€•õ+      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/mm/swap-table”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$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/zh_TW/mm/swap-table”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/it_IT/mm/swap-table”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/ja_JP/mm/swap-table”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/ko_KR/mm/swap-table”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/sp_SP/mm/swap-table”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”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$]”h&]”Œ	xml:space”Œpreserve”uh1h¡hhhžhhŸŒ;/var/lib/git/docbuild/linux/Documentation/mm/swap-table.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ
Swap Table”h]”hŒ
Swap Table”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h KubhŒ	paragraph”“”)”}”(hŒISwap table implements swap cache as a per-cluster swap cache value array.”h]”hŒISwap table implements swap cache as a per-cluster swap cache value array.”…””}”(hhËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K	hh¶hžhubhµ)”}”(hhh]”(hº)”}”(hŒ
Swap Entry”h]”hŒ
Swap Entry”…””}”(hhÜhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hhÙhžhhŸh³h KubhÊ)”}”(hŒQA swap entry contains the information required to serve the anonymous page
fault.”h]”hŒQA swap entry contains the information required to serve the anonymous page
fault.”…””}”(hhêhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhhÙhžhubhÊ)”}”(hŒ>Swap entry is encoded as two parts: swap type and swap offset.”h]”hŒ>Swap entry is encoded as two parts: swap type and swap offset.”…””}”(hhøhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhhÙhžhubhÊ)”}”(hŒ|The swap type indicates which swap device to use.
The swap offset is the offset of the swap file to read the page data from.”h]”hŒ|The swap type indicates which swap device to use.
The swap offset is the offset of the swap file to read the page data from.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhhÙhžhubeh}”(h]”Œ
swap-entry”ah ]”h"]”Œ
swap entry”ah$]”h&]”uh1h´hh¶hžhhŸh³h Kubhµ)”}”(hhh]”(hº)”}”(hŒ
Swap Cache”h]”hŒ
Swap Cache”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj  hžhhŸh³h KubhÊ)”}”(hŒ¥Swap cache is a map to look up folios using swap entry as the key. The result
value can have three possible types depending on which stage of this swap entry
was in.”h]”hŒ¥Swap cache is a map to look up folios using swap entry as the key. The result
value can have three possible types depending on which stage of this swap entry
was in.”…””}”(hj-  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj  hžhubhŒenumerated_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒ#NULL: This swap entry is not used.
”h]”hÊ)”}”(hŒ"NULL: This swap entry is not used.”h]”hŒ"NULL: This swap entry is not used.”…””}”(hjF  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhjB  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j@  hj=  hžhhŸh³h NubjA  )”}”(hŒ®folio: A folio has been allocated and bound to this swap entry. This is
the transient state of swap out or swap in. The folio data can be in
the folio or swap file, or both.
”h]”hÊ)”}”(hŒ­folio: A folio has been allocated and bound to this swap entry. This is
the transient state of swap out or swap in. The folio data can be in
the folio or swap file, or both.”h]”hŒ­folio: A folio has been allocated and bound to this swap entry. This is
the transient state of swap out or swap in. The folio data can be in
the folio or swap file, or both.”…””}”(hj^  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhjZ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j@  hj=  hžhhŸh³h NubjA  )”}”(hŒƒshadow: The shadow contains the working set information of the swapped
out folio. This is the normal state for a swapped out page.
