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| author | Stanislav Kinsbursky <skinsbursky@parallels.com> | 2013-01-04 15:34:50 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-01-04 16:11:45 -0800 |
| commit | 03f595668017f1a1fb971c02fc37140bc6e7bb1c (patch) | |
| tree | 3aa5c4b32b5fd396f0d74679548de8c09ca195a1 /Documentation | |
| parent | 9afdacda0252fc1ddb7907728e878518edbcdfce (diff) | |
| download | linux-03f595668017f1a1fb971c02fc37140bc6e7bb1c.tar.gz linux-03f595668017f1a1fb971c02fc37140bc6e7bb1c.tar.bz2 linux-03f595668017f1a1fb971c02fc37140bc6e7bb1c.zip | |
ipc: add sysctl to specify desired next object id
Add 3 new variables and sysctls to tune them (by one "next_id" variable
for messages, semaphores and shared memory respectively). This variable
can be used to set desired id for next allocated IPC object. By default
it's equal to -1 and old behaviour is preserved. If this variable is
non-negative, then desired idr will be extracted from it and used as a
start value to search for free IDR slot.
Notes:
1) this patch doesn't guarantee that the new object will have desired
id. So it's up to user space how to handle new object with wrong id.
2) After a sucessful id allocation attempt, "next_id" will be set back
to -1 (if it was non-negative).
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 2907ba6c3607..51b953a1b149 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -38,6 +38,7 @@ show up in /proc/sys/kernel: - l2cr [ PPC only ] - modprobe ==> Documentation/debugging-modules.txt - modules_disabled +- msg_next_id [ sysv ipc ] - msgmax - msgmnb - msgmni @@ -62,7 +63,9 @@ show up in /proc/sys/kernel: - rtsig-max - rtsig-nr - sem +- sem_next_id [ sysv ipc ] - sg-big-buff [ generic SCSI device (sg) ] +- shm_next_id [ sysv ipc ] - shm_rmid_forced - shmall - shmmax [ sysv ipc ] @@ -320,6 +323,22 @@ to false. ============================================================== +msg_next_id, sem_next_id, and shm_next_id: + +These three toggles allows to specify desired id for next allocated IPC +object: message, semaphore or shared memory respectively. + +By default they are equal to -1, which means generic allocation logic. +Possible values to set are in range {0..INT_MAX}. + +Notes: +1) kernel doesn't guarantee, that new object will have desired id. So, +it's up to userspace, how to handle an object with "wrong" id. +2) Toggle with non-default value will be set back to -1 by kernel after +successful IPC object allocation. + +============================================================== + nmi_watchdog: Enables/Disables the NMI watchdog on x86 systems. When the value is |