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author | Matthew Cassell <mcassell411@gmail.com> | 2024-02-22 20:46:17 +0100 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2024-03-05 02:01:14 +0100 |
commit | f5eec03611d9352c8b19134ecd4742a6ebc45282 (patch) | |
tree | 622df520c307f66b80d24837dcb88455dee5c8f8 /mm/util.c | |
parent | sched/numa, mm: do not try to migrate memory to memoryless nodes (diff) | |
download | linux-f5eec03611d9352c8b19134ecd4742a6ebc45282.tar.xz linux-f5eec03611d9352c8b19134ecd4742a6ebc45282.zip |
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/20240222194617.1255-1-mcassell411@gmail.com
Signed-off-by: Matthew Cassell <mcassell411@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/util.c')
-rw-r--r-- | mm/util.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/util.c b/mm/util.c index 5a6a9802583b..6710efaf1802 100644 --- a/mm/util.c +++ b/mm/util.c @@ -942,6 +942,7 @@ EXPORT_SYMBOL_GPL(vm_memory_committed); int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) { long allowed; + unsigned long bytes_failed; vm_acct_memory(pages); @@ -976,8 +977,9 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; error: - pr_warn_ratelimited("%s: pid: %d, comm: %s, not enough memory for the allocation\n", - __func__, current->pid, current->comm); + bytes_failed = pages << PAGE_SHIFT; + pr_warn_ratelimited("%s: pid: %d, comm: %s, bytes: %lu not enough memory for the allocation\n", + __func__, current->pid, current->comm, bytes_failed); vm_unacct_memory(pages); return -ENOMEM; |