From: Matthew Wilcox <willy@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>,
Linux MM <linux-mm@kvack.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
Jason Gunthorpe <jgg@ziepe.ca>, Jane Chu <jane.chu@oracle.com>,
Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v1 04/11] mm/memremap: add ZONE_DEVICE support for compound pages
Date: Wed, 5 May 2021 19:58:54 +0100 [thread overview]
Message-ID: <20210505185854.GI1847222@casper.infradead.org> (raw)
In-Reply-To: <CAPcyv4gs_rHL7FPqyQEb3yT4jrv8Wo_xA2ojKsppoBfmDocq8A@mail.gmail.com>
On Wed, May 05, 2021 at 11:44:29AM -0700, Dan Williams wrote:
> > @@ -6285,6 +6285,8 @@ void __ref memmap_init_zone_device(struct zone *zone,
> > unsigned long pfn, end_pfn = start_pfn + nr_pages;
> > struct pglist_data *pgdat = zone->zone_pgdat;
> > struct vmem_altmap *altmap = pgmap_altmap(pgmap);
> > + unsigned int pfn_align = pgmap_pfn_align(pgmap);
> > + unsigned int order_align = order_base_2(pfn_align);
> > unsigned long zone_idx = zone_idx(zone);
> > unsigned long start = jiffies;
> > int nid = pgdat->node_id;
> > @@ -6302,10 +6304,30 @@ void __ref memmap_init_zone_device(struct zone *zone,
> > nr_pages = end_pfn - start_pfn;
> > }
> >
> > - for (pfn = start_pfn; pfn < end_pfn; pfn++) {
> > + for (pfn = start_pfn; pfn < end_pfn; pfn += pfn_align) {
>
> pfn_align is in bytes and pfn is in pages... is there a "pfn_align >>=
> PAGE_SHIFT" I missed somewhere?
If something is measured in bytes, I like to use size_t (if it's
in memory) and loff_t (if it's on storage). The compiler doesn't do
anything useful to warn you, but it's a nice indication to humans about
what's going on. And it removes the temptation to do 'pfn_align >>=
PAGE_SHIFT' and suddenly take pfn_align from being measured in bytes to
being measured in pages.
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next prev parent reply other threads:[~2021-05-05 19:00 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 23:09 [PATCH v1 00/11] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins
2021-03-25 23:09 ` [PATCH v1 01/11] memory-failure: fetch compound_head after pgmap_pfn_valid() Joao Martins
2021-04-24 0:12 ` Dan Williams
2021-04-24 19:00 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 02/11] mm/page_alloc: split prep_compound_page into head and tail subparts Joao Martins
2021-04-24 0:16 ` Dan Williams
2021-04-24 19:05 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 03/11] mm/page_alloc: refactor memmap_init_zone_device() page init Joao Martins
2021-04-24 0:18 ` Dan Williams
2021-04-24 19:05 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 04/11] mm/memremap: add ZONE_DEVICE support for compound pages Joao Martins
2021-05-05 18:44 ` Dan Williams
2021-05-05 18:58 ` Matthew Wilcox [this message]
2021-05-05 19:49 ` Joao Martins
2021-05-05 22:20 ` Dan Williams
2021-05-05 22:36 ` Joao Martins
2021-05-05 23:03 ` Dan Williams
2021-05-06 10:12 ` Joao Martins
2021-05-18 17:27 ` Joao Martins
2021-05-18 19:56 ` Jane Chu
2021-05-19 11:29 ` Joao Martins
2021-05-06 8:05 ` Aneesh Kumar K.V
2021-05-06 10:23 ` Joao Martins
2021-05-06 11:43 ` Matthew Wilcox
2021-05-06 12:15 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 05/11] mm/sparse-vmemmap: add a pgmap argument to section activation Joao Martins
2021-05-05 22:34 ` Dan Williams
2021-05-05 22:37 ` Joao Martins
2021-05-05 23:14 ` Dan Williams
2021-05-06 10:24 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 06/11] mm/sparse-vmemmap: refactor vmemmap_populate_basepages() Joao Martins
2021-05-05 22:43 ` Dan Williams
2021-05-06 10:27 ` Joao Martins
2021-05-06 18:36 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 07/11] mm/sparse-vmemmap: populate compound pagemaps Joao Martins
2021-05-06 1:18 ` Dan Williams
2021-05-06 11:01 ` Joao Martins
2021-05-10 19:19 ` Dan Williams
2021-05-13 18:45 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 08/11] mm/sparse-vmemmap: use hugepages for PUD " Joao Martins
2021-03-25 23:09 ` [PATCH v1 09/11] mm/page_alloc: reuse tail struct pages for " Joao Martins
2021-03-25 23:09 ` [PATCH v1 10/11] device-dax: compound pagemap support Joao Martins
2021-03-25 23:09 ` [PATCH v1 11/11] mm/gup: grab head page refcount once for group of subpages Joao Martins
2021-04-01 9:38 ` [PATCH v1 00/11] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins
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