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authorMatthew Cassell <mcassell411@gmail.com>2024-02-22 20:46:17 +0100
committerAndrew Morton <akpm@linux-foundation.org>2024-03-05 02:01:14 +0100
commitf5eec03611d9352c8b19134ecd4742a6ebc45282 (patch)
tree622df520c307f66b80d24837dcb88455dee5c8f8 /mm/util.c
parentsched/numa, mm: do not try to migrate memory to memoryless nodes (diff)
downloadlinux-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.c6
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;