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  1. 31 1月, 2014 1 次提交
    • M
      zram: promote zram from staging · cd67e10a
      由 Minchan Kim 提交于 
      Zram has lived in staging for a LONG LONG time and have been
fixed/improved by many contributors so code is clean and stable now.  Of
course, there are lots of product using zram in real practice.

The major TV companys have used zram as swap since two years ago and
recently our production team released android smart phone with zram
which is used as swap, too and recently Android Kitkat start to use zram
for small memory smart phone.  And there was a report Google released
their ChromeOS with zram, too and cyanogenmod have been used zram long
time ago.  And I heard some disto have used zram block device for tmpfs.
In addition, I saw many report from many other peoples.  For example,
Lubuntu start to use it.

The benefit of zram is very clear.  With my experience, one of the
benefit was to remove jitter of video application with backgroud memory
pressure.  It would be effect of efficient memory usage by compression
but more issue is whether swap is there or not in the system.  Recent
mobile platforms have used JAVA so there are many anonymous pages.  But
embedded system normally are reluctant to use eMMC or SDCard as swap
because there is wear-leveling and latency issues so if we do not use
swap, it means we can't reclaim anoymous pages and at last, we could
encounter OOM kill.  :(

Although we have real storage as swap, it was a problem, too.  Because
it sometime ends up making system very unresponsible caused by slow swap
storage performance.

Quote from Luigi on Google
 "Since Chrome OS was mentioned: the main reason why we don't use swap
  to a disk (rotating or SSD) is because it doesn't degrade gracefully
  and leads to a bad interactive experience.  Generally we prefer to
  manage RAM at a higher level, by transparently killing and restarting
  processes.  But we noticed that zram is fast enough to be competitive
  with the latter, and it lets us make more efficient use of the
  available RAM.  " and he announced.
http://www.spinics.net/lists/linux-mm/msg57717.html

Other uses case is to use zram for block device.  Zram is block device
so anyone can format the block device and mount on it so some guys on
the internet start zram as /var/tmp.
http://forums.gentoo.org/viewtopic-t-838198-start-0.html

Let's promote zram and enhance/maintain it instead of removing.
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NNitin Gupta <ngupta@vflare.org>
Acked-by: NPekka Enberg <penberg@kernel.org>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cd67e10a
  3. 04 12月, 2013 1 次提交
  5. 09 11月, 2013 1 次提交
  7. 25 10月, 2013 1 次提交
  9. 29 3月, 2013 1 次提交
  11. 27 3月, 2013 1 次提交
  13. 05 2月, 2013 1 次提交
  15. 05 1月, 2013 1 次提交
    • P
      block: delete super ancient PC-XT driver for 1980's hardware · d1a6f4f1
      由 Paul Gortmaker 提交于 
      This driver was for the 8 bit ISA cards that were installed in
the PC-XT machines of 1980 vintage.  They supported the dual
ribbon cable MFM drives of 10-20MB capacity, and ran at a 3:1
interleave, giving performance on the order of 128kB/s.

By the introduction of the PC-AT (286) these controllers were
already scrapped in favour of 16 bit controllers with some onboard
RAM that could support a 1:1 interleave.

The git history doesn't show any evidence of runtime fixes that
would reflect active usage; instead just the usual tree-wide API
type changes/cleanups.  Going back to in-source changelogs, the
last "runtime" fix that is evident is something I did over a
dozen years ago[1] -- and even back then, the hardware was long
since unavailable, so that ancient fix was also not runtime tested.

The time is long overdue for this to get flushed, so lets get
rid of it before anyone wastes more time doing builds and sparse
checks etc. on long since dead code.

[1] http://lkml.indiana.edu/hypermail/linux/kernel/0102.2/0027.htmlSigned-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      d1a6f4f1
  17. 06 9月, 2012 1 次提交
  19. 05 11月, 2011 2 次提交
  21. 19 4月, 2011 1 次提交
  23. 19 1月, 2011 1 次提交
  25. 21 10月, 2010 1 次提交
  27. 09 6月, 2010 1 次提交
  29. 07 6月, 2010 1 次提交
  31. 02 10月, 2009 1 次提交
  33. 24 6月, 2009 1 次提交
    • J
      osdblk: a Linux block device for OSD objects · 2a13877c
      由 Jeff Garzik 提交于 
      Submitted driver exports a block device of the form /dev/osdblkX,
where X is a decimal number.

It does that by mounting a stacking block device on top
of an osd object. For example, if you create a 2G object
on an OSD device, you can then use this module to present
that 2G object as a Linux block device.

See inside patch for exact documentation.

[Sitting at linux-next helped fix proper Kconfig dependency
 for this driver, thanks to Randy Dunlap]
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
      2a13877c
  35. 07 4月, 2009 1 次提交
    • U
      mflash: initial support · 3fbed4c6
      由 unsik Kim 提交于 
      This driver supports mflash IO mode for linux.

Mflash is embedded flash drive and mainly targeted mobile and consumer
electronic devices.