”h]”hÊ)”}”(hŒ‚shadow: The shadow contains the working set information of the swapped
out folio. This is the normal state for a swapped out page.”h]”hŒ‚shadow: The shadow contains the working set information of the swapped
out folio. This is the normal state for a swapped out page.”…””}”(hjv  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K#hjr  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j@  hj=  hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œarabic”Œprefix”hŒsuffix”Œ.”uh1j;  hj  hžhhŸh³h Kubeh}”(h]”Œ
swap-cache”ah ]”h"]”Œ
swap cache”ah$]”h&]”uh1h´hh¶hžhhŸh³h Kubhµ)”}”(hhh]”(hº)”}”(hŒSwap Table Internals”h]”hŒSwap Table Internals”…””}”(hj   hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj  hžhhŸh³h K'ubhÊ)”}”(hŒThe previous swap cache is implemented by XArray. The XArray is a tree
structure. Each lookup will go through multiple nodes. Can we do better?”h]”hŒThe previous swap cache is implemented by XArray. The XArray is a tree
structure. Each lookup will go through multiple nodes. Can we do better?”…””}”(hj®  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K)hj  hžhubhÊ)”}”(hŒ±Notice that most of the time when we look up the swap cache, we are either
in a swap in or swap out path. We should already have the swap cluster,
which contains the swap entry.”h]”hŒ±Notice that most of the time when we look up the swap cache, we are either
in a swap in or swap out path. We should already have the swap cluster,
which contains the swap entry.”…””}”(hj¼  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K,hj  hžhubhÊ)”}”(hŒIf we have a per-cluster array to store swap cache value in the cluster.
Swap cache lookup within the cluster can be a very simple array lookup.”h]”hŒIf we have a per-cluster array to store swap cache value in the cluster.
Swap cache lookup within the cluster can be a very simple array lookup.”…””}”(hjÊ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K0hj  hžhubhÊ)”}”(hŒIWe give such a per-cluster swap cache value array a name: the swap table.”h]”hŒIWe give such a per-cluster swap cache value array a name: the swap table.”…””}”(hjØ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K3hj  hžhubhÊ)”}”(hŒËA swap table is an array of pointers. Each pointer is the same size as a
PTE. The size of a swap table for one swap cluster typically matches a PTE
page table, which is one page on modern 64-bit systems.”h]”hŒËA swap table is an array of pointers. Each pointer is the same size as a
PTE. The size of a swap table for one swap cluster typically matches a PTE
page table, which is one page on modern 64-bit systems.”…””}”(hjæ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K5hj  hžhubhÊ)”}”(hŒSWith swap table, swap cache lookup can achieve great locality, simpler,
and faster.”h]”hŒSWith swap table, swap cache lookup can achieve great locality, simpler,
and faster.”…””}”(hjô  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K9hj  hžhubeh}”(h]”Œswap-table-internals”ah ]”h"]”Œswap table internals”ah$]”h&]”uh1h´hh¶hžhhŸh³h K'ubhµ)”}”(hhh]”(hº)”}”(hŒLocking”h]”hŒLocking”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj
  hžhhŸh³h K=ubhÊ)”}”(hŒéSwap table modification requires taking the cluster lock. If a folio
is being added to or removed from the swap table, the folio must be
locked prior to the cluster lock. After adding or removing is done, the
folio shall be unlocked.”h]”hŒéSwap table modification requires taking the cluster lock. If a folio
is being added to or removed from the swap table, the folio must be
locked prior to the cluster lock. After adding or removing is done, the
folio shall be unlocked.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K?hj
  hžhubhÊ)”}”(hŒ~Swap table lookup is protected by RCU and atomic read. If the lookup
returns a folio, the user must lock the folio before use.”h]”hŒ~Swap table lookup is protected by RCU and atomic read. If the lookup
returns a folio, the user must lock the folio before use.”…””}”(hj)  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KDhj
  hžhubeh}”(h]”Œlocking”ah ]”h"]”Œlocking”ah$]”h&]”uh1h´hh¶hžhhŸh³h K=ubeh}”(h]”Œ
swap-table”ah ]”h"]”Œ
swap table”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”jj  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”}”(jD  jA  j  j  jš  j—  j  j  j<  j9  uŒ	nametypes”}”(jD  ‰j  ‰jš  ‰j  ‰j<  ‰uh}”(jA  h¶j  hÙj—  j  j  j  j9  j
  uŒ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
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