linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Leonardo Bras <leonardo@linux.ibm.com>
To: John Hubbard <jhubbard@nvidia.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Arnd Bergmann <arnd@arndb.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Steven Price <steven.price@arm.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
	Balbir Singh <bsingharora@gmail.com>,
	Reza Arbab <arbab@linux.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Allison Randal <allison@lohutok.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Michal Suchanek <msuchanek@suse.de>
Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	kvm-ppc@vger.kernel.org
Subject: Re: [PATCH v6 02/11] mm/gup: Use functions to track lockless pgtbl walks on gup_pgd_range
Date: Mon, 17 Feb 2020 17:55:49 -0300	[thread overview]
Message-ID: <d0789485cc353a99e19c2d2ca4b5a628a33a312d.camel@linux.ibm.com> (raw)
In-Reply-To: <0c2f5a89-4890-fd84-6a6d-e470ba110399@nvidia.com>

[-- Attachment #1: Type: text/plain, Size: 1235 bytes --]

Hello John, comments inline;

On Fri, 2020-02-07 at 14:54 -0800, John Hubbard wrote:
> On 2/5/20 7:25 PM, Leonardo Bras wrote:
> > On Thu, 2020-02-06 at 00:08 -0300, Leonardo Bras wrote:
> > >                 gup_pgd_range(addr, end, gup_flags, pages, &nr);
> > > -               local_irq_enable();
> > > +               end_lockless_pgtbl_walk(IRQS_ENABLED);
> > >                 ret = nr;
> > >         }
> > >  
> > 
> > Just noticed IRQS_ENABLED is not available on other archs than ppc64.
> > I will fix this for v7.
> > 
> 
> What's the fix going to look like, approximately?

I am not sure what is the best approach yet. 

1. On irq_mask == 0, always enable irq on end_lockless_pgtbl_walk().
   Not sure how bat would that affect other archs.

2. Add another function like end_lockless_pgtbl_walk_irqen() that
always enables IRQ.

3. Add another parameter in end_lockless_pgtbl_walk(), so that caller
can choose ii IRQ must be enabled.

Also, not sure if internal_get_user_pages_fast() can possibly be called
with IRQ disabled, and then return with it enabled. Maybe just
saving/restoring should be fine.

Other suggestions are welcome.

> 
> 
> thanks,

Best regards,

Leonardo Bras

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

  reply	other threads:[~2020-02-17 20:58 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-06  3:08 [PATCH v6 00/11] Introduces new functions for tracking lockless pagetable walks Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 01/11] asm-generic/pgtable: Adds generic functions to track lockless pgtable walks Leonardo Bras
2020-02-06  5:54   ` Christophe Leroy
2020-02-07  2:19     ` Leonardo Bras
2020-02-07  5:39   ` kbuild test robot
2020-02-06  3:08 ` [PATCH v6 02/11] mm/gup: Use functions to track lockless pgtbl walks on gup_pgd_range Leonardo Bras
2020-02-06  3:25   ` Leonardo Bras
2020-02-07 22:54     ` John Hubbard
2020-02-17 20:55       ` Leonardo Bras [this message]
2020-10-15 14:46     ` Michal Suchánek
2020-10-16  3:27       ` Aneesh Kumar K.V
2020-02-07  1:19   ` kbuild test robot
2020-02-07  8:01   ` kbuild test robot
2020-02-06  3:08 ` [PATCH v6 03/11] powerpc/mm: Adds arch-specificic functions to track lockless pgtable walks Leonardo Bras
2020-02-06  5:46   ` Christophe Leroy
2020-02-07  4:38     ` Leonardo Bras
2020-02-17 20:32       ` Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 04/11] powerpc/mce_power: Use functions to track lockless pgtbl walks Leonardo Bras
2020-02-06  5:48   ` Christophe Leroy
2020-02-07  4:00     ` Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 05/11] powerpc/perf: " Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 06/11] powerpc/mm/book3s64/hash: " Leonardo Bras
2020-02-06  6:06   ` Christophe Leroy
2020-02-07  3:49     ` Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 07/11] powerpc/kvm/e500: " Leonardo Bras
2020-02-06  6:18   ` Christophe Leroy
2020-02-07  3:10     ` Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 08/11] powerpc/kvm/book3s_hv: " Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 09/11] powerpc/kvm/book3s_64: " Leonardo Bras
2020-02-06  3:08 ` [PATCH v6 10/11] powerpc/mm: Adds counting method to track lockless pagetable walks Leonardo Bras
2020-02-06  6:23   ` Christophe Leroy
2020-02-07  1:56     ` Leonardo Bras
2020-02-06  3:09 ` [PATCH v6 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing Leonardo Bras

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=d0789485cc353a99e19c2d2ca4b5a628a33a312d.camel@linux.ibm.com \
    --to=leonardo@linux.ibm.com \
    --cc=akpm@linux-foundation.org \
    --cc=allison@lohutok.net \
    --cc=aneesh.kumar@linux.ibm.com \
    --cc=arbab@linux.ibm.com \
    --cc=arnd@arndb.de \
    --cc=benh@kernel.crashing.org \
    --cc=bsingharora@gmail.com \
    --cc=christophe.leroy@c-s.fr \
    --cc=gregkh@linuxfoundation.org \
    --cc=jhubbard@nvidia.com \
    --cc=kvm-ppc@vger.kernel.org \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mahesh@linux.vnet.ibm.com \
    --cc=mpe@ellerman.id.au \
    --cc=msuchanek@suse.de \
    --cc=npiggin@gmail.com \
    --cc=paulus@samba.org \
    --cc=robin.murphy@arm.com \
    --cc=rppt@linux.ibm.com \
    --cc=steven.price@arm.com \
    --cc=tglx@linutronix.de \
    /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).