Re: [PATCH v6 00/37] Memory allocation profiling

Suren Baghdasaryan
2024-03-21T21:08:48Z

On Thu, Mar 21, 2024 at 1:42 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Thu, 21 Mar 2024 09:36:22 -0700 Suren Baghdasaryan <surenb@google.com> wrote:
>
> > Low overhead [1] per-callsite memory allocation profiling. Not just for
> > debug kernels, overhead low enough to be deployed in production.
> >
> > Example output:
> > root@moria-kvm:~# sort -rn /proc/allocinfo
> > 127664128 31168 mm/page_ext.c:270 func:alloc_page_ext
> > 56373248 4737 mm/slub.c:2259 func:alloc_slab_page
> > 14880768 3633 mm/readahead.c:247 func:page_cache_ra_unbounded
> > 14417920 3520 mm/mm_init.c:2530 func:alloc_large_system_hash
> > 13377536 234 block/blk-mq.c:3421 func:blk_mq_alloc_rqs
> > 11718656 2861 mm/filemap.c:1919 func:__filemap_get_folio
> > 9192960 2800 kernel/fork.c:307 func:alloc_thread_stack_node
> > 4206592 4 net/netfilter/nf_conntrack_core.c:2567 func:nf_ct_alloc_hashtable
> > 4136960 1010 drivers/staging/ctagmod/ctagmod.c:20 [ctagmod] func:ctagmod_start
> > 3940352 962 mm/memory.c:4214 func:alloc_anon_folio
> > 2894464 22613 fs/kernfs/dir.c:615 func:__kernfs_new_node
>
> Did you consider adding a knob to permit all the data to be wiped out?
> So people can zap everything, run the chosen workload then go see what
> happened?
>
> Of course, this can be done in userspace by taking a snapshot before
> and after, then crunching on the two....

Yeah, that's exactly what I was envisioning. Don't think we need to
complicate more by adding a reset functionality unless there are other
reasons for it. Thanks!