_regions;
+	),
+
+	TP_printk("ctx_idx=%u scheme_idx=%u target_idx=%lu nr_regions=%u %lu-%lu: %u %u",
+			__entry->context_idx, __entry->scheme_idx,
+			__entry->target_idx, __entry->nr_regions,
+			__entry->start, __entry->end,
+			__entry->nr_accesses, __entry->age)
+);
+
+TRACE_EVENT(damon_monitor_intervals_tune,
+
+	TP_PROTO(unsigned long sample_us),
+
+	TP_ARGS(sample_us),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, sample_us)
+	),
+
+	TP_fast_assign(
+		__entry->sample_us = sample_us;
+	),
+
+	TP_printk("sample_us=%lu", __entry->sample_us)
+);
+
+TRACE_EVENT_CONDITION(damon_region_aggregated,
+
+	TP_PROTO(unsigned int target_id, struct damon_region *r,
+		unsigned int nr_regions, unsigned int nr_probes),
+
+	TP_ARGS(target_id, r, nr_regions, nr_probes),
+
+	TP_CONDITION(nr_probes > 0),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, target_id)
+		__field(unsigned long, start)
+		__field(unsigned long, end)
+		__field(unsigned int, nr_regions)
+		__field(unsigned int, nr_accesses)
+		__field(unsigned int, age)
+		__dynamic_array(unsigned char, probe_hits, nr_probes)
+	),
+
+	TP_fast_assign(
+		__entry->target_id = target_id;
+		__entry->start = r->ar.start;
+		__entry->end = r->ar.end;
+		__entry->nr_regions = nr_regions;
+		__entry->nr_accesses = r->nr_accesses;
+		__entry->age = r->age;
+		memcpy(__get_dynamic_array(probe_hits), r->probe_hits,
+			sizeof(*r->probe_hits) * nr_probes);
+	),
+
+	TP_printk("target_id=%lu nr_regions=%u %lu-%lu: %u %u probe_hits=%s",
+			__entry->target_id, __entry->nr_regions,
+			__entry->start, __entry->end,
+			__entry->nr_accesses, __entry->age,
+			__print_hex(__get_dynamic_array(probe_hits),
+				__get_dynamic_array_len(probe_hits)))
+);
+
+TRACE_EVENT(damon_aggregated,
+
+	TP_PROTO(unsigned int target_id, struct damon_region *r,
+		unsigned int nr_regions),
+
+	TP_ARGS(target_id, r, nr_regions),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, target_id)
+		__field(unsigned int, nr_regions)
+		__field(unsigned long, start)
+		__field(unsigned long, end)
+		__field(unsigned int, nr_accesses)
+		__field(unsigned int, age)
+	),
+
+	TP_fast_assign(
+		__entry->target_id = target_id;
+		__entry->nr_regions = nr_regions;
+		__entry->start = r->ar.start;
+		__entry->end = r->ar.end;
+		__entry->nr_accesses = r->nr_accesses;
+		__entry->age = r->age;
+	),
+
+	TP_printk("target_id=%lu nr_regions=%u %lu-%lu: %u %u",
+			__entry->target_id, __entry->nr_regions,
+			__entry->start, __entry->end,
+			__entry->nr_accesses, __entry->age)
+);
+
+#endif /* _TRACE_DAMON_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>