> Yet I had to resubmit the patch and the explanation at least
> *THREE* times, over the course of 2-3 weeks, before I finally got a
> response out of you. And this was for a utterly uncontroversial patch!
It get's even worse -- I've submitted a *DOCUMENTATION*
update four times now, and it hasn't been included!
Gosh, it doesn't even touch a _single_ line of code,
only the files in Documentation/sysctl/...
Guess I'll just resubmit it again ;(
Here it is, especially included for all you real users
and sysadmin dudes...
Rik.
+-------------------------------------------------------------------+
| Linux memory management tour guide. H.H.vanRiel@phys.uu.nl |
| Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ |
+-------------------------------------------------------------------+
diff -dNur linux-2.1.123/Documentation/sysctl/README linux/Documentation/sysctl/README
--- linux-2.1.123/Documentation/sysctl/README Fri Sep 25 16:35:38 1998
+++ linux/Documentation/sysctl/README Wed Sep 30 00:38:05 1998
@@ -1,4 +1,4 @@
-Documentation for /proc/sys/*/* version 0.1
+Documentation for /proc/sys/ kernel version 2.1.122
(c) 1998, Rik van Riel <H.H.vanRiel@phys.uu.nl>
'Why', I hear you ask, 'would anyone even _want_ documentation
@@ -12,6 +12,9 @@
Furthermore, the programmers who built sysctl have built it to
be actually used, not just for the fun of programming it :-)
+If you prefer HTML, feel free to visit the Linux-MM homepage
+<http://www.phys.uu.nl/~riel/mm-patch/>...
+
==============================================================
Legal blurb:
@@ -58,9 +61,9 @@
debug/ <empty>
dev/ device specific information (eg dev/cdrom/info)
fs/ specific filesystems
+ filehandle, inode, dentry and quota tuning
binfmt_misc <linux/Documentation/binfmt_misc.txt>
kernel/ global kernel info / tuning
- open file / inode tuning
miscellaneous stuff
net/ networking stuff, for documentation look in:
<linux/Documentation/networking/>
diff -dNur linux-2.1.123/Documentation/sysctl/fs.txt linux/Documentation/sysctl/fs.txt
--- linux-2.1.123/Documentation/sysctl/fs.txt Thu Jan 1 01:00:00 1970
+++ linux/Documentation/sysctl/fs.txt Wed Sep 30 00:38:10 1998
@@ -0,0 +1,116 @@
+Documentation for /proc/sys/fs/* kernel version 2.1.122
+ (c) 1998, Rik van Riel <H.H.vanRiel@phys.uu.nl>
+
+For general info and legal blurb, please look in README.
+
+==============================================================
+
+This file contains documentation for the sysctl files in
+/proc/sys/fs/ and is valid for Linux kernel version 2.1.
+
+The files in this directory can be used to tune and monitor
+miscellaneous and general things in the operation of the Linux
+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.
+
+Currently, these files are in /proc/sys/fs:
+- dentry-state
+- dquot-max
+- dquot-nr
+- file-max
+- file-nr
+- inode-max
+- inode-nr
+- inode-state
+
+Documentation for the files in /proc/sys/fs/binfmt_misc is
+in Documentation/binfmt_misc.txt.
+
+==============================================================
+
+dentry-state:
+
+From linux/fs/dentry.c:
+--------------------------------------------------------------
+struct {
+ int nr_dentry;
+ int nr_unused;
+ int age_limit; /* age in seconds */
+ int want_pages; /* pages requested by system */
+ int dummy[2];
+} dentry_stat = {0, 0, 45, 0,};
+--------------------------------------------------------------
+
+Dentries are dynamically allocated and deallocated, and
+nr_dentry seems to be 0 all the time. Hence it's safe to
+assume that only nr_unused, age_limit and want_pages are
+used. Nr_unused seems to be exactly what its name says.
+Age_limit is the age in seconds after which dcache entries
+can be reclaimed when memory is short and want_pages is
+nonzero when shrink_dcache_pages() has been called and the
+dcache isn't pruned yet.
