mm: vmalloc: add alloc_vmap_area trace event

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>