From 1052e1fbccf4e30a373db3862487e154e3986b62 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Fri, 26 Sep 2014 15:25:07 +0200 Subject: [PATCH] mq_overview.7: Update queues_max details for Linux 3.14 And in general rework the text a little. Signed-off-by: Michael Kerrisk --- man7/mq_overview.7 | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/man7/mq_overview.7 b/man7/mq_overview.7 index 0e025e6f0..06023ebb8 100644 --- a/man7/mq_overview.7 +++ b/man7/mq_overview.7 @@ -265,18 +265,36 @@ number of message queues that can be created. The default value for .I queues_max is 256. +The semantics of this limit have changed across kernel versions as follows: +.RS +.IP * 3 Before Linux 3.5, this limit could be changed to any value in the range 0 to -.RB INT_MAX ; -since Linux 3.5, the ceiling for this limit is 1024 +.RB INT_MAX , +but privileged processes +.RB ( CAP_SYS_RESOURCE ) +can exceed the limit. +.IP * 3 +Since Linux 3.5, there is a ceiling for this limit of 1024 .RB ( HARD_QUEUESMAX ). Privileged processes .RB ( CAP_SYS_RESOURCE ) can exceed the .I queues_max -limit, but since Linux 3.5, the +limit, but the .BR HARD_QUEUESMAX limit is enforced even for privileged processes. +.IP * +Starting with Linux 3.14, +.\" commit f3713fd9cff733d9df83116422d8e4af6e86b2bb +the +.B HARD_QUEUESMAX +ceiling is removed: no ceiling is imposed on the +.IR queues_max +limit, and privileged processes +.RB ( CAP_SYS_RESOURCE ) +can exceed the limit. +.RE .SS Resource limit The .B RLIMIT_MSGQUEUE