€•3      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/admin-guide/cgroup-v1/pids”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$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/zh_TW/admin-guide/cgroup-v1/pids”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/it_IT/admin-guide/cgroup-v1/pids”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ja_JP/admin-guide/cgroup-v1/pids”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ko_KR/admin-guide/cgroup-v1/pids”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/sp_SP/admin-guide/cgroup-v1/pids”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒProcess Number Controller”h]”hŒProcess Number Controller”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒH/var/lib/git/docbuild/linux/Documentation/admin-guide/cgroup-v1/pids.rst”h Kubh¢)”}”(hhh]”(h§)”}”(hŒAbstract”h]”hŒAbstract”…””}”(hhºhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh·hžhhŸh¶h KubhŒ	paragraph”“”)”}”(hŒšThe process number controller is used to allow a cgroup hierarchy to stop any
new tasks from being fork()'d or clone()'d after a certain limit is reached.”h]”hŒžThe process number controller is used to allow a cgroup hierarchy to stop any
new tasks from being fork()â€™d or clone()â€™d after a certain limit is reached.”…””}”(hhÊhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhÉ)”}”(hX  Since it is trivial to hit the task limit without hitting any kmemcg limits in
place, PIDs are a fundamental resource. As such, PID exhaustion must be
preventable in the scope of a cgroup hierarchy by allowing resource limiting of
the number of tasks in a cgroup.”h]”hX  Since it is trivial to hit the task limit without hitting any kmemcg limits in
place, PIDs are a fundamental resource. As such, PID exhaustion must be
preventable in the scope of a cgroup hierarchy by allowing resource limiting of
the number of tasks in a cgroup.”…””}”(hhØhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubeh}”(h]”Œabstract”ah ]”h"]”Œabstract”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒUsage”h]”hŒUsage”…””}”(hhñhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hhîhžhhŸh¶h KubhÉ)”}”(hŒÜIn order to use the `pids` controller, set the maximum number of tasks in
pids.max (this is not available in the root cgroup for obvious reasons). The
number of processes currently in the cgroup is given by pids.current.”h]”(hŒIn order to use the ”…””}”(hhÿhžhhŸNh NubhŒtitle_reference”“”)”}”(hŒ`pids`”h]”hŒpids”…””}”(hj	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hhÿubhŒÂ controller, set the maximum number of tasks in
pids.max (this is not available in the root cgroup for obvious reasons). The
number of processes currently in the cgroup is given by pids.current.”…””}”(hhÿhžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KhhîhžhubhÉ)”}”(hXÓ  Organisational operations are not blocked by cgroup policies, so it is possible
to have pids.current > pids.max. This can be done by either setting the limit to
be smaller than pids.current, or attaching enough processes to the cgroup such
that pids.current > pids.max. However, it is not possible to violate a cgroup
policy through fork() or clone(). fork() and clone() will return -EAGAIN if the
creation of a new process would cause a cgroup policy to be violated.”h]”hXÓ  Organisational operations are not blocked by cgroup policies, so it is possible
to have pids.current > pids.max. This can be done by either setting the limit to
be smaller than pids.current, or attaching enough processes to the cgroup such
that pids.current > pids.max. However, it is not possible to violate a cgroup
policy through fork() or clone(). fork() and clone() will return -EAGAIN if the
creation of a new process would cause a cgroup policy to be violated.”…””}”(hj!  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KhhîhžhubhÉ)”}”(hŒÃTo set a cgroup to have no limit, set pids.max to "max". This is the default for
all new cgroups (N.B. that PID limits are hierarchical, so the most stringent
limit in the hierarchy is followed).”h]”hŒÇTo set a cgroup to have no limit, set pids.max to â€œmaxâ€. This is the default for
all new cgroups (N.B. that PID limits are hierarchical, so the most stringent
limit in the hierarchy is followed).”…””}”(hj/  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KhhîhžhubhÉ)”}”(hŒtpids.current tracks all child cgroup hierarchies, so parent/pids.current is a
superset of parent/child/pids.current.”h]”hŒtpids.current tracks all child cgroup hierarchies, so parent/pids.current is a
superset of parent/child/pids.current.”…””}”(hj=  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K"hhîhžhubhÉ)”}”(hŒ-The pids.events file contains event counters:”h]”hŒ-The pids.events file contains event counters:”…””}”(hjK  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K%hhîhžhubhŒblock_quote”“”)”}”(hŒ_- max: Number of times fork failed in the cgroup because limit was hit in
  self or ancestors.
”h]”hŒbullet_list”“”)”}”(hhh]”hŒ	list_item”“”)”}”(hŒ[max: Number of times fork failed in the cgroup because limit was hit in
self or ancestors.
