mm: vmalloc: add free_vmap_area_noflush trace event

This event is used in order to validate/debug a start address of freed VA,
number of currently outstanding and maximum allowed areas.

Link: https://lkml.kernel.org/r/20221018181053.434508-4-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
index afeb8003a0f25991f5647d344109270573316178..ad4e02191f356e1678a96bd5ceaab7c8cec60d4d 100644 (file)
--- a/include/trace/events/vmalloc.h
+++ b/include/trace/events/vmalloc.h
@@ -83,6 +83,40 @@ TRACE_EVENT(purge_vmap_area_lazy,
                __entry->start, __entry->end, __entry->npurged)
 );
 
+/**
+ * free_vmap_area_noflush - called when a vmap area is freed
+ * @va_start:          a start address of VA
+ * @nr_lazy:           number of current lazy pages
+ * @nr_lazy_max:       number of maximum lazy pages
+ *
+ * This event is used for a debug purpose. It gives some
+ * indication about a VA that is released, number of current
+ * outstanding areas and a maximum allowed threshold before
+ * dropping all of them.
+ */
+TRACE_EVENT(free_vmap_area_noflush,
+
+       TP_PROTO(unsigned long va_start, unsigned long nr_lazy,
+               unsigned long nr_lazy_max),
+
+       TP_ARGS(va_start, nr_lazy, nr_lazy_max),
+
+       TP_STRUCT__entry(
+               __field(unsigned long, va_start)
+               __field(unsigned long, nr_lazy)
+               __field(unsigned long, nr_lazy_max)
+       ),
+
+       TP_fast_assign(
+               __entry->va_start = va_start;
+               __entry->nr_lazy = nr_lazy;
+               __entry->nr_lazy_max = nr_lazy_max;
+       ),
+
+       TP_printk("va_start=0x%lx nr_lazy=%lu nr_lazy_max=%lu",
+               __entry->va_start, __entry->nr_lazy, __entry->nr_lazy_max)
+);
+
 #endif /*  _TRACE_VMALLOC_H */
 
 /* This part must be outside protection */