From: Joao Martins <joao.m.martins@oracle.com> To: Dan Williams <dan.j.williams@intel.com> Cc: Linux MM <linux-mm@kvack.org>, linux-nvdimm <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> Subject: Re: [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps Date: Tue, 23 Feb 2021 16:28:57 +0000 [thread overview] Message-ID: <6a18179e-65f7-367d-89a9-d5162f10fef0@oracle.com> (raw) In-Reply-To: <CAPcyv4gQQ03-nhBNwLK6KDc953SVD1rOs7HFBo_Mu9LFTkXRgw@mail.gmail.com> On 2/20/21 1:18 AM, Dan Williams wrote: > On Tue, Dec 8, 2020 at 9:32 AM Joao Martins <joao.m.martins@oracle.com> wrote: >> Patch 6 - 8: Optimize grabbing/release a page refcount changes given that we >> are working with compound pages i.e. we do 1 increment/decrement to the head >> page for a given set of N subpages compared as opposed to N individual writes. >> {get,pin}_user_pages_fast() for zone_device with compound pagemap consequently >> improves considerably, and unpin_user_pages() improves as well when passed a >> set of consecutive pages: >> >> before after >> (get_user_pages_fast 1G;2M page size) ~75k us -> ~3.2k ; ~5.2k us >> (pin_user_pages_fast 1G;2M page size) ~125k us -> ~3.4k ; ~5.5k us > > Compelling! > BTW is there any reason why we don't support pin_user_pages_fast() with FOLL_LONGTERM for device-dax? Looking at the history, I understand that fsdax can't support it atm, but I am not sure that the same holds for device-dax. I have this small chunk (see below the scissors mark) which relaxes this for a pgmap of type MEMORY_DEVICE_GENERIC, albeit not sure if there is a fundamental issue for the other types that makes this an unwelcoming change. Joao --------------------->8--------------------- Subject: [PATCH] mm/gup: allow FOLL_LONGTERM pin-fast for MEMORY_DEVICE_GENERIC The downside would be one extra lookup in dev_pagemap tree for other pgmap->types (P2P, FSDAX, PRIVATE). But just one per gup-fast() call. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- include/linux/mm.h | 5 +++++ mm/gup.c | 24 +++++++++++++----------- 2 files changed, 18 insertions(+), 11 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 32f0c3986d4f..c89a049bbd7a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1171,6 +1171,11 @@ static inline bool is_pci_p2pdma_page(const struct page *page) page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA; } +static inline bool devmap_longterm_available(const struct dev_pagemap *pgmap) +{ + return pgmap->type == MEMORY_DEVICE_GENERIC; +} + /* 127: arbitrary random number, small enough to assemble well */ #define page_ref_zero_or_close_to_overflow(page) \ ((unsigned int) page_ref_count(page) + 127u <= 127u) diff --git a/mm/gup.c b/mm/gup.c index 222d1fdc5cfa..03e370d360e6 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2092,14 +2092,18 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, goto pte_unmap; if (pte_devmap(pte)) { - if (unlikely(flags & FOLL_LONGTERM)) - goto pte_unmap; - pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); if (unlikely(!pgmap)) { undo_dev_pagemap(nr, nr_start, flags, pages); goto pte_unmap; } + + if (unlikely(flags & FOLL_LONGTERM) && + !devmap_longterm_available(pgmap)) { + undo_dev_pagemap(nr, nr_start, flags, pages); + goto pte_unmap; + } + } else if (pte_special(pte)) goto pte_unmap; @@ -2195,6 +2199,10 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, return 0; } + if (unlikely(flags & FOLL_LONGTERM) && + !devmap_longterm_available(pgmap)) + return 0; + @@ -2356,12 +2364,9 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, if (!pmd_access_permitted(orig, flags & FOLL_WRITE)) return 0; - if (pmd_devmap(orig)) { - if (unlikely(flags & FOLL_LONGTERM)) - return 0; + if (pmd_devmap(orig)) return __gup_device_huge_pmd(orig, pmdp, addr, end, flags, pages, nr); - } page = pmd_page(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); refs = record_subpages(page, addr, end, pages + *nr); @@ -2390,12 +2395,9 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, if (!pud_access_permitted(orig, flags & FOLL_WRITE)) return 0; - if (pud_devmap(orig)) { - if (unlikely(flags & FOLL_LONGTERM)) - return 0; + if (pud_devmap(orig)) return __gup_device_huge_pud(orig, pudp, addr, end, flags, pages, nr); - } page = pud_page(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); refs = record_subpages(page, addr, end, pages + *nr); -- 2.17.1 _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
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From: Joao Martins <joao.m.martins@oracle.com> To: Dan Williams <dan.j.williams@intel.com> Cc: Linux MM <linux-mm@kvack.org>, Ira Weiny <ira.weiny@intel.com>, linux-nvdimm <linux-nvdimm@lists.01.org>, Matthew Wilcox <willy@infradead.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 RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps Date: Tue, 23 Feb 2021 16:28:57 +0000 [thread overview] Message-ID: <6a18179e-65f7-367d-89a9-d5162f10fef0@oracle.com> (raw) In-Reply-To: <CAPcyv4gQQ03-nhBNwLK6KDc953SVD1rOs7HFBo_Mu9LFTkXRgw@mail.gmail.com> On 2/20/21 1:18 AM, Dan Williams wrote: > On Tue, Dec 8, 2020 at 9:32 AM Joao Martins <joao.m.martins@oracle.com> wrote: >> Patch 6 - 8: Optimize grabbing/release a page refcount changes given that we >> are working with compound pages i.e. we do 1 increment/decrement to the head >> page for a given set of N subpages compared as opposed to N individual writes. >> {get,pin}_user_pages_fast() for zone_device with compound pagemap consequently >> improves considerably, and unpin_user_pages() improves as well when passed a >> set of consecutive pages: >> >> before after >> (get_user_pages_fast 1G;2M page size) ~75k us -> ~3.2k ; ~5.2k us >> (pin_user_pages_fast 1G;2M page size) ~125k us -> ~3.4k ; ~5.5k us > > Compelling! > BTW is there any reason why we don't support pin_user_pages_fast() with FOLL_LONGTERM for device-dax? Looking at the history, I understand that fsdax can't support it atm, but I am not sure that the same holds for device-dax. I have this small chunk (see below the scissors mark) which relaxes this for a pgmap of type MEMORY_DEVICE_GENERIC, albeit not sure if there is a fundamental issue for the other types that makes this an unwelcoming change. Joao --------------------->8--------------------- Subject: [PATCH] mm/gup: allow FOLL_LONGTERM pin-fast for MEMORY_DEVICE_GENERIC The downside would be one extra lookup in dev_pagemap tree for other pgmap->types (P2P, FSDAX, PRIVATE). But just one per gup-fast() call. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- include/linux/mm.h | 5 +++++ mm/gup.c | 24 +++++++++++++----------- 2 files changed, 18 insertions(+), 11 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 32f0c3986d4f..c89a049bbd7a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1171,6 +1171,11 @@ static inline bool is_pci_p2pdma_page(const struct page *page) page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA; } +static inline bool devmap_longterm_available(const struct dev_pagemap *pgmap) +{ + return pgmap->type == MEMORY_DEVICE_GENERIC; +} + /* 127: arbitrary random number, small enough to assemble well */ #define page_ref_zero_or_close_to_overflow(page) \ ((unsigned int) page_ref_count(page) + 127u <= 127u) diff --git a/mm/gup.c b/mm/gup.c index 222d1fdc5cfa..03e370d360e6 