From: Joao Martins <joao.m.martins@oracle.com>
To: linux-mm@kvack.org
Cc: linux-nvdimm@lists.01.org, Matthew Wilcox <willy@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Joao Martins <joao.m.martins@oracle.com>
Subject: [PATCH v1 09/11] mm/page_alloc: reuse tail struct pages for compound pagemaps
Date: Thu, 25 Mar 2021 23:09:36 +0000 [thread overview]
Message-ID: <20210325230938.30752-10-joao.m.martins@oracle.com> (raw)
In-Reply-To: <20210325230938.30752-1-joao.m.martins@oracle.com>
When a pgmap @align is set, all pages are mapped at a given huge page
alignment and thus uses compound pages to describe them as opposed to a
struct per 4K.
With @align > PAGE_SIZE and when struct pages are stored in ram
(!altmap) most tail pages are reused. Consequently, the amount of unique
struct pages is a lot smaller that the total amount of struct pages
being mapped.
When struct pages are initialize in memmap_init_zone_device, make
sure that only unique struct pages are initialized i.e. the first 2
4K pages per @align which means 128 struct pages, instead of 32768 for
2M @align or 262144 for a 1G @align.
Keep old behaviour with altmap given that it doesn't support reusal
of tail vmemmap areas.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
mm/page_alloc.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3a77f9e43f3a..948dfad6754b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6277,6 +6277,8 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
}
}
+#define MEMMAP_NR_PAGES (2 * (PAGE_SIZE/sizeof(struct page)))
+
void __ref memmap_init_zone_device(struct zone *zone,
unsigned long start_pfn,
unsigned long nr_pages,
@@ -6287,6 +6289,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
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 ntails = min_t(unsigned long, pfn_align, MEMMAP_NR_PAGES);
unsigned long zone_idx = zone_idx(zone);
unsigned long start = jiffies;
int nid = pgdat->node_id;
@@ -6302,6 +6305,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
if (altmap) {
start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
nr_pages = end_pfn - start_pfn;
+ ntails = pfn_align;
}
for (pfn = start_pfn; pfn < end_pfn; pfn += pfn_align) {
@@ -6315,7 +6319,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
__SetPageHead(page);
- for (i = 1; i < pfn_align; i++) {
+ for (i = 1; i < ntails; i++) {
__init_zone_device_page(page + i, pfn + i, zone_idx,
nid, pgmap);
prep_compound_tail(page, i);
--
2.17.1
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next prev parent reply other threads:[~2021-03-25 23:10 UTC|newest]
Thread overview: 23+ 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
2021-03-25 23:09 ` [PATCH v1 02/11] mm/page_alloc: split prep_compound_page into head and tail subparts Joao Martins
2021-03-25 23:09 ` [PATCH v1 03/11] mm/page_alloc: refactor memmap_init_zone_device() page init Joao Martins
2021-03-25 23:09 ` [PATCH v1 04/11] mm/memremap: add ZONE_DEVICE support for compound pages Joao Martins
[not found] ` <CAPcyv4gs_rHL7FPqyQEb3yT4jrv8Wo_xA2ojKsppoBfmDocq8A@mail.gmail.com>
[not found] ` <cd1c9849-8660-dbdc-718a-aa4ba5d48c01@oracle.com>
[not found] ` <CAPcyv4jG8+S6xJyp=1S2=dpit0Hs2+HgGwpWeRROCRuJnQYAxQ@mail.gmail.com>
[not found] ` <56a3e271-4ef8-ba02-639e-fd7fe7de7e36@oracle.com>
[not found] ` <8c922a58-c901-1ad9-5d19-1182bd6dea1e@oracle.com>
[not found] ` <CAPcyv4j_PdzytEeabe95FrUiNVNobdJRvUE9M9j0krKQ1defBg@mail.gmail.com>
[not found] ` <e22ef769-5eb2-1812-497f-6d069d632cd0@oracle.com>
2021-06-07 21:00 ` Joao Martins
2021-06-07 21:57 ` Dan Williams
2021-03-25 23:09 ` [PATCH v1 05/11] mm/sparse-vmemmap: add a pgmap argument to section activation Joao Martins
2021-03-25 23:09 ` [PATCH v1 06/11] mm/sparse-vmemmap: refactor vmemmap_populate_basepages() Joao Martins
2021-03-25 23:09 ` [PATCH v1 07/11] mm/sparse-vmemmap: populate compound pagemaps 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 ` Joao Martins [this message]
[not found] ` <CAPcyv4gtSqfmuAaX9cs63OvLkf-h4B_5fPiEnM9p9cqLZztXpg@mail.gmail.com>
2021-06-07 13:48 ` [PATCH v1 09/11] mm/page_alloc: reuse tail struct pages for " Joao Martins
2021-06-07 19:32 ` Dan Williams
2021-06-14 18:41 ` Joao Martins
2021-06-14 23:07 ` Dan Williams
2021-03-25 23:09 ` [PATCH v1 10/11] device-dax: compound pagemap support Joao Martins
[not found] ` <CAPcyv4jeY0K7ciWeCLjxXmiWs7NNeM-_zEdZ2XAdYnyZc9PvWA@mail.gmail.com>
2021-06-07 13:59 ` Joao Martins
2021-03-25 23:09 ` [PATCH v1 11/11] mm/gup: grab head page refcount once for group of subpages Joao Martins
2021-06-02 1:05 ` Dan Williams
2021-06-07 15:21 ` Joao Martins
2021-06-07 19:22 ` Dan Williams
2021-04-01 9:38 ` [PATCH v1 00/11] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins
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