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, 301 insertions, 0 deletions

diff --git a/include/trace/events/ceph.h b/include/trace/events/ceph.h
new file mode 100644
index 000000000..1b990632f
--- /dev/null
+++ b/include/trace/events/ceph.h
@@ -0,0 +1,301 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Ceph filesystem support module tracepoints
+ *
+ * Copyright (C) 2025 IONOS SE. All Rights Reserved.
+ * Written by Max Kellermann (max.kellermann@ionos.com)
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ceph
+
+#if !defined(_TRACE_CEPH_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CEPH_H
+
+#include <linux/tracepoint.h>
+
+#define ceph_mdsc_suspend_reasons						\
+	EM(ceph_mdsc_suspend_reason_no_mdsmap,		"no-mdsmap")		\
+	EM(ceph_mdsc_suspend_reason_no_active_mds,	"no-active-mds")	\
+	EM(ceph_mdsc_suspend_reason_rejected,		"rejected")		\
+	E_(ceph_mdsc_suspend_reason_session,		"session")
+
+#ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
+#define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
+
+#undef EM
+#undef E_
+#define EM(a, b) a,
+#define E_(a, b) a
+
+enum ceph_mdsc_suspend_reason { ceph_mdsc_suspend_reasons } __mode(byte);
+
+#endif
+
+/*
+ * Export enum symbols via userspace.
+ */
+#undef EM
+#undef E_
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define E_(a, b) TRACE_DEFINE_ENUM(a);
+
+ceph_mdsc_suspend_reasons;
+
+/*
+ * Now redefine the EM() and E_() macros to map the enums to the strings that
+ * will be printed in the output.
+ */
+#undef EM
+#undef E_
+#define EM(a, b)	{ a, b },
+#define E_(a, b)	{ a, b }
+
+TRACE_EVENT(ceph_mdsc_submit_request,
+	TP_PROTO(struct ceph_mds_client *mdsc,
+		 struct ceph_mds_request *req),
+
+	TP_ARGS(mdsc, req),
+
+	TP_STRUCT__entry(
+		__field(u64,	tid)
+		__field(int,	op)
+		__field(u64,	ino)
+		__field(u64,	snap)
+	),
+
+	TP_fast_assign(
+		struct inode *inode;
+
+		__entry->tid = req->r_tid;
+		__entry->op = req->r_op;
+
+		inode = req->r_inode;
+		if (inode == NULL && req->r_dentry)
+			inode = d_inode(req->r_dentry);
+
+		if (inode) {
+			__entry->ino = ceph_ino(inode);
+			__entry->snap = ceph_snap(inode);
+		} else {
+			__entry->ino = __entry->snap = 0;
+		}
+	),
+
+	TP_printk("R=%llu op=%s ino=%llx,%llx",
+		  __entry->tid,
+		  ceph_mds_op_name(__entry->op),
+		  __entry->ino, __entry->snap)
+);
+
+TRACE_EVENT(ceph_mdsc_suspend_request,
+	TP_PROTO(struct ceph_mds_client *mdsc,
+		     struct ceph_mds_session *session,
+		     struct ceph_mds_request *req,
+		     enum ceph_mdsc_suspend_reason reason),
+
+	TP_ARGS(mdsc, session, req, reason),
+
+	TP_STRUCT__entry(
+		__field(u64,				tid)
+		__field(int,				op)
+		__field(int,				mds)
+		__field(enum ceph_mdsc_suspend_reason,	reason)
+	),
+
+	TP_fast_assign(
+		__entry->tid = req->r_tid;
+		__entry->op = req->r_op;
+		__entry->mds = session ? session->s_mds : -1;
+		__entry->reason = reason;
+	),
+
+	TP_printk("R=%llu op=%s reason=%s",
+		  __entry->tid,
+		  ceph_mds_op_name(__entry->op),
+		  __print_symbolic(__entry->reason, ceph_mdsc_suspend_reasons))
+);
+
+TRACE_EVENT(ceph_mdsc_resume_request,
+	TP_PROTO(struct ceph_mds_client *mdsc,
+		 struct ceph_mds_request *req),
+
+	TP_ARGS(mdsc, req),
+
+	TP_STRUCT__entry(
+		__field(u64,				tid)
+		__field(int,				op)
+	),
+
+	TP_fast_assign(
+		__entry->tid = req->r_tid;
+		__entry->op = req->r_op;
+	),
+
+	TP_printk("R=%llu op=%s",
+		  __entry->tid,
+		  ceph_mds_op_name(__entry->op))
+);
+
+TRACE_EVENT(ceph_mdsc_send_request,
+	TP_PROTO(struct ceph_mds_session *session,
+		 struct ceph_mds_request *req),
+
+	TP_ARGS(session, req),
+
+	TP_STRUCT__entry(
+		__field(u64,		tid)
+		__field(int,		op)
+		__field(int,		mds)
+	),
+
+	TP_fast_assign(
+		__entry->tid = req->r_tid;
+		__entry->op = req->r_op;
