Commit Graph

67 Commits

Author SHA1 Message Date
Mateusz Piotrowski
8bd4b3f949 Use Cm macros instead of Ar when referring to a specific memory disk type
MFC after:	3 days
2020-11-06 15:55:13 +00:00
Mateusz Piotrowski
f35062c735 Fix a typo and remove Xr's to vn(4) and vnconfig(4)
"mandoc -Tlint" complained about the Xr to vnconfig, which was removed in
r238202.  I am not sure but maybe it's time to do the same to vn(4).

MFC after:	2 weeks
2020-11-06 15:38:51 +00:00
Bruce Evans
9e5ed8593f Use VOP_ADVISE() with POSIX_FADV_DONTNEED instead of IO_DIRECT to
implement not double-caching for reads from vnode-backed md devices.
Use VOP_ADVISE() similarly instead of !IO_DIRECT unsimilarly for writes.
Add a "cache" option to mdconfig to allow changing the default of not
caching.

This depends on a recent commit to fix VOP_ADVISE().  A previous version
had optimizations for sequential i/o's (merge the i/o's and only uncache
for discontiguous i/o's and for full blocks), but optimizations and
knowledge of block boundaries belong in VOP_ADVISE().  Read-ahead should
also be handled better, by supporting it in md and discarding it in
VOP_ADVISE().

POSIX_FADV_DONTNEED is ignored by zfs, but so is IO_DIRECT.

POSIX_FADV_DONTNEED works better than IO_DIRECT if it is not ignored,
since it only discards from the buffer cache immediately, while
IO_DIRECT also discards from the page cache immediately.

IO_DIRECT was not used for writes since it was claimed to be too slow,
but most of the slowness for writes is from doing them synchronously by
default.  Non-synchronous writes still deadlock in many cases.

IO_DIRECT only has a special implementation for ffs reads with DIRECTIO
configured.  Otherwise, if it is not ignored than it uses the buffer and
page caches normally except for discarding everything after each i/o,
and then it has much the same overheads as POSIX_FADV_DONTNEED.  The
overheads for reading with ffs and DIRECTIO were similar in tests of md.

Reviewed by:	kib
2018-12-21 08:15:31 +00:00
Maxim Sobolev
f7ca2bbe44 Add ability to label md(4) devices.
This feature comes from the fact that we rely memory-backed md(4)
in our build process heavily. However, if the build goes haywire
the allocated resources (i.e. swap and memory-backed md(4)'s) need
to be purged. It is extremely useful to have ability to attach
arbitrary labels to each of the virtual disks so that they can
be identified and GC'ed if neecessary.

MFC after:	4 weeks
Differential Revision:	https://reviews.freebsd.org/D10457
2017-08-28 15:54:07 +00:00
Stephen J. Kiernan
9a81ba0f24 Add MD_VERIFY option to enable O_VERIFY in open for vnode type.
Add -o [no]verify option to mdconfig (and document in man page.)
Implement GEOM attribute MNT::verified to ask md if the backing vnode is
  verified.
Check for MNT::verified in cd9660 mount to flag the mount as MNT_VERIFIED if
  the underlying device has been verified.

Reviewed by:	rwatson
Approved by:	sjg (mentor)
Obtained from:	Juniper Networks, Inc.
Differential Revision:	https://reviews.freebsd.org/D2902
2017-05-31 21:18:11 +00:00
Edward Tomasz Napierala
d5b0fb47eb Add 'p' postfix to mdconfig(8).
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
2015-10-10 09:37:31 +00:00
Edward Tomasz Napierala
b8c19fd719 It's 2015, and some people are still trying to use fdisk and then
go asking what debug flags to set for GEOM to make it work.  Advice
them to use gpart(8) instead.

Something similar should probably done with disklabel,
but I need to rewrite the disklabel examples first.

Reviewed by:	wblock@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D3315
2015-09-02 14:08:43 +00:00
Edward Tomasz Napierala
3bb6078985 Whoops, wrong flag.
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
2015-08-06 07:49:34 +00:00
Edward Tomasz Napierala
6be30a3001 Tweak mdconfig(8) manual page, in particular revise the EXAMPLES
section.  This removes stuff that doesn't really belong there,
and simplifies examples for the basic operations.

Reviewed by:	wblock@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D3198
2015-08-06 07:47:13 +00:00
Baptiste Daroussin
bd0891ceb3 use .Mt to mark up email addresses consistently (part1)
PR:		191174
Submitted by:	Franco Fichtner  <franco@lastsummer.de>
2014-06-20 09:40:43 +00:00
Eitan Adler
dda5b39711 multiple: Remove 3rd clause from BSD license where approved by the
regents and renumber.

