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, 77 insertions, 0 deletions

diff --git a/include/trace/events/napi.h b/include/trace/events/napi.h
new file mode 100644
index 000000000..b567b9ffe
--- /dev/null
+++ b/include/trace/events/napi.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM napi
+
+#if !defined(_TRACE_NAPI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_NAPI_H
+
+#include <linux/netdevice.h>
+#include <linux/tracepoint.h>
+#include <linux/ftrace.h>
+
+#define NO_DEV "(no_device)"
+
+TRACE_EVENT(napi_poll,
+
+	TP_PROTO(struct napi_struct *napi, int work, int budget),
+
+	TP_ARGS(napi, work, budget),
+
+	TP_STRUCT__entry(
+		__field(	struct napi_struct *,	napi)
+		__string(	dev_name, napi->dev ? napi->dev->name : NO_DEV)
+		__field(	int,			work)
+		__field(	int,			budget)
+	),
+
+	TP_fast_assign(
+		__entry->napi = napi;
+		__assign_str(dev_name);
+		__entry->work = work;
+		__entry->budget = budget;
+	),
+
+	TP_printk("napi poll on napi struct %p for device %s work %d budget %d",
+		  __entry->napi, __get_str(dev_name),
+		  __entry->work, __entry->budget)
+);
+
+TRACE_EVENT(dql_stall_detected,
+
+	TP_PROTO(unsigned short thrs, unsigned int len,
+		 unsigned long last_reap, unsigned long hist_head,
+		 unsigned long now, unsigned long *hist),
+
+	TP_ARGS(thrs, len, last_reap, hist_head, now, hist),
+
+	TP_STRUCT__entry(
+		__field(	unsigned short,		thrs)
+		__field(	unsigned int,		len)
+		__field(	unsigned long,		last_reap)
+		__field(	unsigned long,		hist_head)
+		__field(	unsigned long,		now)
+		__array(	unsigned long,		hist, 4)
+	),
+
+	TP_fast_assign(
+		__entry->thrs = thrs;
+		__entry->len = len;
+		__entry->last_reap = last_reap;
+		__entry->hist_head = hist_head * BITS_PER_LONG;
+		__entry->now = now;
+		memcpy(__entry->hist, hist, sizeof(entry->hist));
+	),
+
+	TP_printk("thrs %u  len %u  last_reap %lu  hist_head %lu  now %lu  hist %016lx %016lx %016lx %016lx",
+		  __entry->thrs, __entry->len,
+		  __entry->last_reap, __entry->hist_head, __entry->now,
+		  __entry->hist[0], __entry->hist[1],
+		  __entry->hist[2], __entry->hist[3])
+);
+
+#undef NO_DEV
+
+#endif /* _TRACE_NAPI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>