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Mike Kravetz e95a985178 hugetlb: skip to end of PT page mapping when pte not present
Patch series "hugetlb: speed up linear address scanning", v2.

At unmap, fork and remap time hugetlb address ranges are linearly scanned.
We can optimize these scans if the ranges are sparsely populated.

Also, enable page table "Lazy copy" for hugetlb at fork.

NOTE: Architectures not defining CONFIG_ARCH_WANT_GENERAL_HUGETLB need to
add an arch specific version hugetlb_mask_last_page() to take advantage of
sparse address scanning improvements.  Baolin Wang added the routine for
arm64.  Other architectures which could be optimized are: ia64, mips,
parisc, powerpc, s390, sh and sparc.


This patch (of 4):

HugeTLB address ranges are linearly scanned during fork, unmap and remap
operations.  If a non-present entry is encountered, the code currently
continues to the next huge page aligned address.  However, a non-present
entry implies that the page table page for that entry is not present. 
Therefore, the linear scan can skip to the end of range mapped by the page
table page.  This can speed operations on large sparsely populated hugetlb
mappings.

Create a new routine hugetlb_mask_last_page() that will return an address
mask.  When the mask is ORed with an address, the result will be the
address of the last huge page mapped by the associated page table page. 
Use this mask to update addresses in routines which linearly scan hugetlb
address ranges when a non-present pte is encountered.

hugetlb_mask_last_page is related to the implementation of huge_pte_offset
as hugetlb_mask_last_page is called when huge_pte_offset returns NULL. 
This patch only provides a complete hugetlb_mask_last_page implementation
when CONFIG_ARCH_WANT_GENERAL_HUGETLB is defined.  Architectures which
provide their own versions of huge_pte_offset can also provide their own
version of hugetlb_mask_last_page.

Link: https://lkml.kernel.org/r/20220621235620.291305-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20220621235620.291305-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: James Houghton <jthoughton@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-17 17:14:34 -07:00
arch mm: hugetlb: kill set_huge_swap_pte_at() 2022-07-03 18:08:50 -07:00
block block: remove WARN_ON() from bd_link_disk_holder 2022-06-23 07:48:05 -06:00
certs Certs changes 2022-06-21 12:13:53 -05:00
crypto Certs changes 2022-06-21 12:13:53 -05:00
Documentation doc: proc: fix the description to THPeligible 2022-07-17 17:14:33 -07:00
drivers pagemap,pmem: introduce ->memory_failure() 2022-07-17 17:14:30 -07:00
fs mm: thp: kill __transhuge_page_enabled() 2022-07-17 17:14:33 -07:00
include hugetlb: skip to end of PT page mapping when pte not present 2022-07-17 17:14:34 -07:00
init gcc-12: disable '-Warray-bounds' universally for now 2022-06-09 10:11:12 -07:00
ipc These changes update the ipc sysctls so that they are fundamentally 2022-06-03 15:54:57 -07:00
kernel mm: shrinkers: provide shrinkers with names 2022-07-03 18:08:40 -07:00
lib lib: add support for device coherent type in test_hmm 2022-07-17 17:14:29 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm hugetlb: skip to end of PT page mapping when pte not present 2022-07-17 17:14:34 -07:00
net mm/swap: convert __put_page() to __folio_put() 2022-07-03 18:08:47 -07:00
samples fprobe, samples: Add use_trace option and show hit/missed counter 2022-06-17 21:53:29 +02:00
scripts kbuild: Ignore __this_module in gen_autoksyms.sh 2022-06-26 06:15:05 +09:00
security selinux: free contexts previously transferred in selinux_add_opt() 2022-06-15 21:20:45 -04:00
sound sound fixes for 5.19-rc4 2022-06-23 08:44:00 -05:00
tools tools: add selftests to hmm for COW in device memory 2022-07-17 17:14:29 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap mailmap: add entry for Christian Marangi 2022-06-16 19:11:32 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS docs: rename Documentation/vm to Documentation/mm 2022-06-27 12:52:53 -07:00
Makefile Linux 5.19-rc4 2022-06-26 14:22:10 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.