linux-kernel - Re: [PATCH 00/40] Memory allocation profiling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 3 May 2023 12:28:39 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Suren Baghdasaryan <surenb@...gle.com>
Cc:     Michal Hocko <mhocko@...e.com>, 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, 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 00/40] Memory allocation profiling

On Wed, 3 May 2023 08:09:28 -0700
Suren Baghdasaryan <surenb@...gle.com> wrote:

> There is another issue, which I think can be solved in a smart way but
> will either affect performance or would require more memory. With the
> tracing approach we don't know beforehand how many individual
> allocation sites exist, so we have to allocate code tags (or similar
> structures for counting) at runtime vs compile time. We can be smart
> about it and allocate in batches or even preallocate more than we need
> beforehand but, as I said, it will require some kind of compromise.

This approach is actually quite common, especially since tagging every
instance is usually overkill, as if you trace function calls in a running
kernel, you will find that only a small percentage of the kernel ever
executes. It's possible that you will be allocating a lot of tags that will
never be used. If run time allocation is possible, that is usually the
better approach.

-- Steve