Commit 8147bc15 authored Sep 03, 2025 by Yueyang Pan Committed by Andrew Morton Sep 21, 2025

mm/show_mem: add trylock while printing alloc info

In production, show_mem() can be called concurrently from two different
entities, for example one from oom_kill_process() another from
__alloc_pages_slowpath from another kthread.  This patch adds a spinlock
and invokes trylock before printing out the kernel alloc info in
show_mem().  This way two alloc info won't interleave with each other,
which then makes parsing easier.

Link: https://lkml.kernel.org/r/4ed91296e0c595d945a38458f7a8d9611b0c1e52.1756897825.git.pyyjason@gmail.com


Signed-off-by: Yueyang Pan <pyyjason@gmail.com>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 9abd8bd4

mm/show_mem.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -425,7 +425,9 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
		printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
		#endif
		#ifdef CONFIG_MEM_ALLOC_PROFILING
		{
		static DEFINE_SPINLOCK(mem_alloc_profiling_spinlock);

		if (spin_trylock(&mem_alloc_profiling_spinlock)) {
		struct codetag_bytes tags[10];
		size_t i, nr;

		@@ -452,6 +454,7 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
		ct->lineno, ct->function);
		}
		}
		spin_unlock(&mem_alloc_profiling_spinlock);
		}
		#endif
		}