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| -rw-r--r-- | man5/proc.5 | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/man5/proc.5 b/man5/proc.5 index e5632dcce3..520c5fc8e2 100644 --- a/man5/proc.5 +++ b/man5/proc.5 @@ -2965,6 +2965,42 @@ the value of .BR SG_BIG_BUFF . However, there shouldn't be any reason to change this value. .TP +.IR /proc/sys/kernel/shm_rmid_forced " (since Linux 3.1)" +.\" commit b34a6b1da371ed8af1221459a18c67970f7e3d53 +.\" See also Documentation/sysctl/kernel.txt +If this file is set to 1, all System V shared memory segments will +be marked for destruction as soon as the number of attached processes +falls to zero; +in other words, it is no longer possible to create shared memory segments +that exist independently of any attached process. +.IP +The effect is as though a +.BR shmctl (2) +.B IPC_RMID +is performed on all existing segments as well as all segments +created in the future (until this file is reset to 0). +Note that existing segments that are attached to no process will be +immediately destroyed when this file is set to 1. +Setting this option will also destroy segments that were created, +but never attached, +upon termination of the process that created the segment with +.BR shmget (2). +.IP +Setting this file to 1 provides a way of ensuring that +all System V shared memory segments are counted against the +resource usage and resource limits (see the description of +.B RLIMIT_AS +in +.BR getrlimit (2)) +of at least one process. +.IP +Because setting this file to 1 produces behavior that is nonstandard +and could also break existing applications, +the default value in this file is 0. +Only set this file to 1 if you have a good understanding +of the semantics of the applications using +System V shared memory on your system. +.TP .I /proc/sys/kernel/shmall This file contains the system-wide limit on the total number of pages of |