From: Yi Zhang <yi.z.zhang@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Pasha Tatashin" <pavel.tatashin@microsoft.com>,
"Michal Hocko" <mhocko@suse.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Ingo Molnar" <mingo@kernel.org>, "Linux MM" <linux-mm@kvack.org>,
"Dave Hansen" <dave.hansen@intel.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
rppt@linux.vnet.ibm.com, alexander.h.duyck@linux.intel.com,
"Andrew Morton" <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap
Date: Wed, 10 Oct 2018 20:52:12 +0800 [thread overview]
Message-ID: <20181010125211.GA45572@tiger-server> (raw)
In-Reply-To: <CAPcyv4gZV_V=iY0mHiiAWwbynqtPxLTwdZ0j0vQ0F95ZZ4nTZg@mail.gmail.com>
On 2018-10-09 at 14:19:32 -0700, Dan Williams wrote:
> On Tue, Oct 9, 2018 at 1:34 PM Alexander Duyck
> <alexander.h.duyck@linux.intel.com> wrote:
> >
> > On 10/9/2018 11:04 AM, Dan Williams wrote:
> > > On Tue, Oct 9, 2018 at 3:21 AM Yi Zhang <yi.z.zhang@linux.intel.com> wrote:
> [..]
> > > That comment is incorrect, device-pages are never onlined. So I think
> > > we can just skip that call to __SetPageReserved() unless the memory
> > > range is MEMORY_DEVICE_{PRIVATE,PUBLIC}.
> > >
> >
> > When pages are "onlined" via __free_pages_boot_core they clear the
> > reserved bit, that is the reason for the comment. The reserved bit is
> > meant to indicate that the page cannot be swapped out or moved based on
> > the description of the bit.
>
> ...but ZONE_DEVICE pages are never onlined so I would expect
> memmap_init_zone_device() to know that detail.
>
> > I would think with that being the case we still probably need the call
> > to __SetPageReserved to set the bit with the expectation that it will
> > not be cleared for device-pages since the pages are not onlined.
> > Removing the call to __SetPageReserved would probably introduce a number
> > of regressions as there are multiple spots that use the reserved bit to
> > determine if a page can be swapped out to disk, mapped as system memory,
> > or migrated.
Another things, it seems page_init/set_reserved already been done in the
move_pfn_range_to_zone
|-->memmap_init_zone
|-->for_each_page_in_pfn
|-->__init_single_page
|-->SetPageReserved
Why we haven't remove these redundant initial in memmap_init_zone?
Correct me if I missed something.
>
> Right, this is what Yi is working on... the PageReserved flag is
> problematic for KVM. Auditing those locations it seems as long as we
> teach hibernation to avoid ZONE_DEVICE ranges we can safely not set
> the reserved flag for DAX pages. What I'm trying to avoid is a local
> KVM hack to check for DAX pages when the Reserved flag is not
> otherwise needed.
Thanks Dan. Provide the patch link.
https://lore.kernel.org/lkml/cover.1536342881.git.yi.z.zhang@linux.intel.com
> _______________________________________________
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> Linux-nvdimm@lists.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm
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next prev parent reply other threads:[~2018-10-10 6:12 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 20:18 [PATCH v5 0/4] Address issues slowing persistent memory initialization Alexander Duyck
2018-09-25 20:19 ` [PATCH v5 1/4] mm: Remove now defunct NO_BOOTMEM from depends list for deferred init Alexander Duyck
2018-09-25 21:05 ` Mike Rapoport
2018-09-25 20:20 ` [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling page init poisoning Alexander Duyck
2018-09-25 20:26 ` Dave Hansen
2018-09-25 20:38 ` Alexander Duyck
2018-09-25 22:14 ` Dave Hansen
2018-09-25 22:27 ` Alexander Duyck
2018-09-26 7:38 ` Michal Hocko
2018-09-26 15:24 ` Alexander Duyck
2018-09-26 15:39 ` Michal Hocko
2018-09-26 15:41 ` Dave Hansen
2018-09-26 16:18 ` Alexander Duyck
2018-09-26 15:36 ` Dave Hansen
2018-09-26 22:36 ` Andrew Morton
2018-09-25 20:20 ` [PATCH v5 3/4] mm: Create non-atomic version of SetPageReserved for init use Alexander Duyck
2018-09-25 20:21 ` [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Alexander Duyck
2018-09-26 7:55 ` Michal Hocko
2018-09-26 18:25 ` Alexander Duyck
2018-09-26 18:52 ` Dan Williams
2018-09-27 11:20 ` Michal Hocko
2018-09-27 11:09 ` Michal Hocko
2018-09-27 12:25 ` Oscar Salvador
2018-09-27 13:13 ` Michal Hocko
2018-09-27 14:50 ` Oscar Salvador
2018-09-27 15:41 ` David Hildenbrand
2018-09-28 8:12 ` Oscar Salvador
2018-09-28 8:44 ` Oscar Salvador
2018-09-28 15:50 ` Dan Williams
2018-09-27 12:32 ` Oscar Salvador
2018-10-08 21:01 ` Dan Williams
2018-10-08 21:38 ` Alexander Duyck
2018-10-08 22:00 ` Dan Williams
2018-10-08 22:07 ` Alexander Duyck
2018-10-08 22:36 ` Alexander Duyck
2018-10-08 22:59 ` Dan Williams
2018-10-08 23:34 ` [mm PATCH] memremap: Fix reference count for pgmap in devm_memremap_pages Alexander Duyck
2018-10-09 0:20 ` Dan Williams
2018-10-09 17:00 ` [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Yi Zhang
2018-10-09 18:04 ` Dan Williams
2018-10-09 20:26 ` Alexander Duyck
2018-10-09 21:19 ` Dan Williams
2018-10-10 12:52 ` Yi Zhang [this message]
2018-10-10 15:27 ` Alexander Duyck
2018-10-11 8:17 ` Yi Zhang
2018-10-10 9:58 ` Michal Hocko
2018-10-10 16:39 ` Alexander Duyck
2018-10-10 17:24 ` Michal Hocko
2018-10-10 17:39 ` Alexander Duyck
2018-10-10 17:53 ` Michal Hocko
2018-10-10 18:13 ` Alexander Duyck
2018-10-10 18:52 ` Michal Hocko
2018-10-11 8:55 ` Michal Hocko
2018-10-11 17:38 ` Alexander Duyck
2018-10-11 18:22 ` Dan Williams
2018-10-17 7:52 ` Michal Hocko
2018-10-17 15:02 ` Alexander Duyck
2018-10-29 14:12 ` Michal Hocko
2018-10-29 15:59 ` Alexander Duyck
2018-10-29 16:35 ` Michal Hocko
2018-10-29 17:01 ` Alexander Duyck
2018-10-29 17:24 ` Michal Hocko
2018-10-29 17:34 ` Dan Williams
2018-10-29 17:45 ` Michal Hocko
2018-10-29 17:42 ` Alexander Duyck
2018-10-29 18:18 ` Michal Hocko
2018-10-29 19:59 ` Alexander Duyck
2018-10-30 6:29 ` Michal Hocko
2018-10-30 6:55 ` Dan Williams
2018-10-30 8:17 ` Michal Hocko
2018-10-30 15:57 ` Dan Williams
2018-10-30 8:05 ` Oscar Salvador
2018-10-29 15:49 ` Dan Williams
2018-10-29 15:56 ` Michal Hocko
2018-10-10 18:18 ` Dan Williams
2018-10-11 8:39 ` Yi Zhang
2018-10-11 15:38 ` Alexander Duyck
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