From: Bob Liu <bob.liu@oracle.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Bob Liu <lliubbo@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave@sr71.net>, David Airlie <airlied@linux.ie>,
Dave Hansen <dave.hansen@linux.intel.com>,
Dave Chinner <david@fromorbit.com>, Linux-MM <linux-mm@kvack.org>,
"H. Peter Anvin" <hpa@zytor.com>, Christoph Hellwig <hch@lst.de>,
Andrea Arcangeli <aarcange@redhat.com>,
kbuild test robot <lkp@intel.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
X86 ML <x86@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Mel Gorman <mgorman@suse.de>,
Matthew Wilcox <willy@linux.intel.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Christoffer Dall <christoffer.dall@linaro.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Logan Gunthorpe <logang@deltatee.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [-mm PATCH v4 00/18] get_user_pages() for dax pte and pmd mappings
Date: Tue, 29 Dec 2015 11:23:26 +0800 [thread overview]
Message-ID: <5681FCAE.4060208@oracle.com> (raw)
In-Reply-To: <CAPcyv4j5QRAy-pM=TcCVrY8tH8H7iOL36KojZOeHKuLdBOcwDg@mail.gmail.com>
On 12/28/2015 02:55 AM, Dan Williams wrote:
> On Sun, Dec 27, 2015 at 12:33 AM, Bob Liu <lliubbo@gmail.com> wrote:
>> Hey Dan,
>>
> [..]
>> What about space for page tables?
>> Page tables(mapping all memory in PMEM to virtual address space) may
>> also consume significantly DRAM space if huge page is not enabled or
>> split.
>> Should we also consider to allocate pte page tables from PMEM in future?
>
> On x86_64 these ranges are covered by gigabyte pages by default (see
> init_memory_mapping()). I don't see much incremental benefit from
> allocating pte's from pmem.
>
Oh, that's the direct mapping. I mean ptes consumed in:
__dax_fault > dax_insert_mapping > insert_pfn > __get_locked_pte
In some bad situations e.g mmap a lot of large ext4 files exist in pmem but
hugepage can't be used because of fragmentation, then the consumption of pte
page tables may can't be ignored?
Anyway, this is not a blocker of these patches.
Thanks,
Bob
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prev parent reply other threads:[~2015-12-29 3:24 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-21 5:44 [-mm PATCH v4 00/18] get_user_pages() for dax pte and pmd mappings Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 01/18] kvm: rename pfn_t to kvm_pfn_t Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 02/18] mm, dax, pmem: introduce pfn_t Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 03/18] mm: skip memory block registration for ZONE_DEVICE Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 04/18] mm: introduce find_dev_pagemap() Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 05/18] x86, mm: introduce vmem_altmap to augment vmemmap_populate() Dan Williams
2015-12-27 8:40 ` Bob Liu
2015-12-21 5:44 ` [-mm PATCH v4 06/18] libnvdimm, pfn, pmem: allocate memmap array in persistent memory Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 07/18] avr32: convert to asm-generic/memory_model.h Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 08/18] hugetlb: fix compile error on tile Dan Williams
2015-12-21 5:44 ` [-mm PATCH v4 09/18] frv: fix compiler warning from definition of __pmd() Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 10/18] x86, mm: introduce _PAGE_DEVMAP Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 11/18] mm, dax, gpu: convert vm_insert_mixed to pfn_t Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 12/18] mm, dax: convert vmf_insert_pfn_pmd() " Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 13/18] libnvdimm, pmem: move request_queue allocation earlier in probe Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 14/18] mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup Dan Williams
2015-12-27 8:46 ` Bob Liu
2015-12-27 19:02 ` Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 15/18] mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd Dan Williams
2015-12-25 0:59 ` [-mm PATCH v5 " Dan Williams
2015-12-25 1:11 ` Sasha Levin
2015-12-30 5:32 ` [-mm PATCH v4 " Williams, Dan J
2015-12-21 5:45 ` [-mm PATCH v4 16/18] mm, x86: get_user_pages() for dax mappings Dan Williams
2015-12-25 1:03 ` [-mm PATCH v5 " Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 17/18] dax: provide diagnostics for pmd mapping failures Dan Williams
2015-12-21 5:45 ` [-mm PATCH v4 18/18] dax: re-enable dax pmd mappings Dan Williams
2015-12-27 8:33 ` [-mm PATCH v4 00/18] get_user_pages() for dax pte and " Bob Liu
2015-12-27 18:55 ` Dan Williams
2015-12-29 3:23 ` Bob Liu [this message]
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