From: Joao Martins <joao.m.martins@oracle.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Linux MM <linux-mm@kvack.org>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
Matthew Wilcox <willy@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
John Hubbard <jhubbard@nvidia.com>,
Jane Chu <jane.chu@oracle.com>,
Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
Linux NVDIMM <nvdimm@lists.linux.dev>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>
Subject: Re: [PATCH v3 08/14] mm/sparse-vmemmap: populate compound pagemaps
Date: Wed, 28 Jul 2021 19:54:00 +0100 [thread overview]
Message-ID: <d7f1e0b9-bf57-b30e-84d5-cd0e5cdadaaf@oracle.com> (raw)
In-Reply-To: <CAPcyv4jR9atodmLqk4O+RdbM9DJDvoQvAZqH03UAgAKB71Fcdg@mail.gmail.com>
On 7/28/21 7:03 PM, Dan Williams wrote:
> On Wed, Jul 28, 2021 at 8:36 AM Joao Martins <joao.m.martins@oracle.com> wrote:
> [..]
>> +/*
>> + * For compound pages bigger than section size (e.g. x86 1G compound
>> + * pages with 2M subsection size) fill the rest of sections as tail
>> + * pages.
>> + *
>> + * Note that memremap_pages() resets @nr_range value and will increment
>> + * it after each range successful onlining. Thus the value or @nr_range
>> + * at section memmap populate corresponds to the in-progress range
>> + * being onlined here.
>> + */
>> +static bool compound_section_index(unsigned long start_pfn,
>
> Oh, I was thinking this would return the actual Nth index number for
> the section within the compound page.
> A bool is ok too, but then the
> function name would be something like:
>
> reuse_compound_section()
>
> ...right?
>
Yes.
>
> [..]
>> [...] And here's compound_section_tail_huge_page() (for the last patch in the series):
>>
>>
>> @@ -690,6 +727,33 @@ static struct page * __meminit compound_section_tail_page(unsigned
>> long addr)
>> return pte_page(*ptep);
>> }
>>
>> +static struct page * __meminit compound_section_tail_huge_page(unsigned long addr,
>> + unsigned long offset, struct dev_pagemap *pgmap)
>> +{
>> + unsigned long geometry_size = pgmap_geometry(pgmap) << PAGE_SHIFT;
>> + pmd_t *pmdp;
>> +
>> + addr -= PAGE_SIZE;
>> +
>> + /*
>> + * Assuming sections are populated sequentially, the previous section's
>> + * page data can be reused.
>> + */
>> + pmdp = pmd_off_k(addr);
>> + if (!pmdp)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + /*
>> + * Reuse the tail pages vmemmap pmd page
>> + * See layout diagram in Documentation/vm/vmemmap_dedup.rst
>> + */
>> + if (offset % geometry_size > PFN_PHYS(PAGES_PER_SECTION))
>> + return pmd_page(*pmdp);
>> +
Maybe I can drop the geometry_size and just do here:
if (PHYS_PFN(offset) % pgmap_geometry(pgmap) > PAGES_PER_SECTION)
and thus drop the geometry_size variable.
>> + /* No reusable PMD fallback to PTE tail page*/
>> + return NULL;
>> +}
>> +
>> static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn,
>> unsigned long start,
>> unsigned long end, int node,
>> @@ -697,14 +761,22 @@ static int __meminit vmemmap_populate_compound_pages(unsigned long
>> start_pfn,
>> {
>> unsigned long offset, size, addr;
>>
>> - if (compound_section_index(start_pfn, pgmap)) {
>> - struct page *page;
>> + if (compound_section_index(start_pfn, pgmap, &offset)) {
>> + struct page *page, *hpage;
>> +
>> + hpage = compound_section_tail_huge_page(addr, offset);
>> + if (IS_ERR(hpage))
>> + return -ENOMEM;
>> + else if (hpage)
>
> No need for "else" after return... other than that these helpers and
> this arrangement looks good to me.