+		__entry->mds = session->s_mds;
+	),
+
+	TP_printk("R=%llu op=%s mds=%d",
+		  __entry->tid,
+		  ceph_mds_op_name(__entry->op),
+		  __entry->mds)
+);
+
+TRACE_EVENT(ceph_mdsc_complete_request,
+	TP_PROTO(struct ceph_mds_client *mdsc,
+		     struct ceph_mds_request *req),
+
+	TP_ARGS(mdsc, req),
+
+	TP_STRUCT__entry(
+		__field(u64,			tid)
+		__field(int,			op)
+		__field(int,			err)
+		__field(unsigned long,		latency_ns)
+	),
+
+	TP_fast_assign(
+		__entry->tid = req->r_tid;
+		__entry->op = req->r_op;
+		__entry->err = req->r_err;
+		__entry->latency_ns = req->r_end_latency - req->r_start_latency;
+	),
+
+	TP_printk("R=%llu op=%s err=%d latency_ns=%lu",
+		  __entry->tid,
+		  ceph_mds_op_name(__entry->op),
+		  __entry->err,
+		  __entry->latency_ns)
+);
+
+TRACE_EVENT(ceph_handle_caps,
+	TP_PROTO(struct ceph_mds_client *mdsc,
+		 struct ceph_mds_session *session,
+		 int op,
+		 const struct ceph_vino *vino,
+		 struct ceph_inode_info *inode,
+		 u32 seq, u32 mseq, u32 issue_seq),
+
+	TP_ARGS(mdsc, session, op, vino, inode, seq, mseq, issue_seq),
+
+	TP_STRUCT__entry(
+		__field(int,	mds)
+		__field(int,	op)
+		__field(u64,	ino)
+		__field(u64,	snap)
+		__field(u32,	seq)
+		__field(u32,	mseq)
+		__field(u32,	issue_seq)
+	),
+
+	TP_fast_assign(
+		__entry->mds = session->s_mds;
+		__entry->op = op;
+		__entry->ino = vino->ino;
+		__entry->snap = vino->snap;
+		__entry->seq = seq;
+		__entry->mseq = mseq;
+		__entry->issue_seq = issue_seq;
+	),
+
+	TP_printk("mds=%d op=%s vino=%llx.%llx seq=%u iseq=%u mseq=%u",
+		  __entry->mds,
+		  ceph_cap_op_name(__entry->op),
+		  __entry->ino,
+		  __entry->snap,
+		  __entry->seq,
+		  __entry->issue_seq,
+		  __entry->mseq)
+);
+
+/*
+ * Client reset tracepoints - identify the client by its monitor-
+ * assigned global_id so traces remain meaningful when kernel pointer
+ * hashing is enabled.
+ */
+TRACE_EVENT(ceph_client_reset_schedule,
+	TP_PROTO(const struct ceph_mds_client *mdsc, const char *reason),
+	TP_ARGS(mdsc, reason),
+	TP_STRUCT__entry(
+		__field(u64, client_id)
+		__string(reason, reason ? reason : "")
+	),
+	TP_fast_assign(
+		__entry->client_id = mdsc->fsc->client->monc.auth ?
+			mdsc->fsc->client->monc.auth->global_id : 0;
+		__assign_str(reason);
+	),
+	TP_printk("client_id=%llu reason=%s",
+		  __entry->client_id, __get_str(reason))
+);
+
+TRACE_EVENT(ceph_client_reset_complete,
+	TP_PROTO(const struct ceph_mds_client *mdsc, int ret),
+	TP_ARGS(mdsc, ret),
+	TP_STRUCT__entry(
+		__field(u64, client_id)
+		__field(int, ret)
+	),
+	TP_fast_assign(
+		__entry->client_id = mdsc->fsc->client->monc.auth ?
+			mdsc->fsc->client->monc.auth->global_id : 0;
+		__entry->ret = ret;
+	),
+	TP_printk("client_id=%llu ret=%d", __entry->client_id, __entry->ret)
+);
+
+TRACE_EVENT(ceph_client_reset_blocked,
+	TP_PROTO(const struct ceph_mds_client *mdsc, int blocked_count),
+	TP_ARGS(mdsc, blocked_count),
+	TP_STRUCT__entry(
+		__field(u64, client_id)
+		__field(int, blocked_count)
+	),
+	TP_fast_assign(
+		__entry->client_id = mdsc->fsc->client->monc.auth ?
+			mdsc->fsc->client->monc.auth->global_id : 0;
+		__entry->blocked_count = blocked_count;
+	),
+	TP_printk("client_id=%llu blocked_count=%d", __entry->client_id,
+		  __entry->blocked_count)
+);
+
+TRACE_EVENT(ceph_client_reset_unblocked,
+	TP_PROTO(const struct ceph_mds_client *mdsc, int ret),
+	TP_ARGS(mdsc, ret),
+	TP_STRUCT__entry(
+		__field(u64, client_id)
+		__field(int, ret)
+	),
+	TP_fast_assign(
+		__entry->client_id = mdsc->fsc->client->monc.auth ?
+			mdsc->fsc->client->monc.auth->global_id : 0;
+		__entry->ret = ret;
+	),
+	TP_printk("client_id=%llu ret=%d", __entry->client_id, __entry->ret)
+);
+
+#undef EM
+#undef E_
+#endif /* _TRACE_CEPH_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>