+
+==============================================================
+
+dquot-max & dquot-nr:
+
+The file dquot-max shows the maximum number of cached disk
+quota entries.
+
+The file dquot-nr shows the number of allocated disk quota
+entries and the number of free disk quota entries.
+
+If the number of free cached disk quotas is very low and
+you have some awesome number of simultaneous system users,
+you might want to raise the limit.
+
+==============================================================
+
+file-max & file-nr:
+
+The kernel allocates file handles dynamically, but as yet it
+doesn't free them again.
+
+The value in file-max denotes the maximum number of file-
+handles that the Linux kernel will allocate. When you get lots
+of error messages about running out of file handles, you might
+want to increase this limit.
+
+The three values in file-nr denote the number of allocated
+file handles, the number of used file handles and the maximum
+number of file handles. When the allocated file handles come
+close to the maximum, but the number of actually used ones is
+far behind, you've encountered a peak in your usage of file
+handles and you don't need to increase the maximum.
+
+==============================================================
+
+inode-max, inode-nr & inode-state:
+
+As with file handles, the kernel allocates the inode structures
+dynamically, but can't free them yet.
+
+The value in inode-max denotes the maximum number of inode
+handlers. This value should be 3-4 times larger than the value
+in file-max, since stdin, stdout and network sockets also
+need an inode struct to handle them. When you regularly run
+out of inodes, you need to increase this value.
+
+The file inode-nr contains the first two items from
+inode-state, so we'll skip to that file...
+
+Inode-state contains three actual numbers and four dummies.
+The actual numbers are, in order of appearance, nr_inodes,
+nr_free_inodes and preshrink.
+
+Nr_inodes stands for the number of inodes the system has
+allocated, this can be slightly more than inode-max because
+Linux allocates them one pageful at a time.
+
+Nr_free_inodes represents the number of free inodes (?) and
+preshrink is nonzero when the nr_inodes > inode-max and the
+system needs to prune the inode list instead of allocating
+more.
+
+
diff -dNur linux-2.1.123/Documentation/sysctl/kernel.txt linux/Documentation/sysctl/kernel.txt
--- linux-2.1.123/Documentation/sysctl/kernel.txt Fri Sep 25 16:35:38 1998
+++ linux/Documentation/sysctl/kernel.txt Wed Sep 30 00:38:10 1998
@@ -1,4 +1,4 @@
-Documentation for /proc/sys/kernel/* version 0.1
+Documentation for /proc/sys/kernel/* kernel version 2.1.122
(c) 1998, Rik van Riel <H.H.vanRiel@phys.uu.nl>
For general info and legal blurb, please look in README.
@@ -14,25 +14,25 @@
system, it is advisable to read both documentation and source
before actually making adjustments.
-Currently, these files are in /proc/sys/kernel:
+These files might (depending on your configuration) show
+up in /proc/sys/kernel:
- ctrl-alt-del
-- dentry-state
- domainname
-- file-max
-- file-nr
- hostname
-- inode-max
-- inode-nr
-- inode-state
+- htab-reclaim [ PPC only ]
+- java-appletviewer [ binfmt_java, obsolete ]
+- java-interpreter [ binfmt_java, obsolete ]
- modprobe ==> Documentation/kmod.txt
- osrelease
- ostype
- panic
+- powersave-nap [ PPC only ]
- printk
-- real-root-dev ==> Documentation/initrd.txt
-- reboot-cmd ==> SPARC specific
-- securelevel
+- real-root-dev ==> Documentation/initrd.txt
+- reboot-cmd [ SPARC only ]
+- sg-big-buff [ Generic SCSI interface (sg) ]
- version
+- zero-paged [ PPC only ]
==============================================================
@@ -51,30 +51,6 @@
==============================================================
-dentry-state:
-
-From linux/fs/dentry.c:
---------------------------------------------------------------
-struct {
- int nr_dentry;
- int nr_unused;
- int age_limit; /* age in seconds */
- int want_pages; /* pages requested by system */
- int dummy[2];
-} dentry_stat = {0, 0, 45, 0,};
---------------------------------------------------------------
-
-Dentries are dynamically allocated and deallocated, and
-nr_dentry seems to be 0 all the time. Hence it's safe to
-assume that only nr_unused, age_limit and want_pages are
-used. Nr_unused seems to be exactly what its name says.