Internally, mflash has nand flash and other hardware logics and supports 2
different operation (ATA, IO) modes.  ATA mode doesn't need any new driver
and currently works well under standard IDE subsystem.  Actually it's one
chip SSD.  IO mode is ATA-like custom mode for the host that doesn't have
IDE interface.

Followings are brief descriptions about IO mode.
A. IO mode based on ATA protocol and uses some custom command. (read confirm,
write confirm)
B. IO mode uses SRAM bus interface.
C. IO mode supports 4kB boot area, so host can boot from mflash.

This driver is quitely similar to a standard ATA driver, but because of
following reasons it is currently seperated with ATA layer.

1. ATA layer deals standard ATA protocol.  ATA layer have many low-
   level device specific interface, but data transfer keeps ATA rule.
   But, mflash IO mode doesn't.

2. Even though currently not used in mflash driver code, mflash has
   some custom command and modes.  (nand fusing, firmware patch, etc) If
   this feature supported in linux kernel, ATA layer more altered.

3. Currently PATA platform device driver doesn't support interrupt.
   (I'm not sure) But, mflash uses interrupt (polling mode is just for
   debug).

4. mflash is somewhat under-develop product.  Even though some company
   already using mflash their own product, I think more time is needed for
   standardization of custom command and mode.  That time (maybe October)
   I will talk to with ATA people.  If they accept integration, I will
   integrate.
Signed-off-by: Nunsik Kim <donari75@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      3fbed4c6
  37. 27 3月, 2009 1 次提交
  39. 13 3月, 2009 1 次提交
  41. 17 7月, 2008 1 次提交
  43. 17 3月, 2008 1 次提交
  45. 09 2月, 2008 1 次提交
    • N
      rewrite rd · 9db5579b
      由 Nick Piggin 提交于 
      This is a rewrite of the ramdisk block device driver.

The old one is really difficult because it effectively implements a block
device which serves data out of its own buffer cache.  It relies on the dirty
bit being set, to pin its backing store in cache, however there are non
trivial paths which can clear the dirty bit (eg.  try_to_free_buffers()),
which had recently lead to data corruption.  And in general it is completely
wrong for a block device driver to do this.

The new one is more like a regular block device driver.  It has no idea about
vm/vfs stuff.  It's backing store is similar to the buffer cache (a simple
radix-tree of pages), but it doesn't know anything about page cache (the pages
in the radix tree are not pagecache pages).

There is one slight downside -- direct block device access and filesystem
metadata access goes through an extra copy and gets stored in RAM twice.
However, this downside is only slight, because the real buffercache of the
device is now reclaimable (because we're not playing crazy games with it), so
under memory intensive situations, footprint should effectively be the same --
maybe even a slight advantage to the new driver because it can also reclaim
buffer heads.

The fact that it now goes through all the regular vm/fs paths makes it
much more useful for testing, too.

   text    data     bss     dec     hex filename
   2837     849     384    4070     fe6 drivers/block/rd.o
   3528     371      12    3911     f47 drivers/block/brd.o

Text is larger, but data and bss are smaller, making total size smaller.

A few other nice things about it:
- Similar structure and layout to the new loop device handlinag.
- Dynamic ramdisk creation.
- Runtime flexible buffer head size (because it is no longer part of the
  ramdisk code).
- Boot / load time flexible ramdisk size, which could easily be extended
  to a per-ramdisk runtime changeable size (eg. with an ioctl).
- Can use highmem for the backing store.

[akpm@linux-foundation.org: fix build]
[byron.bbradley@gmail.com: make rd_size non-static]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NByron Bradley <byron.bbradley@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9db5579b
  47. 23 10月, 2007 2 次提交
    • R
      Remove old lguest bus and drivers. · 0ca49ca9
      由 Rusty Russell 提交于 
      This gets rid of the lguest bus, drivers and DMA mechanism, to make
way for a generic virtio mechanism.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      0ca49ca9
    • R
      Block driver using virtio. · e467cde2
      由 Rusty Russell 提交于 
      The block driver uses scatter-gather lists with sg[0] being the
request information (struct virtio_blk_outhdr) with the type, sector
and inbuf id.  The next N sg entries are the bio itself, then the last
sg is the status byte.  Whether the N entries are in or out depends on
whether it's a read or a write.

We accept the normal (SCSI) ioctls: they get handed through to the other
side which can then handle it or reply that it's unsupported.  It's
not clear that this actually works in general, since I don't know
if blk_pc_request() requests have an accurate rq_data_dir().

Although we try to reply -ENOTTY on unsupported commands, ioctl(fd,
CDROMEJECT) returns success to userspace.  This needs a separate
patch.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <jens.axboe@oracle.com>
      e467cde2
  49. 30 7月, 2007 1 次提交
  51. 22 7月, 2007 1 次提交
  53. 20 7月, 2007 1 次提交
  55. 18 7月, 2007 2 次提交
  57. 16 7月, 2007 2 次提交
  59. 10 7月, 2007 1 次提交
  61. 14 12月, 2006 1 次提交
  63. 24 3月, 2006 1 次提交
  65. 04 11月, 2005 1 次提交
  67. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4