[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAJuCfpHrZ4kWYFPvA3W9J+CmNMuOtGa_ZMXE9fOmKsPQeNt2tg@mail.gmail.com>
Date: Wed, 3 May 2023 08:18:39 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: Michal Hocko <mhocko@...e.com>
Cc: akpm@...ux-foundation.org, kent.overstreet@...ux.dev,
vbabka@...e.cz, hannes@...xchg.org, roman.gushchin@...ux.dev,
mgorman@...e.de, dave@...olabs.net, willy@...radead.org,
liam.howlett@...cle.com, corbet@....net, void@...ifault.com,
peterz@...radead.org, juri.lelli@...hat.com, ldufour@...ux.ibm.com,
catalin.marinas@....com, will@...nel.org, arnd@...db.de,
tglx@...utronix.de, mingo@...hat.com, dave.hansen@...ux.intel.com,
x86@...nel.org, peterx@...hat.com, david@...hat.com,
axboe@...nel.dk, mcgrof@...nel.org, masahiroy@...nel.org,
nathan@...nel.org, dennis@...nel.org, tj@...nel.org,
muchun.song@...ux.dev, rppt@...nel.org, paulmck@...nel.org,
pasha.tatashin@...een.com, yosryahmed@...gle.com,
yuzhao@...gle.com, dhowells@...hat.com, hughd@...gle.com,
andreyknvl@...il.com, keescook@...omium.org,
ndesaulniers@...gle.com, gregkh@...uxfoundation.org,
ebiggers@...gle.com, ytcoode@...il.com, vincent.guittot@...aro.org,
dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
bristot@...hat.com, vschneid@...hat.com, cl@...ux.com,
penberg@...nel.org, iamjoonsoo.kim@....com, 42.hyeyoo@...il.com,
glider@...gle.com, elver@...gle.com, dvyukov@...gle.com,
shakeelb@...gle.com, songmuchun@...edance.com, jbaron@...mai.com,
rientjes@...gle.com, minchan@...gle.com, kaleshsingh@...gle.com,
kernel-team@...roid.com, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, iommu@...ts.linux.dev,
linux-arch@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-modules@...r.kernel.org,
kasan-dev@...glegroups.com, cgroups@...r.kernel.org
Subject: Re: [PATCH 34/40] lib: code tagging context capture support
On Wed, May 3, 2023 at 12:36 AM Michal Hocko <mhocko@...e.com> wrote:
>
> On Mon 01-05-23 09:54:44, Suren Baghdasaryan wrote:
> [...]
> > +static inline void add_ctx(struct codetag_ctx *ctx,
> > + struct codetag_with_ctx *ctc)
> > +{
> > + kref_init(&ctx->refcount);
> > + spin_lock(&ctc->ctx_lock);
> > + ctx->flags = CTC_FLAG_CTX_PTR;
> > + ctx->ctc = ctc;
> > + list_add_tail(&ctx->node, &ctc->ctx_head);
> > + spin_unlock(&ctc->ctx_lock);
>
> AFAIU every single tracked allocation will get its own codetag_ctx.
> There is no aggregation per allocation site or anything else. This looks
> like a scalability and a memory overhead red flag to me.
True. The allocations here would not be limited. We could introduce a
global limit to the amount of memory that we can use to store contexts
and maybe reuse the oldest entry (in LRU fashion) when we hit that
limit?
>
> > +}
> > +
> > +static inline void rem_ctx(struct codetag_ctx *ctx,
> > + void (*free_ctx)(struct kref *refcount))
> > +{
> > + struct codetag_with_ctx *ctc = ctx->ctc;
> > +
> > + spin_lock(&ctc->ctx_lock);
>
> This could deadlock when allocator is called from the IRQ context.
I see. spin_lock_irqsave() then?
Thanks for the feedback!
Suren.
>
> > + /* ctx might have been removed while we were using it */
> > + if (!list_empty(&ctx->node))
> > + list_del_init(&ctx->node);
> > + spin_unlock(&ctc->ctx_lock);
> > + kref_put(&ctx->refcount, free_ctx);
> --
> Michal Hocko
> SUSE Labs
Powered by blists - more mailing lists