mm/util.c: add byte count to __vm_enough_memory failure warning

Commit 44b414c8715c5dcf53288 ("mm/util.c: add warning if
__vm_enough_memory fails") adds debug information which gives the process
id and executable name should __vm_enough_memory() fail.  Adding the
number of pages to the failure message would benefit application
developers and system administrators in debugging overambitious memory
requests by providing a point of reference to the amount of memory causing
__vm_enough_memory() to fail.

1. Set appropriate kernel tunable to reach code path for failure
   message:

	# echo 2 > /proc/sys/vm/overcommit_memory

2. Test program to generate failure - requests 1 gibibyte per
   iteration:

	#include <stdlib.h>
	#include <stdio.h>

	int main(int argc, char **argv) {
		for(;;) {
			if(malloc(1<<30) == NULL)
				break;

			printf("allocated 1 GiB\n");
		}

		return 0;
	}

3. Output:

	Before:

	__vm_enough_memory: pid: 1218, comm: a.out, not enough memory
for the allocation

	After:

	__vm_enough_memory: pid: 1137, comm: a.out, bytes: 1073741824,
not enough memory for the allocation

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Cassell <[email protected]>
Cc: David Hildenbrand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions