Re: [PATCH v3 31/35] lib: add memory allocations report in show_mem()

Suren Baghdasaryan
2024-02-15T14:58:56Z

On Thu, Feb 15, 2024 at 1:22 AM Michal Hocko <mhocko@suse.com> wrote:
>
> On Mon 12-02-24 13:39:17, Suren Baghdasaryan wrote:
> [...]
> > @@ -423,4 +424,18 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
> > #ifdef CONFIG_MEMORY_FAILURE
> > printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
> > #endif
> > +#ifdef CONFIG_MEM_ALLOC_PROFILING
> > + {
> > + struct seq_buf s;
> > + char *buf = kmalloc(4096, GFP_ATOMIC);
> > +
> > + if (buf) {
> > + printk("Memory allocations:\n");
> > + seq_buf_init(&s, buf, 4096);
> > + alloc_tags_show_mem_report(&s);
> > + printk("%s", buf);
> > + kfree(buf);
> > + }
> > + }
> > +#endif
>
> I am pretty sure I have already objected to this. Memory allocations in
> the oom path are simply no go unless there is absolutely no other way
> around that. In this case the buffer could be preallocated.

Good point. We will change this to a smaller buffer allocated on the
stack and will print records one-by-one. Thanks!

>
> --
> Michal Hocko
> SUSE Labs