From: Mimi Zohar <zohar@linux.ibm.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-integrity@vger.kernel.org,
Jerry Snitselaar <jsnitsel@redhat.com>,
Sumit Garg <sumit.garg@linaro.org>,
Stefan Berger <stefanb@linux.vnet.ibm.com>,
Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tpm: Detach page allocation from tpm_buf
Date: Wed, 02 Oct 2019 08:41:45 -0400 [thread overview]
Message-ID: <1570020105.4999.106.camel@linux.ibm.com> (raw)
In-Reply-To: <20190927130657.GA5556@linux.intel.com>
On Fri, 2019-09-27 at 16:06 +0300, Jarkko Sakkinen wrote:
> On Wed, Sep 25, 2019 at 10:03:46AM -0400, James Bottomley wrote:
> > On Wed, 2019-09-25 at 16:48 +0300, Jarkko Sakkinen wrote:
> > [...]
> > > + data_page = alloc_page(GFP_HIGHUSER);
> > > + if (!data_page)
> > > + return -ENOMEM;
> > > +
> > > + data_ptr = kmap(data_page);
> >
> > I don't think this is such a good idea. On 64 bit it's no different
> > from GFP_KERNEL and on 32 bit where we do have highmem, kmap space is
> > at a premium, so doing a highmem allocation + kmap is more wasteful of
> > resources than simply doing GFP_KERNEL. In general, you should only do
> > GFP_HIGHMEM if the page is going to be mostly used by userspace, which
> > really isn't the case here.
>
> Changing that in this commit would be wrong even if you are right.
> After this commit has been applied it is somewhat easier to make
> best choices for allocation in each call site (probably most will
> end up using stack).
Agreed, but it could be a separate patch, prior to this one. Why
duplicate the problem all over only to change it later?
Mimi
next prev parent reply other threads:[~2019-10-02 12:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 13:48 [PATCH] tpm: Detach page allocation from tpm_buf Jarkko Sakkinen
2019-09-25 14:03 ` James Bottomley
2019-09-27 13:06 ` Jarkko Sakkinen
2019-10-02 12:41 ` Mimi Zohar [this message]
2019-10-03 11:35 ` Jarkko Sakkinen
2019-10-03 12:50 ` Mimi Zohar
2019-10-03 18:26 ` Jarkko Sakkinen
2019-09-26 12:46 ` Jarkko Sakkinen
2019-09-26 13:12 ` Jarkko Sakkinen
2019-10-02 12:40 ` Mimi Zohar
2019-10-03 11:32 ` Jarkko Sakkinen
2019-10-03 11:33 ` Jarkko Sakkinen
2019-10-03 15:24 ` Mimi Zohar
2019-10-03 18:33 ` Jarkko Sakkinen
2019-10-03 12:39 ` Mimi Zohar
2019-10-03 18:31 ` Jarkko Sakkinen
2019-09-26 17:23 Jarkko Sakkinen
2019-09-27 15:42 ` Jarkko Sakkinen
2019-09-28 7:58 ` Jerry Snitselaar
2019-10-01 20:51 ` Jarkko Sakkinen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1570020105.4999.106.camel@linux.ibm.com \
--to=zohar@linux.ibm.com \
--cc=James.Bottomley@HansenPartnership.com \
--cc=arnd@arndb.de \
--cc=gregkh@linuxfoundation.org \
--cc=jarkko.sakkinen@linux.intel.com \
--cc=jgg@ziepe.ca \
--cc=jsnitsel@redhat.com \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=peterhuewe@gmx.de \
--cc=stefanb@linux.vnet.ibm.com \
--cc=sumit.garg@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).