-Age_limit is the age in seconds after which dcache entries
-can be reclaimed when memory is short and want_pages is
-nonzero when shrink_dcache_pages() has been called and the
-dcache isn't pruned yet.
-
-==============================================================
-
domainname & hostname:
These files can be controlled to set the domainname and
@@ -86,52 +62,12 @@
==============================================================
-file-max & file-nr:
-
-The kernel allocates file handles dynamically, but as yet it
-doesn't free them again.
-
-The value in file-max denotes the maximum number of file-
-handles that the Linux kernel will allocate. When you get lots
-of error messages about running out of file handles, you might
-want to increase this limit.
-
-The three values in file-nr denote the number of allocated
-file handles, the number of used file handles and the maximum
-number of file handles. When the allocated file handles come
-close to the maximum, but the number of actually used ones is
-far behind, you've encountered a peak in your usage of file
-handles and you don't need to increase the maximum.
-
-==============================================================
-
-inode-max, inode-nr & inode-state:
-
-As with file handles, the kernel allocates the inode structures
-dynamically, but can't free them yet.
-
-The value in inode-max denotes the maximum number of inode
-handlers. This value should be 3-4 times larger than the value
-in file-max, since stdin, stdout and network sockets also
-need an inode struct to handle them. When you regularly run
-out of inodes, you need to increase this value.
-
-The file inode-nr contains the first two items from
-inode-state, so we'll skip to that file...
-
-Inode-state contains three actual numbers and four dummies.
-The actual numbers are, in order of appearance, nr_inodes,
-nr_free_inodes and preshrink.
-
-Nr_inodes stands for the number of inodes the system has
-allocated, this can be slightly more than inode-max because
-Linux allocates them one pageful at a time.
-
-Nr_free_inodes represents the number of free inodes (?) and
-preshrink is nonzero when the nr_inodes > inode-max and the
-system needs to prune the inode list instead of allocating
-more.
+htab-reclaim: (PPC only)
+Setting this to a non-zero value, the PowerPC htab
+(see Documentation/powerpc/ppc_htab.txt) is pruned
+each time the system hits the idle loop.
+
==============================================================
osrelease, ostype & version:
@@ -159,6 +95,13 @@
==============================================================
+powersave-nap: (PPC only)
+
+If set, Linux-PPC will use the 'nap' mode of powersaving,
+otherwise the 'doze' mode will be used.
+
+==============================================================
+
printk:
The four values in printk denote: console_loglevel,
@@ -184,27 +127,30 @@
==============================================================
-securelevel:
+reboot-cmd: (Sparc only)
-When the value in this file is nonzero, root is prohibited
-from:
-- changing the immutable and append-only flags on files
-- changing sysctl things (limited ???)
+??? This seems to be a way to give an argument to the Sparc
+ROM/Flash boot loader. Maybe to tell it what to do after
+rebooting. ???
==============================================================
-real-root-dev: (CONFIG_INITRD only)
+sg-big-buff:
-This file is used to configure the real root device when using
-an initial ramdisk to configure the system before switching to
-the 'real' root device. See linux/Documentation/initrd.txt for
-more info.
+This file shows the size of the generic SCSI (sg) buffer.
+You can't tune it just yet, but you could change it on
+compile time by editing include/scsi/sg.h and changing
+the value of SG_BIG_BUFF.
-==============================================================
+There shouldn't be any reason to change this value. If
+you can come up with one, you probably know what you
+are doing anyway :)
-reboot-cmd: (Sparc only)
+==============================================================
-??? This seems to be a way to give an argument to the Sparc
-ROM/Flash boot loader. Maybe to tell it what to do after
-rebooting. ???