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2092,14 +2092,18 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, goto pte_unmap; if (pte_devmap(pte)) { - if (unlikely(flags & FOLL_LONGTERM)) - goto pte_unmap; - pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); if (unlikely(!pgmap)) { undo_dev_pagemap(nr, nr_start, flags, pages); goto pte_unmap; } + + if (unlikely(flags & FOLL_LONGTERM) && + !devmap_longterm_available(pgmap)) { + undo_dev_pagemap(nr, nr_start, flags, pages); + goto pte_unmap; + } + } else if (pte_special(pte)) goto pte_unmap; @@ -2195,6 +2199,10 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, return 0; } + if (unlikely(flags & FOLL_LONGTERM) && + !devmap_longterm_available(pgmap)) + return 0; + @@ -2356,12 +2364,9 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, if (!pmd_access_permitted(orig, flags & FOLL_WRITE)) return 0; - if (pmd_devmap(orig)) { - if (unlikely(flags & FOLL_LONGTERM)) - return 0; + if (pmd_devmap(orig)) return __gup_device_huge_pmd(orig, pmdp, addr, end, flags, pages, nr); - } page = pmd_page(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); refs = record_subpages(page, addr, end, pages + *nr); @@ -2390,12 +2395,9 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, if (!pud_access_permitted(orig, flags & FOLL_WRITE)) return 0; - if (pud_devmap(orig)) { - if (unlikely(flags & FOLL_LONGTERM)) - return 0; + if (pud_devmap(orig)) return __gup_device_huge_pud(orig, pudp, addr, end, flags, pages, nr); - } page = pud_page(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); refs = record_subpages(page, addr, end, pages + *nr); -- 2.17.1
next prev parent reply other threads:[~2021-02-23 16:29 UTC|newest] Thread overview: 147+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-08 17:28 [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 1/9] memremap: add ZONE_DEVICE support for compound pages Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-09 5:59 ` John Hubbard 2020-12-09 5:59 ` John Hubbard 2020-12-09 6:33 ` Matthew Wilcox 2020-12-09 6:33 ` Matthew Wilcox 2020-12-09 13:12 ` Joao Martins 2020-12-09 13:12 ` Joao Martins 2021-02-20 1:43 ` Dan Williams 2021-02-20 1:43 ` Dan Williams 2021-02-22 11:24 ` Joao Martins 2021-02-22 11:24 ` Joao Martins 2021-02-22 20:37 ` Dan Williams 2021-02-22 20:37 ` Dan Williams 2021-02-23 15:46 ` Joao Martins 2021-02-23 15:46 ` Joao Martins 2021-02-23 16:50 ` Dan Williams 2021-02-23 16:50 ` Dan Williams 2021-02-23 17:18 ` Joao Martins 2021-02-23 17:18 ` Joao Martins 2021-02-23 18:18 ` Dan Williams 2021-02-23 18:18 ` Dan Williams 2021-03-10 18:12 ` Joao Martins 2021-03-10 18:12 ` Joao Martins 2021-03-12 5:54 ` Dan Williams 2021-03-12 5:54 ` Dan Williams 2021-02-20 1:24 ` Dan Williams 2021-02-20 1:24 ` Dan Williams 2021-02-22 11:09 ` Joao Martins 2021-02-22 11:09 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 2/9] sparse-vmemmap: Consolidate arguments in vmemmap section populate Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-09 6:16 ` John Hubbard 2020-12-09 6:16 ` John Hubbard 2020-12-09 13:51 ` Joao Martins 2020-12-09 13:51 ` Joao Martins 2021-02-20 1:49 ` Dan Williams 2021-02-20 1:49 ` Dan Williams 2021-02-22 11:26 ` Joao Martins 2021-02-22 11:26 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 3/9] sparse-vmemmap: Reuse vmemmap areas for a given mhp_params::align Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-08 17:38 ` Joao Martins 2020-12-08 17:38 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 3/9] sparse-vmemmap: Reuse vmemmap areas for a given page size Joao Martins 2020-12-08 17:28 ` Joao Martins 2021-02-20 3:34 ` Dan Williams 2021-02-20 3:34 ` Dan Williams 