€•{F      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ./translations/zh_CN/arch/powerpc/vmemmap_dedup”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/zh_TW/arch/powerpc/vmemmap_dedup”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/it_IT/arch/powerpc/vmemmap_dedup”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ja_JP/arch/powerpc/vmemmap_dedup”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ko_KR/arch/powerpc/vmemmap_dedup”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/sp_SP/arch/powerpc/vmemmap_dedup”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh£sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1h¡hhhžhhŸŒH/var/lib/git/docbuild/linux/Documentation/arch/powerpc/vmemmap_dedup.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ
Device DAX”h]”hŒ
Device DAX”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h KubhŒ	paragraph”“”)”}”(hŒnThe device-dax interface uses the tail deduplication technique explained in
Documentation/mm/vmemmap_dedup.rst”h]”hŒnThe device-dax interface uses the tail deduplication technique explained in
Documentation/mm/vmemmap_dedup.rst”…””}”(hhËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒ­On powerpc, vmemmap deduplication is only used with radix MMU translation. Also
with a 64K page size, only the devdax namespace with 1G alignment uses vmemmap
deduplication.”h]”hŒ­On powerpc, vmemmap deduplication is only used with radix MMU translation. Also
with a 64K page size, only the devdax namespace with 1G alignment uses vmemmap
deduplication.”…””}”(hhÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K
hh¶hžhubhÊ)”}”(hŒ¾With 2M PMD level mapping, we require 32 struct pages and a single 64K vmemmap
page can contain 1024 struct pages (64K/sizeof(struct page)). Hence there is no
vmemmap deduplication possible.”h]”hŒ¾With 2M PMD level mapping, we require 32 struct pages and a single 64K vmemmap
page can contain 1024 struct pages (64K/sizeof(struct page)). Hence there is no
vmemmap deduplication possible.”…””}”(hhçhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒéWith 1G PUD level mapping, we require 16384 struct pages and a single 64K
vmemmap page can contain 1024 struct pages (64K/sizeof(struct page)). Hence we
require 16 64K pages in vmemmap to map the struct page for 1G PUD level mapping.”h]”hŒéWith 1G PUD level mapping, we require 16384 struct pages and a single 64K
vmemmap page can contain 1024 struct pages (64K/sizeof(struct page)). Hence we
require 16 64K pages in vmemmap to map the struct page for 1G PUD level mapping.”…””}”(hhõhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhŒdefinition_list”“”)”}”(hhh]”hŒdefinition_list_item”“”)”}”(hX{  Here's how things look like on device-dax after the sections are populated::
+-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PUD    |                     +-----------+                       | | |
|   level   |                     |     .     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     .     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |     15    | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+

”h]”(hŒterm”“”)”}”(hŒLHere's how things look like on device-dax after the sections are populated::”h]”hŒNHereâ€™s how things look like on device-dax after the sections are populated::”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hŸh³h K,hj
  ubhŒ
definition”“”)”}”(hhh]”hÊ)”}”(hX,  +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PUD    |                     +-----------+                       | | |
|   level   |                     |     .     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     .     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |     15    | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+”h]”hX,  +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PUD    |                     +-----------+                       | | |
|   level   |                     |     .     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     .     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |     15    | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+”…””}”(hj#  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj   ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj
  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  hŸh³h K,hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hh¶hžhhŸh³h NubhÊ)”}”(hŒèWith 4K page size, 2M PMD level mapping requires 512 struct pages and a single
4K vmemmap page contains 64 struct pages(4K/sizeof(struct page)). Hence we
require 8 4K pages in vmemmap to map the struct page for 2M pmd level mapping.”h]”hŒèWith 4K page size, 2M PMD level mapping requires 512 struct pages and a single
4K vmemmap page contains 64 struct pages(4K/sizeof(struct page)). Hence we
require 8 4K pages in vmemmap to map the struct page for 2M pmd level mapping.”…””}”(hjC  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K.hh¶hžhubhÊ)”}”(hŒLHere's how things look like on device-dax after the sections are populated::”h]”hŒMHereâ€™s how things look like on device-dax after the sections are populated:”…””}”(hjQ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K2hh¶hžhubhŒliteral_block”“”)”}”(hX,  +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PMD    |                     +-----------+                       | | |
|   level   |                     |     5     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     6     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |     7     | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+”h]”hX,  +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PMD    |                     +-----------+                       | | |
|   level   |                     |     5     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     6     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |     7     | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+”…””}”hja  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j_  hŸh³h K4hh¶hžhubhÊ)”}”(hŒèWith 1G PUD level mapping, we require 262144 struct pages and a single 4K
vmemmap page can contain 64 struct pages (4K/sizeof(struct page)). Hence we
require 4096 4K pages in vmemmap to map the struct pages for 1G PUD level
mapping.”h]”hŒèWith 1G PUD level mapping, we require 262144 struct pages and a single 4K
vmemmap page can contain 64 struct pages (4K/sizeof(struct page)). Hence we
require 4096 4K pages in vmemmap to map the struct pages for 1G PUD level
mapping.”…””}”(hjo  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KJhh¶hžhubhÊ)”}”(hŒLHere's how things look like on device-dax after the sections are populated::”h]”hŒMHereâ€™s how things look like on device-dax after the sections are populated:”…””}”(hj}  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KOhh¶hžhubj`  )”}”(hX,  +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PUD    |                     +-----------+                       | | |
|   level   |                     |     .     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     .     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |   4095    | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+”h]”hX,  +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
|           |                     |     0     | -------------> |     0     |
|           |                     +-----------+                +-----------+
|           |                     |     1     | -------------> |     1     |
|           |                     +-----------+                +-----------+
|           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
|           |                     +-----------+                   | | | | |
|           |                     |     3     | ------------------+ | | | |
|           |                     +-----------+                     | | | |
|           |                     |     4     | --------------------+ | | |
|    PUD    |                     +-----------+                       | | |
|   level   |                     |     .     | ----------------------+ | |
|  mapping  |                     +-----------+                         | |
|           |                     |     .     | ------------------------+ |
|           |                     +-----------+                           |
|           |                     |   4095    | --------------------------+
|           |                     +-----------+
|           |
|           |
|           |
+-----------+”…””}”hj‹  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j_  hŸh³h KQhh¶hžhubeh}”(h]”Œ
device-dax”ah ]”h"]”Œ
device dax”ah$]”h&]”uh1h´hhhžhhŸh³h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h³uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¹NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jÄ  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h³Œ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”jž  j›  sŒ	nametypes”}”jž  ‰sh}”j›  h¶sŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”hŒsystem_message”“”)”}”(hhh]”hÊ)”}”(hŒ`Blank line missing before literal block (after the "::")? Interpreted as a definition list item.”h]”hŒdBlank line missing before literal block (after the â€œ::â€)? Interpreted as a definition list item.”…””}”(hj+  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhj(  ubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”ŒINFO”Œline”K-Œsource”h³uh1j&  hj   ubaŒtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nhžhub.