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From: Suren Baghdasaryan <surenb@google.com>
Date: Thu, 21 Mar 2024 14:08:34 -0700
Message-ID: <CAJuCfpG-KiE-MyOR0ZCghOswDMKS-9SmBh_UEdzSf4GHTB1wBg@mail.gmail.com>
Subject: Re: [PATCH v6 00/37] Memory allocation profiling
To: Andrew Morton <akpm@linux-foundation.org>
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On Thu, Mar 21, 2024 at 1:42=E2=80=AFPM Andrew Morton <akpm@linux-foundatio=
n.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] fu=
nc: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!