mm: vmalloc: add alloc_vmap_area trace event

Patch series "Add basic trace events for vmap/vmalloc (v2)", v2.

This small series add some basic trace events for the vmap/vmalloc code.
Since currently we lack any, sometimes it is hard to start debuging vmap
code if an issue is reported or occured.

For example https://lore.kernel.org/linux-mm/Y0p8BZIiDXLQbde%2F@pc636/T/

The final patch adds two reviewers for vmalloc code.

This patch (of 7):

It is for debug purposes and for validation of passed parameters.

Link: https://lkml.kernel.org/r/20221018181053.434508-1-urezki@gmail.com
Link: https://lkml.kernel.org/r/20221018181053.434508-2-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/trace/events/vmalloc.h b/include/trace/events/vmalloc.h
new file mode 100644 (file)
index 0000000..39fbd77
--- /dev/null
+++ b/include/trace/events/vmalloc.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM vmalloc
+
+#if !defined(_TRACE_VMALLOC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_VMALLOC_H
+
+#include <linux/tracepoint.h>
+
+/**
+ * alloc_vmap_area - called when a new vmap allocation occurs
+ * @addr:      an allocated address
+ * @size:      a requested size
+ * @align:     a requested alignment
+ * @vstart:    a requested start range
+ * @vend:      a requested end range
+ * @failed:    an allocation failed or not
+ *
+ * This event is used for a debug purpose, it can give an extra
+ * information for a developer about how often it occurs and which
+ * parameters are passed for further validation.
+ */
+TRACE_EVENT(alloc_vmap_area,
+
+       TP_PROTO(unsigned long addr, unsigned long size, unsigned long align,
+               unsigned long vstart, unsigned long vend, int failed),
+
+       TP_ARGS(addr, size, align, vstart, vend, failed),
+
+       TP_STRUCT__entry(
+               __field(unsigned long, addr)
+               __field(unsigned long, size)
+               __field(unsigned long, align)
+               __field(unsigned long, vstart)
+               __field(unsigned long, vend)
+               __field(int, failed)
+       ),
+
+       TP_fast_assign(
+               __entry->addr = addr;
+               __entry->size = size;
+               __entry->align = align;
+               __entry->vstart = vstart;
+               __entry->vend = vend;
+               __entry->failed = failed;
+       ),
+
+       TP_printk("va_start: %lu size=%lu align=%lu vstart=0x%lx vend=0x%lx failed=%d",
+               __entry->addr, __entry->size, __entry->align,
+               __entry->vstart, __entry->vend, __entry->failed)
+);
+
+#endif /*  _TRACE_VMALLOC_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>