From: Mikulas Patocka <mpatocka@redhat.com>
To: Ignat Korchagin <ignat@cloudflare.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>
Cc: Mike Snitzer <snitzer@redhat.com>,
agk@redhat.com, dm-devel@redhat.com, dm-crypt@saout.de,
linux-kernel@vger.kernel.org, kernel-team@cloudflare.com
Subject: Re: [RFC PATCH 0/1] dm-crypt excessive overhead
Date: Fri, 19 Jun 2020 14:39:39 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.02.2006191429060.23991@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <20200619165548.GA24779@redhat.com>
On Fri, 19 Jun 2020, Mike Snitzer wrote:
> On Fri, Jun 19 2020 at 12:41pm -0400,
> Ignat Korchagin <ignat@cloudflare.com> wrote:
>
> > This is a follow up from the long-forgotten [1], but with some more convincing
> > evidence. Consider the following script:
> >
> > [1]: https://www.spinics.net/lists/dm-crypt/msg07516.html
> > [2]: https://blog.cloudflare.com/speeding-up-linux-disk-encryption/
> >
> > Ignat Korchagin (1):
> > Add DM_CRYPT_FORCE_INLINE flag to dm-crypt target
> >
> > drivers/md/dm-crypt.c | 55 +++++++++++++++++++++++++++++++++----------
> > 1 file changed, 43 insertions(+), 12 deletions(-)
> >
> > --
> > 2.20.1
> >
>
> Hi,
>
> I saw [2] and have been expecting something from cloudflare ever since.
> Nice to see this submission.
>
> There is useful context in your 0th patch header. I'll likely merge
> parts of this patch header with the more terse 1/1 header (reality is
> there only needed to be a single patch submission).
>
> Will review and stage accordingly if all looks fine to me. Mikulas,
> please have a look too.
>
> Thanks,
> Mike
+ if (test_bit(DM_CRYPT_FORCE_INLINE, &cc->flags)) {
+ if (in_irq()) {
+ /* Crypto API will fail hard in hard IRQ context */
+ tasklet_init(&io->tasklet, kcryptd_crypt_tasklet, (unsigned long)&io->work);
+ tasklet_schedule(&io->tasklet);
+ } else
+ kcryptd_crypt(&io->work);
+ } else {
+ INIT_WORK(&io->work, kcryptd_crypt);
+ queue_work(cc->crypt_queue, &io->work);
+ }
I'm looking at this and I'd like to know why does the crypto API fail in
hard-irq context and why does it work in tasklet context. What's the exact
reason behind this?
Mikulas
next prev parent reply other threads:[~2020-06-19 18:39 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 16:41 [RFC PATCH 0/1] dm-crypt excessive overhead Ignat Korchagin
2020-06-19 16:41 ` [RFC PATCH 1/1] Add DM_CRYPT_FORCE_INLINE flag to dm-crypt target Ignat Korchagin
2020-06-24 5:04 ` [dm-crypt] " Eric Biggers
2020-06-24 5:21 ` [dm-devel] " Damien Le Moal
2020-06-24 5:27 ` Eric Biggers
2020-06-24 6:46 ` Damien Le Moal
2020-06-24 7:24 ` Damien Le Moal
2020-06-24 7:49 ` Damien Le Moal
2020-06-24 8:24 ` Ignat Korchagin
2020-06-24 16:24 ` Eric Biggers
2020-06-24 17:00 ` Ignat Korchagin
2020-06-24 5:12 ` [dm-devel] " Damien Le Moal
2020-06-19 16:55 ` [RFC PATCH 0/1] dm-crypt excessive overhead Mike Snitzer
2020-06-19 18:39 ` Mikulas Patocka [this message]
2020-06-19 19:44 ` Ignat Korchagin
2020-06-20 1:23 ` Herbert Xu
2020-06-20 19:36 ` Mikulas Patocka
2020-06-20 21:02 ` Ignat Korchagin
2020-06-23 15:33 ` Mike Snitzer
2020-06-23 16:24 ` Ignat Korchagin
2020-06-24 0:23 ` Herbert Xu
2020-06-22 0:45 ` [dm-devel] " Damien Le Moal
2020-06-22 7:55 ` Ignat Korchagin
2020-06-22 8:08 ` Damien Le Moal
2020-06-23 15:01 ` Mike Snitzer
2020-06-23 15:07 ` Ignat Korchagin
2020-06-23 15:22 ` Mike Snitzer
2020-06-24 4:54 ` [dm-devel] " Damien Le Moal
2020-06-24 5:22 ` Mike Snitzer
2020-06-24 8:02 ` Ignat Korchagin
2020-06-24 4:28 ` Damien Le Moal
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