From: Dan Williams <dan.j.williams@intel.com>
To: Joao Martins <joao.m.martins@oracle.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 10:15:12 -0800 [thread overview]
Message-ID: <CAPcyv4gdL3p-RVKSVGPfSdBWW+eakTHqCYZp2hqV4QiXCv6KTw@mail.gmail.com> (raw)
In-Reply-To: <1cf0adb0-9692-bcb2-4d3d-374ba3164994@oracle.com>
On Tue, Feb 23, 2021 at 9:16 AM Joao Martins <joao.m.martins@oracle.com> wrote:
>
> On 2/23/21 4:44 PM, Dan Williams wrote:
> > On Tue, Feb 23, 2021 at 8:30 AM Joao Martins <joao.m.martins@oracle.com> wrote:
> >>
> >> 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?
> >>
> >
> > Good catch.
> >
> > Must have been an oversight of the conversion. FOLL_LONGTERM collides
> > with filesystem operations, but not device-dax.
>
> hmmmm, fwiw, it was unilaterally disabled for any devmap pmd/pud in commit 7af75561e171
> ("mm/gup: add FOLL_LONGTERM capability to GUP fast") and I must only assume that
> by "DAX pages" the submitter was only referring to fs-dax pages.
Agree, that was an fsdax only assumption. Maybe this went unnoticed
because the primary gup-fast case for direct-I/O was not impacted.
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WARNING: multiple messages have this Message-ID (diff)
From: Dan Williams <dan.j.williams@intel.com>
To: Joao Martins <joao.m.martins@oracle.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 10:15:12 -0800 [thread overview]
Message-ID: <CAPcyv4gdL3p-RVKSVGPfSdBWW+eakTHqCYZp2hqV4QiXCv6KTw@mail.gmail.com> (raw)
In-Reply-To: <1cf0adb0-9692-bcb2-4d3d-374ba3164994@oracle.com>
On Tue, Feb 23, 2021 at 9:16 AM Joao Martins <joao.m.martins@oracle.com> wrote:
>
> On 2/23/21 4:44 PM, Dan Williams wrote:
> > On Tue, Feb 23, 2021 at 8:30 AM Joao Martins <joao.m.martins@oracle.com> wrote:
> >>
> >> 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?
> >>
> >
> > Good catch.
> >
> > Must have been an oversight of the conversion. FOLL_LONGTERM collides
> > with filesystem operations, but not device-dax.
>
> hmmmm, fwiw, it was unilaterally disabled for any devmap pmd/pud in commit 7af75561e171
> ("mm/gup: add FOLL_LONGTERM capability to GUP fast") and I must only assume that
> by "DAX pages" the submitter was only referring to fs-dax pages.
Agree, that was an fsdax only assumption. Maybe this went unnoticed
because the primary gup-fast case for direct-I/O was not impacted.
next prev parent reply other threads:[~2021-02-23 18:15 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
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 [this message]
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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