From: "Michael S. Tsirkin" <mst@redhat.com>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Gavin Shan <gshan@redhat.com>, linux-mm <linux-mm@kvack.org>,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
shan.gavin@gmail.com, Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [PATCH v3 2/4] mm/page_reporting: Export reporting order as module parameter
Date: Thu, 24 Jun 2021 15:02:33 -0400 [thread overview]
Message-ID: <20210624150033-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CAKgT0Uc134iSUp9vQPz6VSe9sV+AaueEfMGkbkjFrv5zhZ1szg@mail.gmail.com>
On Thu, Jun 24, 2021 at 06:55:13AM -0700, Alexander Duyck wrote:
> On Tue, Jun 22, 2021 at 5:34 PM Gavin Shan <gshan@redhat.com> wrote:
> >
> > The macro PAGE_REPORTING_MIN_ORDER is defined as the page reporting
> > threshold. It can't be adjusted at runtime.
> >
> > This introduces a variable (@page_reporting_order) to replace the
> > marcro (PAGE_REPORTING_MIN_ORDER). It's also exported so that the
> > page reporting order can be adjusted at runtime.
> >
> > Suggested-by: David Hildenbrand <david@redhat.com>
> > Signed-off-by: Gavin Shan <gshan@redhat.com>
> > ---
> > Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
> > mm/page_reporting.c | 8 ++++++--
> > mm/page_reporting.h | 5 ++---
> > 3 files changed, 14 insertions(+), 5 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index cb89dbdedc46..566c4b9af3cd 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -3566,6 +3566,12 @@
> > off: turn off poisoning (default)
> > on: turn on poisoning
> >
> > + page_reporting.page_reporting_order=
> > + [KNL] Minimal page reporting order
> > + Format: <integer>
> > + Adjust the minimal page reporting order. The page
> > + reporting is disabled when it exceeds (MAX_ORDER-1).
> > +
>
> Based on the issue found by Stephen I think we may need to tweak this
> a bit. I think we may want to just default this value to MAX_ORDER. We
> can override this value at registration time with the value provided
> either by the reporting device or pageblock_order if prdev->order is
> not set.
>
> > diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> > index df9c5054e1b4..293a8713ef7c 100644
> > --- a/mm/page_reporting.c
> > +++ b/mm/page_reporting.c
> > @@ -10,6 +10,10 @@
> > #include "page_reporting.h"
> > #include "internal.h"
> >
> > +unsigned int page_reporting_order = pageblock_order;
>
> Rather than setting this to pageblock_order directly you can set this
> to MAX_ORDER which should be constant. Then we can just add some
> checks in page_reporting_register to update it when pageblock_order is
> less than page_reporting_order.
>
> Then in the next patch you could tweak it so that it will use
> "prdev->order ? : pageblock_order" instead of just pageblock_order.
I like that! Much cleaner ... the patch is in -mm now, I think it's a
good idea to drop it and update to use this idea.
--
MST
next prev parent reply other threads:[~2021-06-24 19:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 2:34 [PATCH v3 0/4] mm/page_reporting: Make page reporting work on arm64 with 64KB page size Gavin Shan
2021-06-23 0:52 ` Alexander Duyck
2021-06-23 2:34 ` [PATCH v3 1/4] mm/page_reporting: Fix code style in __page_reporting_request() Gavin Shan
2021-06-23 2:34 ` [PATCH v3 2/4] mm/page_reporting: Export reporting order as module parameter Gavin Shan
2021-06-24 13:55 ` Alexander Duyck
2021-06-24 19:02 ` Michael S. Tsirkin [this message]
2021-06-25 1:54 ` Gavin Shan
2021-06-23 2:34 ` [PATCH v3 3/4] mm/page_reporting: Allow driver to specify reporting order Gavin Shan
2021-06-23 2:34 ` [PATCH v3 4/4] virtio_balloon: Specify page reporting order if needed Gavin Shan
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