From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Mimi Zohar <zohar@linux.ibm.com>
Cc: Calvin Owens <calvinowens@fb.com>,
Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCH] tpm: Make timeout logic simpler and more robust
Date: Wed, 13 Mar 2019 15:23:53 +0200 [thread overview]
Message-ID: <20190313132353.GC4261@linux.intel.com> (raw)
In-Reply-To: <20190313132232.GB4261@linux.intel.com>
On Wed, Mar 13, 2019 at 03:22:32PM +0200, Jarkko Sakkinen wrote:
> On Tue, Mar 12, 2019 at 01:04:58PM -0400, Mimi Zohar wrote:
> > On Mon, 2019-03-11 at 16:54 -0700, Calvin Owens wrote:
> > > We're having lots of problems with TPM commands timing out, and we're
> > > seeing these problems across lots of different hardware (both v1/v2).
> > >
> > > I instrumented the driver to collect latency data, but I wasn't able to
> > > find any specific timeout to fix: it seems like many of them are too
> > > aggressive. So I tried replacing all the timeout logic with a single
> > > universal long timeout, and found that makes our TPMs 100% reliable.
> > >
> > > Given that this timeout logic is very complex, problematic, and appears
> > > to serve no real purpose, I propose simply deleting all of it.
> >
> > Normally before sending such a massive change like this, included in
> > the bug report or patch description, there would be some indication as
> > to which kernel introduced a regression. Has this always been a
> > problem? Is this something new? How new?
>
> Also: is the problem in timeouts, durations or both. Does make sense
> to fix something that isn't broken...
And maybe the fix is a too big hammer. We could possibly just decrease
the granularity but fully take it away.
/Jarkko
prev parent reply other threads:[~2019-03-13 13:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 23:54 [PATCH] tpm: Make timeout logic simpler and more robust Calvin Owens
2019-03-12 0:27 ` James Bottomley
2019-03-12 12:50 ` Jarkko Sakkinen
2019-03-12 14:42 ` James Bottomley
2019-03-12 15:39 ` Jarkko Sakkinen
2019-03-12 19:41 ` Calvin Owens
2019-03-12 16:59 ` Mimi Zohar
2019-03-12 17:14 ` James Bottomley
2019-03-12 18:32 ` Mimi Zohar
2019-03-12 19:37 ` Calvin Owens
2019-03-12 12:36 ` Jarkko Sakkinen
2019-03-12 16:56 ` Mimi Zohar
2019-03-12 14:55 ` Jarkko Sakkinen
2019-03-12 17:04 ` Mimi Zohar
2019-03-12 20:08 ` Calvin Owens
2019-03-12 20:56 ` Mimi Zohar
2019-03-13 13:22 ` Jarkko Sakkinen
2019-03-13 13:23 ` Jarkko Sakkinen [this message]
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