This patch skips files in contrib/ and crypto/

Acked by:	imp
Discussed with:	emaste
2014-03-14 03:07:51 +00:00
Edward Tomasz Napierala
0efd9bfd47 Add "null" backend to mdconfig(8). This does exactly what the name
suggests, and is somewhat useful for benchmarking.

MFC after:	1 month
No objections from:	kib
Sponsored by:	The FreeBSD Foundation
2013-12-04 07:38:23 +00:00
John-Mark Gurney
52a522a283 bump date forgotten in r257165 2013-10-26 18:23:43 +00:00
John-Mark Gurney
8cde1e8a69 Document that -a will output the device name when -u is not specified..
when -u is specified it is not...

update the docs to say that you can use full device names w/ -u, and
update the examples...

Submitted by:	#vbsdcon
MFC after:	3 days
2013-10-26 15:05:27 +00:00
Joel Dahl
a9ca77e055 mdoc: remove EOL whitespace. 2013-06-29 16:05:44 +00:00
Hiroki Sato
b78ae23fdd - Add "-f file" support to listing mode (-l). When a -f option is
specified, only md(4) devices which have the specified file as backing
  store are displayed.
- Use MD_NAME instead of "md".
- Use _PATH_DEV instead of "/dev/".

MFC after:	1 week
2013-06-20 14:30:16 +00:00
Warren Block
2f78ba90f4 Add an example showing the use of gnop(8) to skip over header data.
PR:		kern/145999
Reviewed by:	mjg
MFC after:	1 week
2012-11-04 03:19:07 +00:00
Edward Tomasz Napierala
dc604f0cf6 Make it possible to resize md(4) devices.
Reviewed by:	kib
Sponsored by:	FreeBSD Foundation
2012-07-07 20:32:21 +00:00
Gavin Atkinson
b45c4eb9ae The -S option, to specify the sector size, has been usable on all types of
memory disks since r135340.  Update the man page to reflect this.

Noticed by:	avg
MFC after:	3 days
2012-06-27 12:19:28 +00:00
Joel Dahl
4228c8a2b1 Remove end of line whitespace. 2012-05-12 19:59:37 +00:00
Joel Dahl
5da4420931 mdoc: use Po and Pc macros instead of parens. Also avoid starting a line
with Ns.
2012-05-12 17:14:55 +00:00
Benjamin Kaduk
ac5b109f31 Fix a couple of style issues. Tweak grammar and markup while here.
Approved by:	hrs (mentor)
2012-04-09 01:20:50 +00:00
Dag-Erling Smørgrav
6c49c6cff2 Somewhere around the 473rd time I mistyped "mdconfig file" instead of
"mdconfig -f file", I decided that it would be easier to make mdconfig
DWIM than to teach my fingers to type the correct command line.

MFC after:	3 weeks
2011-04-29 22:40:11 +00:00
Joel Dahl
db28020476 Use "cylinder" instead of "cyl" for consistency.
Reviewed by:	phk
2010-11-13 15:28:44 +00:00
Edward Tomasz Napierala
a9ebb31183 Add the possibility to specify "-o force" with "mdconfig -du".
Reviewed by:	scottl
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2009-01-10 17:17:18 +00:00
Dmitry Morozovsky
c94b8307db Add -v (verbose) option to -l command, to show size and backing store
of all md devices at one time.

Approved by:	phk
MFC after:	2 weeks
2008-06-21 15:04:42 +00:00
Remko Lodder
3655c14d25 Every newline should start on it's own line. I didn't do that in the
previous commit, so make it happen now.

Prodded by:	brueffer
2007-11-28 12:29:59 +00:00
Remko Lodder
d18e01346c Sync with md(4)'s information regarding the swap backend.
PR:		docs/115721
Submitted by:	Stefan Lambrev <stefan.lambrev@moneybookers.com>
MFC After:	3 days
2007-11-28 12:11:36 +00:00
Giorgos Keramidas
d257bc4a71 * Expand the example descriptions, fix mdoc-bugs in
"(-a and -t vnode are implied)"
  and reuse it near the cd9660 example.
* Spell 'backing store' as two words.
2007-11-11 08:12:21 +00:00
Giorgos Keramidas
284096f773 Instead of hardcoding md10 as the device node in the cd9660 example,
use a trick submitted by Ruslan.

MFC after:	1 day
2007-11-09 18:02:51 +00:00
Giorgos Keramidas
5810c7ef77 Add an example which shows how mdconfig(8) can be used
to mount an ISO 9660 CD image file.

