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authorDavid Woodhouse <David.Woodhouse@intel.com>2009-01-05 10:50:33 +0100
committerDavid Woodhouse <David.Woodhouse@intel.com>2009-01-05 10:50:33 +0100
commit353816f43d1fb340ff2d9a911dd5d0799c09f6a5 (patch)
tree517290fd884d286fe2971137ac89f89e3567785a /Documentation/scheduler
parent160bbab3000dafccbe43688e48208cecf4deb879 (diff)
parentfe0bdec68b77020281dc814805edfe594ae89e0f (diff)
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts: arch/arm/mach-pxa/corgi.c arch/arm/mach-pxa/poodle.c arch/arm/mach-pxa/spitz.c
Diffstat (limited to 'Documentation/scheduler')
-rw-r--r--Documentation/scheduler/sched-arch.txt4
-rw-r--r--Documentation/scheduler/sched-design-CFS.txt21
2 files changed, 23 insertions, 2 deletions
diff --git a/Documentation/scheduler/sched-arch.txt b/Documentation/scheduler/sched-arch.txt
index 941615a9769..d43dbcbd163 100644
--- a/Documentation/scheduler/sched-arch.txt
+++ b/Documentation/scheduler/sched-arch.txt
@@ -8,7 +8,7 @@ Context switch
By default, the switch_to arch function is called with the runqueue
locked. This is usually not a problem unless switch_to may need to
take the runqueue lock. This is usually due to a wake up operation in
-the context switch. See include/asm-ia64/system.h for an example.
+the context switch. See arch/ia64/include/asm/system.h for an example.
To request the scheduler call switch_to with the runqueue unlocked,
you must `#define __ARCH_WANT_UNLOCKED_CTXSW` in a header file
@@ -23,7 +23,7 @@ disabled. Interrupts may be enabled over the call if it is likely to
introduce a significant interrupt latency by adding the line
`#define __ARCH_WANT_INTERRUPTS_ON_CTXSW` in the same place as for
unlocked context switches. This define also implies
-`__ARCH_WANT_UNLOCKED_CTXSW`. See include/asm-arm/system.h for an
+`__ARCH_WANT_UNLOCKED_CTXSW`. See arch/arm/include/asm/system.h for an
example.
diff --git a/Documentation/scheduler/sched-design-CFS.txt b/Documentation/scheduler/sched-design-CFS.txt
index eb471c7a905..8398ca4ff4e 100644
--- a/Documentation/scheduler/sched-design-CFS.txt
+++ b/Documentation/scheduler/sched-design-CFS.txt
@@ -273,3 +273,24 @@ task groups and modify their CPU share using the "cgroups" pseudo filesystem.
# #Launch gmplayer (or your favourite movie player)
# echo <movie_player_pid> > multimedia/tasks
+
+8. Implementation note: user namespaces
+
+User namespaces are intended to be hierarchical. But they are currently
+only partially implemented. Each of those has ramifications for CFS.
+
+First, since user namespaces are hierarchical, the /sys/kernel/uids
+presentation is inadequate. Eventually we will likely want to use sysfs
+tagging to provide private views of /sys/kernel/uids within each user
+namespace.
+
+Second, the hierarchical nature is intended to support completely
+unprivileged use of user namespaces. So if using user groups, then
+we want the users in a user namespace to be children of the user
+who created it.
+
+That is currently unimplemented. So instead, every user in a new
+user namespace will receive 1024 shares just like any user in the
+initial user namespace. Note that at the moment creation of a new
+user namespace requires each of CAP_SYS_ADMIN, CAP_SETUID, and
+CAP_SETGID.