”h]”hÉ)”}”(hŒZmax: Number of times fork failed in the cgroup because limit was hit in
self or ancestors.”h]”hŒZmax: Number of times fork failed in the cgroup because limit was hit in
self or ancestors.”…””}”(hjj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K'hjf  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jd  hja  ubah}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1j_  hŸh¶h K'hj[  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jY  hŸh¶h K'hhîhžhubeh}”(h]”Œusage”ah ]”h"]”Œusage”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒExample”h]”hŒExample”…””}”(hj—  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj”  hžhhŸh¶h K+ubhÉ)”}”(hŒ%First, we mount the pids controller::”h]”hŒ$First, we mount the pids controller:”…””}”(hj¥  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K-hj”  hžhubhŒliteral_block”“”)”}”(hŒQ# mkdir -p /sys/fs/cgroup/pids
# mount -t cgroup -o pids none /sys/fs/cgroup/pids”h]”hŒQ# mkdir -p /sys/fs/cgroup/pids
# mount -t cgroup -o pids none /sys/fs/cgroup/pids”…””}”hjµ  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1j³  hŸh¶h K/hj”  hžhubhÉ)”}”(hŒCThen we create a hierarchy, set limits and attach processes to it::”h]”hŒBThen we create a hierarchy, set limits and attach processes to it:”…””}”(hjÅ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K2hj”  hžhubj´  )”}”(hŒÀ# mkdir -p /sys/fs/cgroup/pids/parent/child
# echo 2 > /sys/fs/cgroup/pids/parent/pids.max
# echo $$ > /sys/fs/cgroup/pids/parent/cgroup.procs
# cat /sys/fs/cgroup/pids/parent/pids.current
2
#”h]”hŒÀ# mkdir -p /sys/fs/cgroup/pids/parent/child
# echo 2 > /sys/fs/cgroup/pids/parent/pids.max
# echo $$ > /sys/fs/cgroup/pids/parent/cgroup.procs
# cat /sys/fs/cgroup/pids/parent/pids.current
2
#”…””}”hjÓ  sbah}”(h]”h ]”h"]”h$]”h&]”jÃ  jÄ  uh1j³  hŸh¶h K4hj”  hžhubhÉ)”}”(hŒWIt should be noted that attempts to overcome the set limit (2 in this case) will
fail::”h]”hŒVIt should be noted that attempts to overcome the set limit (2 in this case) will
fail:”…””}”(hjá  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K;hj”  hžhubj´  )”}”(hŒ‘# cat /sys/fs/cgroup/pids/parent/pids.current
2
# ( /bin/echo "Here's some processes for you." | cat )
sh: fork: Resource temporary unavailable
#”h]”hŒ‘# cat /sys/fs/cgroup/pids/parent/pids.current
2
# ( /bin/echo "Here's some processes for you." | cat )
sh: fork: Resource temporary unavailable
#”…””}”hjï  sbah}”(h]”h ]”h"]”h$]”h&]”jÃ  jÄ  uh1j³  hŸh¶h K>hj”  hžhubhÉ)”}”(hŒ«Even if we migrate to a child cgroup (which doesn't have a set limit), we will
not be able to overcome the most stringent limit in the hierarchy (in this case,
parent's)::”h]”hŒ®Even if we migrate to a child cgroup (which doesnâ€™t have a set limit), we will
not be able to overcome the most stringent limit in the hierarchy (in this case,
parentâ€™s):”…””}”(hjý  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KDhj”  hžhubj´  )”}”(hX5  # echo $$ > /sys/fs/cgroup/pids/parent/child/cgroup.procs
# cat /sys/fs/cgroup/pids/parent/pids.current
2
# cat /sys/fs/cgroup/pids/parent/child/pids.current
2
# cat /sys/fs/cgroup/pids/parent/child/pids.max
max
# ( /bin/echo "Here's some processes for you." | cat )
sh: fork: Resource temporary unavailable
#”h]”hX5  # echo $$ > /sys/fs/cgroup/pids/parent/child/cgroup.procs
# cat /sys/fs/cgroup/pids/parent/pids.current
2
# cat /sys/fs/cgroup/pids/parent/child/pids.current
2
# cat /sys/fs/cgroup/pids/parent/child/pids.max
max
# ( /bin/echo "Here's some processes for you." | cat )
sh: fork: Resource temporary unavailable
#”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jÃ  jÄ  uh1j³  hŸh¶h KHhj”  hžhubhÉ)”}”(hŒ«We can set a limit that is smaller than pids.current, which will stop any new
processes from being forked at all (note that the shell itself counts towards
pids.current)::”h]”hŒªWe can set a limit that is smaller than pids.current, which will stop any new
processes from being forked at all (note that the shell itself counts towards
pids.current):”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KShj”  hžhubj´  )”}”(hX!  # echo 1 > /sys/fs/cgroup/pids/parent/pids.max
# /bin/echo "We can't even spawn a single process now."
sh: fork: Resource temporary unavailable
# echo 0 > /sys/fs/cgroup/pids/parent/pids.max
# /bin/echo "We can't even spawn a single process now."
sh: fork: Resource temporary unavailable
#”h]”hX!  # echo 1 > /sys/fs/cgroup/pids/parent/pids.max
# /bin/echo "We can't even spawn a single process now."
sh: fork: Resource temporary unavailable
# echo 0 > /sys/fs/cgroup/pids/parent/pids.max
# /bin/echo "We can't even spawn a single process now."
sh: fork: Resource temporary unavailable
#”…””}”hj'  sbah}”(h]”h ]”h"]”h$]”h&]”jÃ  jÄ  uh1j³  hŸh¶h KWhj”  hžhubeh}”(h]”Œexample”ah ]”h"]”Œexample”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K+ubeh}”(h]”Œprocess-number-controller”ah ]”h"]”Œprocess number controller”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	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”jh  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”h¶Œ_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”}”(jB  j?  hëhèj‘  jŽ  j:  j7  uŒ	nametypes”}”(jB  ‰hë‰j‘  ‰j:  ‰uh}”(j?  h£hèh·jŽ  hîj7  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
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nhžhub.