+zero-paged: (PPC only)
+When enabled (non-zero), Linux-PPC will pre-zero pages in
+the idle loop, possibly speeding up get_free_pages. Since
+this only affects what the idle loop is doing, you should
+enable this and see if anything changes.
diff -dNur linux-2.1.123/Documentation/sysctl/vm.txt linux/Documentation/sysctl/vm.txt
--- linux-2.1.123/Documentation/sysctl/vm.txt Fri Sep 25 16:35:38 1998
+++ linux/Documentation/sysctl/vm.txt Wed Sep 30 00:38:10 1998
@@ -1,4 +1,4 @@
-Documentation for /proc/sys/vm/* version 0.1
+Documentation for /proc/sys/vm/* kernel version 2.1.122
(c) 1998, Rik van Riel <H.H.vanRiel@phys.uu.nl>
For general info and legal blurb, please look in README.
@@ -20,6 +20,7 @@
- kswapd
- overcommit_memory
- pagecache
+- pagetable_cache
- swapctl
- swapout_interval
@@ -56,7 +57,7 @@
} bdf_prm = {{40, 500, 64, 256, 15, 30*HZ, 5*HZ, 1884, 2}};
--------------------------------------------------------------
-The first parameter governs the maximum number of of dirty
+The first parameter governs the maximum number of dirty
buffers in the buffer cache. Dirty means that the contents
of the buffer still have to be written to disk (as opposed
to a clean buffer, which can just be forgotten about).
@@ -101,8 +102,9 @@
min_percent -- this is the minimum percentage of memory
that should be spent on buffer memory
borrow_percent -- when Linux is short on memory, and the
- buffer cache uses more memory, free pages
- are stolen from it
+ buffer cache uses more memory than this,
+ the MM subsystem will prune the buffercache
+ more heavily than other memory
max_percent -- this is the maximum amount of memory that
can be used for buffer memory
@@ -112,25 +114,17 @@
This file contains the values in the struct freepages. That
struct contains three members: min, low and high.
-Although the goal of the Linux memory management subsystem
-is to avoid fragmentation and make large chunks of free
-memory (so that we can hand out DMA buffers and such), there
-still are some page-based limits in the system, mainly to
-make sure we don't waste too much memory trying to get large
-free area's.
-
The meaning of the numbers is:
freepages.min When the number of free pages in the system
reaches this number, only the kernel can
allocate more memory.
-freepages.low If memory is too fragmented, the swapout
- daemon is started, except when the number
- of free pages is larger than freepages.low.
-freepages.high The swapping daemon exits when memory is
- sufficiently defragmented, when the number
- of free pages reaches freepages.high or when
- it has tried the maximum number of times.
+freepages.low If the number of free pages gets below this
+ point, the kernel starts swapping agressively.
+freepages.high The kernel tries to keep up to this amount of
+ memory free; if memory comes below this point,
+ the kernel gently starts swapping in the hopes
+ that it never has to do real agressive swapping.
==============================================================
@@ -210,11 +204,29 @@
This file does exactly the same as buffermem, only this
file controls the struct page_cache, and thus controls
-the amount of memory allowed for memory mapping of files.
+the amount of memory allowed for memory mapping and generic
+caching of files.
You don't want the minimum level to be too low, otherwise
your system might thrash when memory is tight or fragmentation
is high...
+
+==============================================================
+
+pagetable_cache:
+
+The kernel keeps a number of page tables in a per-processor
+cache (this helps a lot on SMP systems). The cache size for
+each processor will be between the low and the high value.
+
+On a low-memory, single CPU system you can safely set these
+values to 0 so you don't waste the memory. On SMP systems it
+is used so that the system can do fast pagetable allocations
+without having to aquire the kernel memory lock.
+
+For large systems, the settings are probably OK. For normal
+systems they won't hurt a bit. For small systems (<16MB ram)
+it might be advantageous to set both values to 0.
==============================================================
-
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