From: Dan Williams <dan.j.williams@intel.com>
To: David Hildenbrand <david@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>,
Logan Gunthorpe <logang@deltatee.com>,
Linux MM <linux-mm@kvack.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 06/12] mm/hotplug: Add mem-hotplug restrictions for remove_memory()
Date: Wed, 24 Apr 2019 11:07:52 -0700 [thread overview]
Message-ID: <CAPcyv4imzm5reh7d-p4Xyt=Sdoi5WDFC6t9FgLaZVexbWfGG5Q@mail.gmail.com> (raw)
In-Reply-To: <3dda9d08-a572-65b9-2f2f-da978a008deb@redhat.com>
On Tue, Apr 23, 2019 at 2:21 PM David Hildenbrand <david@redhat.com> wrote:
>
> On 17.04.19 20:39, Dan Williams wrote:
> > Teach the arch_remove_memory() path to consult the same 'struct
> > mhp_restrictions' context as was specified at arch_add_memory() time.
> >
> > No functional change, this is a preparation step for teaching
> > __remove_pages() about how and when to allow sub-section hot-remove, and
> > a cleanup for an unnecessary "is_dev_zone()" special case.
>
> I am not yet sure if this is the right thing to do. When adding memory,
> we obviously have to specify the "how". When removing memory, we usually
> should be able to look such stuff up.
True, the implementation can just use find_memory_block(), and no need
to plumb this flag.
>
>
> > void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
> > - unsigned long nr_pages, struct vmem_altmap *altmap)
> > + unsigned long nr_pages, struct mhp_restrictions *restrictions)
> > {
> > unsigned long i;
> > - unsigned long map_offset = 0;
> > int sections_to_remove;
> > + unsigned long map_offset = 0;
> > + struct vmem_altmap *altmap = restrictions->altmap;
> >
> > - /* In the ZONE_DEVICE case device driver owns the memory region */
> > - if (is_dev_zone(zone)) {
> > - if (altmap)
> > - map_offset = vmem_altmap_offset(altmap);
> > - }
> > + if (altmap)
> > + map_offset = vmem_altmap_offset(altmap);
> >
>
> Why weren't we able to use this exact same hunk before? (after my
> resource deletion cleanup of course)
>
> IOW, do we really need struct mhp_restrictions here?
We don't need it. It was only the memblock info why I added the
"restrictions" argument.
> After I factor out memory device handling into the caller of
> arch_remove_memory(), also the next patch ("mm/sparsemem: Prepare for
> sub-section ranges") should no longer need it. Or am I missing something?
That patch is still needed for the places where it adds the @nr_pages
argument, but the mhp_restrictions related bits can be dropped. The
subsection_check() helper needs to be refactored a bit to not rely on
mhp_restrictions.
next prev parent reply other threads:[~2019-04-24 18:08 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 18:38 [PATCH v6 00/12] mm: Sub-section memory hotplug support Dan Williams
2019-04-17 18:39 ` [PATCH v6 01/12] mm/sparsemem: Introduce struct mem_section_usage Dan Williams
2019-05-01 23:25 ` Pavel Tatashin
2019-05-02 6:07 ` Dan Williams
2019-05-02 14:16 ` Pavel Tatashin
2019-05-04 0:22 ` Dan Williams
2019-05-04 15:55 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 02/12] mm/sparsemem: Introduce common definitions for the size and mask of a section Dan Williams
2019-05-02 14:53 ` Pavel Tatashin
2019-05-03 0:41 ` Dan Williams
2019-05-03 10:35 ` Robin Murphy
2019-05-03 12:57 ` Pavel Tatashin
2019-05-03 13:00 ` Oscar Salvador
2019-04-17 18:39 ` [PATCH v6 03/12] mm/sparsemem: Add helpers track active portions of a section at boot Dan Williams
2019-04-25 14:33 ` Oscar Salvador
2019-04-25 14:43 ` Oscar Salvador
2019-04-26 12:57 ` Oscar Salvador
2019-05-02 16:12 ` Pavel Tatashin
2019-05-04 19:26 ` Dan Williams
2019-04-17 18:39 ` [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal Dan Williams
2019-04-19 23:09 ` Ralph Campbell
2019-04-19 23:13 ` Dan Williams
2019-04-26 13:59 ` Oscar Salvador
2019-04-26 14:00 ` Oscar Salvador
2019-05-02 19:18 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 05/12] mm/sparsemem: Convert kmalloc_section_memmap() to populate_section_memmap() Dan Williams
2019-05-02 19:28 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 06/12] mm/hotplug: Add mem-hotplug restrictions for remove_memory() Dan Williams
2019-04-23 21:21 ` David Hildenbrand
2019-04-24 18:07 ` Dan Williams [this message]
2019-04-17 18:39 ` [PATCH v6 07/12] mm: Kill is_dev_zone() helper Dan Williams
2019-04-17 20:17 ` David Hildenbrand
2019-04-26 14:04 ` Oscar Salvador
2019-05-02 20:37 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 08/12] mm/sparsemem: Prepare for sub-section ranges Dan Williams
2019-05-02 21:25 ` Pavel Tatashin
2019-04-17 18:39 ` [PATCH v6 09/12] mm/sparsemem: Support sub-section hotplug Dan Williams
2019-04-17 18:39 ` [PATCH v6 10/12] mm/devm_memremap_pages: Enable sub-section remap Dan Williams
2019-04-17 18:39 ` [PATCH v6 11/12] libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields Dan Williams
2019-04-17 22:02 ` Andrew Morton
2019-04-17 22:09 ` Dan Williams
2019-04-17 18:39 ` [PATCH v6 12/12] libnvdimm/pfn: Stop padding pmem namespaces to section alignment Dan Williams
2019-04-17 22:03 ` [PATCH v6 00/12] mm: Sub-section memory hotplug support Andrew Morton
2019-04-17 22:59 ` Dan Williams
2019-04-18 2:09 ` Dan Williams
2019-04-18 12:45 ` Jeff Moyer
2019-04-19 3:25 ` Dan Williams
2019-04-23 13:16 ` Oscar Salvador
2019-04-24 20:43 ` Pavel Tatashin
2019-05-02 22:46 ` Pavel Tatashin
2019-05-02 23:20 ` Dan Williams
2019-05-02 23:21 ` Dan Williams
2019-05-03 10:48 ` Oscar Salvador
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