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From:   Mauricio Faria de Oliveira <mfo@canonical.com>
Date:   Fri, 12 Jun 2020 15:32:43 -0300
Message-ID: <CAO9xwp1mXmS7VVau2xWcnRic1kGQO03ptjdoevAgzoCXWwuJ6A@mail.gmail.com>
Subject: Re: [v2 PATCH] crypto: af_alg - fix use-after-free in af_alg_accept()
 due to bh_lock_sock()
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     "David S. Miller" <davem@davemloft.net>,
        linux-crypto@vger.kernel.org
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Hi Herbert,

On Wed, Jun 10, 2020 at 11:28 AM Mauricio Faria de Oliveira
<mfo@canonical.com> wrote:
>
> On Tue, Jun 9, 2020 at 9:21 PM Herbert Xu <herbert@gondor.apana.org.au> wrote:
> >
> > On Tue, Jun 09, 2020 at 12:17:32PM -0300, Mauricio Faria de Oliveira wrote:
> > >
> > > Per your knowledge/experience with the crypto subsystem, the changed code
> > > paths are not hot enough to suffer from such implications?
> >
> > I don't think replacing a spin-lock with a pair of atomic ops is
> > going to be too much of an issue.  We can always look at this again
> > if someone comes up with real numbers of course.
>
> Right; I meant the other places as well, where atomic ops were added
> (in addition to the existing spinlocks.)
>
> But indeed, real numbers would be great and tell whether or not
> there's performance differences.
>
> We're working on that -- Brian (bug reporter) has access to detailed
> metrics/stats from the workload, and kindly agreed to set up two
> identical instances to compare the numbers.  I'll keep you posted.
>

Just wanted to let you know that the performance is really close for
the two patches,
both on the CPU utilization profile and also on workload results
(#requests over time).

And the tests ran for two days, so it  looks stable.

Thanks!

> Thank you,
> Mauricio
>
>
>
> >
> > Cheers,
> > --
> > Email: Herbert Xu <herbert@gondor.apana.org.au>
> > Home Page: http://gondor.apana.org.au/~herbert/
> > PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
>
>
>
> --
> Mauricio Faria de Oliveira


-- 
Mauricio Faria de Oliveira