PR:		112691
Submitted by:	Warren Block, wblock at wonkity.com
MFC after:	3 days
2007-05-18 13:57:17 +00:00
Nick Hibma
7090e3d10c Kris suggested that swap is a better choice as a default than malloc.
MFC:	1 week
2007-02-20 22:04:23 +00:00
Nick Hibma
35ce0ff2f2 [Found the original diff I made, see previous commit for other part]
Assume '-a' and '-t malloc' flags for '-s <size>' (malloc ramdisk) if not
specified.

Reviewed by:	phk (some time ago)
MFC:		1 week
2007-02-20 21:29:30 +00:00
Nick Hibma
1253fe1ead Make attach the default for -f. That way
mdconfig -f image

works like a charm.

Reviewed by:	phk (some time ago)
MFC:		1 week
2007-02-20 21:04:12 +00:00
Pawel Jakub Dawidek
0d79319a76 Allow to specify device size in bytes.
MFC after:	1 week
2005-01-22 20:02:01 +00:00
Dima Dorfman
df5f8fa751 Bump .Dd, replace missing letter, and prefer to use a verb that
matches the option letter.

Submitted by:	ru
Should know better by now:	dd
2004-11-06 14:03:37 +00:00
Dima Dorfman
e08f2053fc Update the description of -l to reflect reality. After mdconfig.c
1.25, -l without -u only lists the names, so specifying -u does more
than just limit the output to one device.
2004-11-06 10:21:12 +00:00
Pawel Jakub Dawidek
b830359bc5 - Make md(4) 64-bit clean.
After this change it should be possible to use very big md(4) devices.
- Clean up and simplify the code a bit.
- Use humanize_number(3) to print size of md(4) devices.
- Add 't' suffix which stands for terabyte.
- Make '-S' to really work with all types of devices.
- Other minor changes.
2004-09-16 21:32:13 +00:00
Ruslan Ermilov
9806e23132 Mechanically kill hard sentence breaks. 2004-07-02 21:45:06 +00:00
Ruslan Ermilov
d04b5dfe6c Assorted markup, grammar, and spelling fixes. 2004-05-17 08:35:43 +00:00
Poul-Henning Kamp
7a6b2b6429 Fix a long-standing deadlock issue with vnode backed md(4) devices:
On vnode backed md(4) devices over a certain, currently undetermined
size relative to the buffer cache our "lemming-syncer" can provoke
a buffer starvation which puts the md thread to sleep on wdrain.

This generally tends to grind the entire system to a stop because the
event that is supposed to wake up the thread will not happen until a fair
bit of the piled up I/O requests in the system finish, and since a lot
of those are on a md(4) vnode backed device which is currently waiting
on wdrain until a fair amount of the piled up ... you get the picture.

The cure is to issue all VOP_WRITES on the vnode backing the device
with IO_SYNC.

In addition to more closely emulating a real disk device with a
non-lying write-cache, this makes the writes exempt from rate-limited
(there to avoid starving the buffer cache) and consequently prevents
the deadlock.

Unfortunately performance takes a hit.

Add "async" option to give people who know what they are doing the
old behaviour.
2004-03-10 20:41:09 +00:00
Poul-Henning Kamp
91f9647d49 s/bytes/byte/ 2004-02-19 19:53:07 +00:00
Poul-Henning Kamp
79ae25f61f Note that geometry can also be specified on vnode backed deviecs. 2004-01-12 10:54:09 +00:00
Poul-Henning Kamp
b4bca2d5ec Warn that big malloc disks are a panic(8) implementation.
Submitted by:	Colin Percival <cperciva@builder.daemonology.net>
(Who should really get his own bit one of these days!)

PR:	59988
2004-01-02 14:28:06 +00:00
Marc Fonvieille
84783ceaeb Add a full example of a file-backed disk creation, I used the Handbook's
example.

PR:		docs/51897
Submitted by:	Kevin Oberman <oberman@es.net>
2003-10-11 09:59:25 +00:00
Marc Fonvieille
8b23842d38 s/disklabel/bsdlabel where needed. 2003-10-11 08:24:07 +00:00
Poul-Henning Kamp
076cb6a8c9 Document the -x and -y options. 2003-09-21 19:05:35 +00:00
Robert Watson
f79c46d3f4 Add "-n" argument, which causes mdconfig to simply print the unit
number X, rather than mdX, making it easier to script tests that
use md devices but don't want to make assumptions about any existing
md use (such as in diskless environments).
2003-06-11 06:38:24 +00:00
Doug Barton
1b6c6f4aae Add .Xr's to mdmfs(8).
Submitted by:	Scot W. Hetzel <hetzels@westbend.net>
2003-04-27 01:46:56 +00:00
Poul-Henning Kamp
ebe789d61c Add a "-S sectorsize" option to enable Kirk to find a bug :-) 2003-03-03 13:05:00 +00:00