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, 138 insertions, 0 deletions

diff --git a/include/trace/events/cma.h b/include/trace/events/cma.h
new file mode 100644
index 000000000..37195edf2
--- /dev/null
+++ b/include/trace/events/cma.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cma
+
+#if !defined(_TRACE_CMA_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CMA_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(cma_release,
+
+	TP_PROTO(const char *name, unsigned long pfn, const struct page *page,
+		 unsigned long count),
+
+	TP_ARGS(name, pfn, page, count),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(unsigned long, pfn)
+		__field(const struct page *, page)
+		__field(unsigned long, count)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->pfn = pfn;
+		__entry->page = page;
+		__entry->count = count;
+	),
+
+	TP_printk("name=%s pfn=0x%lx page=%p count=%lu",
+		  __get_str(name),
+		  __entry->pfn,
+		  __entry->page,
+		  __entry->count)
+);
+
+TRACE_EVENT(cma_alloc_start,
+
+	TP_PROTO(const char *name, unsigned long request_count, unsigned long available_count,
+		unsigned long total_count, unsigned int align),
+
+	TP_ARGS(name, request_count, available_count, total_count, align),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(unsigned long, request_count)
+		__field(unsigned long, available_count)
+		__field(unsigned long, total_count)
+		__field(unsigned int, align)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->request_count = request_count;
+		__entry->available_count = available_count;
+		__entry->total_count = total_count;
+		__entry->align = align;
+	),
+
+	TP_printk("name=%s request_count=%lu available_count=%lu total_count=%lu align=%u",
+		  __get_str(name),
+		  __entry->request_count,
+		  __entry->available_count,
+		  __entry->total_count,
+		  __entry->align)
+);
+
+TRACE_EVENT(cma_alloc_finish,
+
+	TP_PROTO(const char *name, unsigned long pfn, const struct page *page,
+		 unsigned long count, unsigned int align, int errorno),
+
+	TP_ARGS(name, pfn, page, count, align, errorno),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(unsigned long, pfn)
+		__field(const struct page *, page)
+		__field(unsigned long, count)
+		__field(unsigned int, align)
+		__field(int, errorno)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->pfn = pfn;
+		__entry->page = page;
+		__entry->count = count;
+		__entry->align = align;
+		__entry->errorno = errorno;
+	),
+
+	TP_printk("name=%s pfn=0x%lx page=%p count=%lu align=%u errorno=%d",
+		  __get_str(name),
+		  __entry->pfn,
+		  __entry->page,
+		  __entry->count,
+		  __entry->align,
+		  __entry->errorno)
+);
+
+TRACE_EVENT(cma_alloc_busy_retry,
+
+	TP_PROTO(const char *name, unsigned long pfn, const struct page *page,
+		 unsigned long count, unsigned int align),
+
+	TP_ARGS(name, pfn, page, count, align),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(unsigned long, pfn)
+		__field(const struct page *, page)
+		__field(unsigned long, count)
+		__field(unsigned int, align)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->pfn = pfn;
+		__entry->page = page;
+		__entry->count = count;
+		__entry->align = align;
+	),
+
+	TP_printk("name=%s pfn=0x%lx page=%p count=%lu align=%u",
+		  __get_str(name),
+		  __entry->pfn,
+		  __entry->page,
+		  __entry->count,
+		  __entry->align)
+);
+
+#endif /* _TRACE_CMA_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>