2021-02-22 11:42 ` Joao Martins 2021-02-22 11:42 ` Joao Martins 2021-02-22 22:40 ` Dan Williams 2021-02-22 22:40 ` Dan Williams 2021-02-23 15:46 ` Joao Martins 2021-02-23 15:46 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 4/9] mm/page_alloc: Reuse tail struct pages for compound pagemaps Joao Martins 2020-12-08 17:28 ` Joao Martins 2021-02-20 6:17 ` Dan Williams 2021-02-20 6:17 ` Dan Williams 2021-02-22 12:01 ` Joao Martins 2021-02-22 12:01 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 5/9] device-dax: Compound pagemap support Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 6/9] mm/gup: Grab head page refcount once for group of subpages Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-08 19:49 ` Jason Gunthorpe 2020-12-09 11:05 ` Joao Martins 2020-12-09 11:05 ` Joao Martins 2020-12-09 15:15 ` Jason Gunthorpe 2020-12-09 16:02 ` Joao Martins 2020-12-09 16:02 ` Joao Martins 2020-12-09 16:24 ` Jason Gunthorpe 2020-12-09 17:27 ` Joao Martins 2020-12-09 17:27 ` Joao Martins 2020-12-09 18:14 ` Matthew Wilcox 2020-12-09 18:14 ` Matthew Wilcox 2020-12-09 19:08 ` Jason Gunthorpe 2020-12-10 15:43 ` Joao Martins 2020-12-10 15:43 ` Joao Martins 2020-12-09 4:40 ` John Hubbard 2020-12-09 4:40 ` John Hubbard 2020-12-09 13:44 ` Joao Martins 2020-12-09 13:44 ` Joao Martins 2020-12-08 17:28 ` [PATCH RFC 7/9] mm/gup: Decrement head page " Joao Martins 2020-12-08 17:28 ` Joao Martins 2020-12-08 19:34 ` Jason Gunthorpe 2020-12-09 5:06 ` John Hubbard 2020-12-09 5:06 ` John Hubbard 2020-12-09 13:43 ` Jason Gunthorpe 2020-12-09 12:17 ` Joao Martins 2020-12-09 12:17 ` Joao Martins 2020-12-17 19:05 ` Joao Martins 2020-12-17 19:05 ` Joao Martins 2020-12-17 20:05 ` Jason Gunthorpe 2020-12-17 22:34 ` Joao Martins 2020-12-17 22:34 ` Joao Martins 2020-12-18 14:25 ` Jason Gunthorpe 2020-12-19 2:06 ` John Hubbard 2020-12-19 2:06 ` John Hubbard 2020-12-19 13:10 ` Joao Martins 2020-12-19 13:10 ` Joao Martins 2020-12-08 17:29 ` [PATCH RFC 8/9] RDMA/umem: batch page unpin in __ib_mem_release() Joao Martins 2020-12-08 17:29 ` Joao Martins 2020-12-08 19:29 ` Jason Gunthorpe 2020-12-09 10:59 ` Joao Martins 2020-12-09 10:59 ` Joao Martins 2020-12-19 13:15 ` Joao Martins 2020-12-19 13:15 ` Joao Martins 2020-12-09 5:18 ` John Hubbard 2020-12-09 5:18 ` John Hubbard 2020-12-08 17:29 ` [PATCH RFC 9/9] mm: Add follow_devmap_page() for devdax vmas Joao Martins 2020-12-08 17:29 ` Joao Martins 2020-12-08 19:57 ` Jason Gunthorpe 2020-12-09 8:05 ` Christoph Hellwig 2020-12-09 8:05 ` Christoph Hellwig 2020-12-09 11:19 ` Joao Martins 2020-12-09 11:19 ` Joao Martins 2020-12-09 5:23 ` John Hubbard 2020-12-09 5:23 ` John Hubbard 2020-12-09 9:38 ` [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps David Hildenbrand 2020-12-09 9:38 ` David Hildenbrand 2020-12-09 9:52 ` [External] " Muchun Song 2020-12-09 9:52 ` Muchun Song 2021-02-20 1:18 ` Dan Williams 2021-02-20 1:18 ` Dan Williams 2021-02-22 11:06 ` Joao Martins 2021-02-22 11:06 ` Joao Martins 2021-02-22 14:32 ` Joao Martins 2021-02-22 14:32 ` Joao Martins 2021-02-23 16:28 ` Joao Martins [this message] 2021-02-23 16:28 ` Joao Martins 2021-02-23 16:44 ` Dan Williams 2021-02-23 16:44 ` Dan Williams 2021-02-23 17:15 ` Joao Martins 2021-02-23 17:15 ` Joao Martins 2021-02-23 18:15 ` Dan Williams 2021-02-23 18:15 ` Dan Williams 2021-02-23 18:54 ` Jason Gunthorpe 2021-02-23 22:48 ` Dan Williams 2021-02-23 22:48 ` Dan Williams 2021-02-23 23:07 ` Jason Gunthorpe 2021-02-24 0:14 ` Dan Williams 2021-02-24 0:14 ` Dan Williams 2021-02-24 1:00 ` Jason Gunthorpe 2021-02-24 1:32 ` Dan Williams 2021-02-24 1:32 ` Dan Williams
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