>
OK.
next prev parent reply other threads:[~2021-07-28 18:54 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 19:35 [PATCH v3 00/14] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins
2021-07-14 19:35 ` [PATCH v3 01/14] memory-failure: fetch compound_head after pgmap_pfn_valid() Joao Martins
2021-07-15 0:17 ` Dan Williams
2021-07-15 2:51 ` [External] " Muchun Song
2021-07-15 6:40 ` Christoph Hellwig
2021-07-15 9:19 ` Muchun Song
2021-07-15 13:17 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 02/14] mm/page_alloc: split prep_compound_page into head and tail subparts Joao Martins
2021-07-15 0:19 ` Dan Williams
2021-07-15 2:53 ` [External] " Muchun Song
2021-07-15 13:17 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 03/14] mm/page_alloc: refactor memmap_init_zone_device() page init Joao Martins
2021-07-15 0:20 ` Dan Williams
2021-07-14 19:35 ` [PATCH v3 04/14] mm/memremap: add ZONE_DEVICE support for compound pages Joao Martins
2021-07-15 1:08 ` Dan Williams
2021-07-15 12:52 ` Joao Martins
2021-07-15 13:06 ` Joao Martins
2021-07-15 19:48 ` Dan Williams
2021-07-30 16:13 ` Joao Martins
2021-07-22 0:38 ` Jane Chu
2021-07-22 10:56 ` Joao Martins
2021-07-15 12:59 ` Christoph Hellwig
2021-07-15 13:15 ` Joao Martins
2021-07-15 6:48 ` Christoph Hellwig
2021-07-15 13:15 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 05/14] mm/sparse-vmemmap: add a pgmap argument to section activation Joao Martins
2021-07-28 5:56 ` Dan Williams
2021-07-28 9:43 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 06/14] mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper Joao Martins
2021-07-28 6:04 ` Dan Williams
2021-07-28 10:48 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 07/14] mm/hugetlb_vmemmap: move comment block to Documentation/vm Joao Martins
2021-07-15 2:47 ` [External] " Muchun Song
2021-07-15 13:16 ` Joao Martins
2021-07-28 6:09 ` Dan Williams
2021-07-14 19:35 ` [PATCH v3 08/14] mm/sparse-vmemmap: populate compound pagemaps Joao Martins
2021-07-28 6:55 ` Dan Williams
2021-07-28 15:35 ` Joao Martins
2021-07-28 18:03 ` Dan Williams
2021-07-28 18:54 ` Joao Martins [this message]
2021-07-28 20:04 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 09/14] mm/page_alloc: reuse tail struct pages for " Joao Martins
2021-07-28 7:28 ` Dan Williams
2021-07-28 15:56 ` Joao Martins
2021-07-28 16:08 ` Dan Williams
2021-07-28 16:12 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 10/14] device-dax: use ALIGN() for determining pgoff Joao Martins
2021-07-28 7:29 ` Dan Williams
2021-07-28 15:56 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 11/14] device-dax: ensure dev_dax->pgmap is valid for dynamic devices Joao Martins
2021-07-28 7:30 ` Dan Williams
2021-07-28 15:56 ` Joao Martins
2021-08-06 12:28 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 12/14] device-dax: compound pagemap support Joao Martins
2021-07-14 23:36 ` Dan Williams
2021-07-15 12:00 ` Joao Martins
2021-07-27 23:51 ` Dan Williams
2021-07-28 9:36 ` Joao Martins
2021-07-28 18:51 ` Dan Williams
2021-07-28 18:59 ` Joao Martins
2021-07-28 19:03 ` Dan Williams
2021-07-14 19:35 ` [PATCH v3 13/14] mm/gup: grab head page refcount once for group of subpages Joao Martins
2021-07-28 19:55 ` Dan Williams
2021-07-28 20:07 ` Joao Martins
2021-07-28 20:23 ` Dan Williams
2021-08-25 19:10 ` Joao Martins
2021-08-25 19:15 ` Matthew Wilcox
2021-08-25 19:26 ` Joao Martins
2021-07-14 19:35 ` [PATCH v3 14/14] mm/sparse-vmemmap: improve memory savings for compound pud geometry Joao Martins
2021-07-28 20:03 ` Dan Williams
2021-07-28 20:08 ` Joao Martins
2021-07-14 21:48 ` [PATCH v3 00/14] mm, sparse-vmemmap: Introduce compound pagemaps Andrew Morton
2021-07-14 23:47 ` Dan Williams
2021-07-22 2:24 ` Matthew Wilcox
2021-07-22 10:53 ` Joao Martins
2021-07-27 23:23 ` Dan Williams
2021-08-02 10:40 ` Joao Martins
2021-08-02 14:06 ` Dan Williams
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