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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2017-12-25 17:34:20 +0100 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2017-12-27 06:32:48 +0100 |
| commit | 2468f14e4b4cfb74f7661ef7f488ef5f0e51f61d (patch) | |
| tree | 2cdc1c1ccd452f1e286a5eb142017dcb2319268e /man7/cgroups.7 | |
| parent | 4f017a682cdd7aca62e23335400306f6df04f420 (diff) | |
| download | man-pages-2468f14e4b4cfb74f7661ef7f488ef5f0e51f61d.tar.gz | |
cgroups.7: Relocate the 'Cgroups v2 "no internal processes" rule' subsection
Logically, this section should follow the section that
describes cgroup.subtree_control.
No content changes in this patch.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Diffstat (limited to 'man7/cgroups.7')
| -rw-r--r-- | man7/cgroups.7 | 90 |
1 files changed, 45 insertions, 45 deletions
diff --git a/man7/cgroups.7 b/man7/cgroups.7 index 5aedab43f6..9d402d1c74 100644 --- a/man7/cgroups.7 +++ b/man7/cgroups.7 @@ -619,51 +619,6 @@ and .I cpuacct controllers. .\" -.SS Cgroups v2 """no internal processes""" rule -Cgroups v2 enforces a so-called "no internal processes" rule. -Roughly speaking, this rule means that, -with the exception of the root cgroup, processes may reside -only in leaf nodes (cgroups that do not themselves contain child cgroups). -This avoids the need to decide how to partition resources between -processes which are members of cgroup A and processes in child cgroups of A. -.PP -For instance, if cgroup -.I /cg1/cg2 -exists, then a process may reside in -.IR /cg1/cg2 , -but not in -.IR /cg1 . -This is to avoid an ambiguity in cgroups v1 -with respect to the delegation of resources between processes in -.I /cg1 -and its child cgroups. -The recommended approach in cgroups v2 is to create a subdirectory called -.I leaf -for any nonleaf cgroup which should contain processes, but no child cgroups. -Thus, processes which previously would have gone into -.I /cg1 -would now go into -.IR /cg1/leaf . -This has the advantage of making explicit -the relationship between processes in -.I /cg1/leaf -and -.IR /cg1 's -other children. -.PP -The "no internal processes" rule is in fact more subtle than stated above. -More precisely, the rule is that a (nonroot) cgroup can't both -(1) have member processes, and -(2) distribute resources into child cgroups\(emthat is, have a nonempty -.I cgroup.subtree_control -file. -Thus, it -.I is -possible for a cgroup to have both member processes and child cgroups, -but before controllers can be enabled for that cgroup, -the member processes must be moved out of the cgroup -(e.g., perhaps into the child cgroups). -.\" .SS Cgroups v2 subtree control Each cgroup in the v2 hierarchy contains the following two files: .TP @@ -725,6 +680,51 @@ then the corresponding controller-interface files (e.g., are automatically created in the children of that cgroup and can be used to exert resource control in the child cgroups. .\" +.SS Cgroups v2 """no internal processes""" rule +Cgroups v2 enforces a so-called "no internal processes" rule. +Roughly speaking, this rule means that, +with the exception of the root cgroup, processes may reside +only in leaf nodes (cgroups that do not themselves contain child cgroups). +This avoids the need to decide how to partition resources between +processes which are members of cgroup A and processes in child cgroups of A. +.PP +For instance, if cgroup +.I /cg1/cg2 +exists, then a process may reside in +.IR /cg1/cg2 , +but not in +.IR /cg1 . +This is to avoid an ambiguity in cgroups v1 +with respect to the delegation of resources between processes in +.I /cg1 +and its child cgroups. +The recommended approach in cgroups v2 is to create a subdirectory called +.I leaf +for any nonleaf cgroup which should contain processes, but no child cgroups. +Thus, processes which previously would have gone into +.I /cg1 +would now go into +.IR /cg1/leaf . +This has the advantage of making explicit +the relationship between processes in +.I /cg1/leaf +and +.IR /cg1 's +other children. +.PP +The "no internal processes" rule is in fact more subtle than stated above. +More precisely, the rule is that a (nonroot) cgroup can't both +(1) have member processes, and +(2) distribute resources into child cgroups\(emthat is, have a nonempty +.I cgroup.subtree_control +file. +Thus, it +.I is +possible for a cgroup to have both member processes and child cgroups, +but before controllers can be enabled for that cgroup, +the member processes must be moved out of the cgroup +(e.g., perhaps into the child cgroups). +.\" .SS Cgroups v2 cgroup.events file With cgroups v2, a new mechanism is provided to obtain notification about when a cgroup becomes empty. |