diff options
Diffstat (limited to 'Documentation/sysctl/fs.txt')
| -rw-r--r-- | Documentation/sysctl/fs.txt | 74 |
1 files changed, 72 insertions, 2 deletions
diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt index f99254327ae5..1458448436cc 100644 --- a/Documentation/sysctl/fs.txt +++ b/Documentation/sysctl/fs.txt @@ -1,5 +1,6 @@ Documentation for /proc/sys/fs/* kernel version 2.2.10 (c) 1998, 1999, Rik van Riel <riel@nl.linux.org> + (c) 2009, Shen Feng<shen@cn.fujitsu.com> For general info and legal blurb, please look in README. @@ -14,7 +15,12 @@ kernel. Since some of the files _can_ be used to screw up your system, it is advisable to read both documentation and source before actually making adjustments. +1. /proc/sys/fs +---------------------------------------------------------- + Currently, these files are in /proc/sys/fs: +- aio-max-nr +- aio-nr - dentry-state - dquot-max - dquot-nr @@ -30,8 +36,15 @@ Currently, these files are in /proc/sys/fs: - super-max - super-nr -Documentation for the files in /proc/sys/fs/binfmt_misc is -in Documentation/binfmt_misc.txt. +============================================================== + +aio-nr & aio-max-nr: + +aio-nr is the running total of the number of events specified on the +io_setup system call for all currently active aio contexts. If aio-nr +reaches aio-max-nr then io_setup will fail with EAGAIN. Note that +raising aio-max-nr does not result in the pre-allocation or re-sizing +of any kernel data structures. ============================================================== @@ -178,3 +191,60 @@ requests. aio-max-nr allows you to change the maximum value aio-nr can grow to. ============================================================== + + +2. /proc/sys/fs/binfmt_misc +---------------------------------------------------------- + +Documentation for the files in /proc/sys/fs/binfmt_misc is +in Documentation/binfmt_misc.txt. + + +3. /proc/sys/fs/mqueue - POSIX message queues filesystem +---------------------------------------------------------- + +The "mqueue" filesystem provides the necessary kernel features to enable the +creation of a user space library that implements the POSIX message queues +API (as noted by the MSG tag in the POSIX 1003.1-2001 version of the System +Interfaces specification.) + +The "mqueue" filesystem contains values for determining/setting the amount of +resources used by the file system. + +/proc/sys/fs/mqueue/queues_max is a read/write file for setting/getting the +maximum number of message queues allowed on the system. + +/proc/sys/fs/mqueue/msg_max is a read/write file for setting/getting the +maximum number of messages in a queue value. In fact it is the limiting value +for another (user) limit which is set in mq_open invocation. This attribute of +a queue must be less or equal then msg_max. + +/proc/sys/fs/mqueue/msgsize_max is a read/write file for setting/getting the +maximum message size value (it is every message queue's attribute set during +its creation). + + +4. /proc/sys/fs/epoll - Configuration options for the epoll interface +-------------------------------------------------------- + +This directory contains configuration options for the epoll(7) interface. + +max_user_instances +------------------ + +This is the maximum number of epoll file descriptors that a single user can +have open at a given time. The default value is 128, and should be enough +for normal users. + +max_user_watches +---------------- + +Every epoll file descriptor can store a number of files to be monitored +for event readiness. Each one of these monitored files constitutes a "watch". +This configuration option sets the maximum number of "watches" that are +allowed for each user. +Each "watch" costs roughly 90 bytes on a 32bit kernel, and roughly 160 bytes +on a 64bit one. +The current default value for max_user_watches is the 1/32 of the available +low memory, divided for the "watch" cost in bytes. + |