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: Minchan Kim <minchan@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The drivers are long gone but some config escaped the prune
Signed-off-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=57221
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Pull block driver updates from Jens Axboe:
"This is the block driver pull request for 3.13. As with the core pull
request just sent out, this was rebased on top of the core branch
again after the immutable series was pulled. This also means that
bcache gets to sit the initial pull over. I will send a second driver
pull request in the merge window to get those fixes in, once they have
been rebased and tested on top of the non-immutable stack.
This pull request contains:
- Add support for the sTec Kronos pci-e flash card from sTec. Also
has various cleanups for this driver, from myself, Bart, Mike
Snizter, and Wei Yongjun.
- Add surprise removal support for the micron mtip32xx driver from
Micron.
- Floppy documentation fix from Ben Harris.
- debugfs bug fix for pktcdvd from Dan Carpenter.
- Fix for the mtip32xx driver stack usage in the debugfs path,
dynamically allocating those buffers instead. From David Milburn.
- Disable cpqarray in Kconfig. The plan is to remove it on request
of HP, but lets disable it for a few revisions just to see if
anyone yells.
- drbd fixes from Lars Ellenberg and Philipp Reisner.
- Elevator switch fix for the s390 block driver from Heiko Carstens.
- loop crash fix on IO to unassigned device from Mikulas Patocka.
- A series of bug fixes for the IBM rsxx pci-e flash driver from
Philip J Kelleher.
- cciss probe fix from Stephen Cameron.
- Xen block front/back fixes from Roger Pau Monne and Vegard Nossum"
* 'for-3.13/drivers' of git://git.kernel.dk/linux-block: (41 commits)
floppy: Correct documentation of driver options when used as a module.
pktcdvd: debugfs functions return NULL on error
xen-blkfront: restore the non-persistent data path
skd: fix formatting in skd_s1120.h
skd: reorder construct/destruct code
skd: cleanup skd_do_inq_page_da()
skd: remove SKD_OMIT_FROM_SRC_DIST ifdefs
skd: remove redundant skdev->pdev assignment from skd_pci_probe()
skd: use <asm/unaligned.h>
skd: remove SCSI subsystem specific includes
skd: register block device only if some devices are present
skd: fix error messages in skd_init()
skd: fix error paths in skd_init()
skd: fix unregister_blkdev() placement
skd: more removal of bio-based code
skd: cleanup the skd_*() function block wrapping
skd: rip out bio path
skd: fix error return code in skd_pci_probe()
s390/dasd: hold request queue sysfs lock when calling elevator_init()
cciss: return 0 from driver probe function on success, not 1
...
A driver that simply completes IO it receives, it does no
transfers. Written to fascilitate testing of the blk-mq code.
It supports various module options to use either bio queueing,
rq queueing, or mq mode.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Translates SCSI commands in SG_IO ioctl to NVMe commands.
Uses the scsi-nvme translation spec from nvmexpress.org as reference.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
In preparation for adding nvme-scsi.c
It is preferable to retain the module name 'nvme'
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Paul writes:
Please pull the following to get the removal of the original IBM PC-XT
hard disk driver from the block layer (drivers/block/xd.c).
As near as I can tell, it hasn't seen a run time fix in over a dozen
years, and with drive sizes of 10-20MB, and performance of about 128kB/s
maximum, it is no surprise that it has been completely unused for well
over a decade.
The removal was originally posted[1] well over a month ago, and since
then, there has been nobody objecting to the removal, aside from someone
who had mistakenly confused it with a completely different driver (hd.c)
This patch includes the device driver for the IBM RamSan
family of PCI SSD flash storage cards. This driver will
include support for the RamSan 70 and 80. The driver
presents a block device for device I/O.
Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.html
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
It was scheduled to be removed in 3.6.
Acked-by: Pete Zaitcev <zaitcev@redhat.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* git://git.infradead.org/users/willy/linux-nvme: (105 commits)
NVMe: Set number of queues correctly
NVMe: Version 0.8
NVMe: Set queue flags correctly
NVMe: Simplify nvme_unmap_user_pages
NVMe: Mark the end of the sg list
NVMe: Fix DMA mapping for admin commands
NVMe: Rename IO_TIMEOUT to NVME_IO_TIMEOUT
NVMe: Merge the nvme_bio and nvme_prp data structures
NVMe: Change nvme_completion_fn to take a dev
NVMe: Change get_nvmeq to take a dev instead of a namespace
NVMe: Simplify completion handling
NVMe: Update Identify Controller data structure
NVMe: Implement doorbell stride capability
NVMe: Version 0.7
NVMe: Don't probe namespace 0
Fix calculation of number of pages in a PRP List
NVMe: Create nvme_identify and nvme_get_features functions
NVMe: Fix memory leak in nvme_dev_add()
NVMe: Fix calls to dma_unmap_sg
NVMe: Correct sg list setup in nvme_map_user_pages
...
This adds mtip32xx, a driver supporting Microns line of
pci-express flash storage cards.
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Sam Bradshaw <sbradshaw@micron.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Change Makefile to use <modules>-y instead of <modules>-objs because -objs
is deprecated and should now be switched. According to
(documentation/kbuild/makefiles.txt).
Signed-off-by: Tracey Dent <tdent48227@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The rados block device (rbd), based on osdblk, creates a block device
that is backed by objects stored in the Ceph distributed object storage
cluster. Each device consists of a single metadata object and data
striped over many data objects.
The rbd driver supports read-only snapshots.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
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: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
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: unsik Kim <donari75@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
It allows to read data from a floppy, but not to write to, and to eject the
floppy (useful on our Mac without eject button).
Signed-off-by: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Convert the PS3 Video RAM Storage Driver from an MTD driver to a plain block
device driver.
The ps3vram driver exposes unused video RAM on the PS3 as a block device
suitable for storage or swap. Fast data transfer is achieved using a local
cache in system RAM and DMA transfers via the GPU.
The new driver is ca. 50% faster for reading, and ca. 10% for writing.
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch moves hd.c to drivers/block/
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: rmk@arm.linux.org.uk
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
no longer working for some time.
A driver that had been marked as BROKEN for such a long time seems to be
unlikely to be revived in the forseeable future.
But if anyone wants to ever revive this driver, the code is still present in
the older kernel releases.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Nick Piggin <npiggin@suse.de>
Signed-off-by: Byron Bradley <byron.bbradley@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This gets rid of the lguest bus, drivers and DMA mechanism, to make
way for a generic virtio mechanism.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <jens.axboe@oracle.com>
Gabriel C reports lguest doesn't compile with CONFIG_BLOCK=n. Fix this
by introducing a config var for the block device, which depends on
LGUEST && BLOCK. Do the same for the net driver, rather then depending
gratuitously on CONFIG_NET.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Gabriel C <nix.or.die@googlemail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a Disk Storage Driver for the PS3:
- Implemented as a block device driver with a dynamic major
- Disk names (and partitions) are of the format ps3d%c(%u)
- Uses software scatter-gather with a 64 KiB bounce buffer as the hypervisor
doesn't support scatter-gather
Cc: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The block device frontend driver allows the kernel to access block
devices exported exported by a virtual machine containing a physical
block device driver.
Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <axboe@kernel.dk>
Tested on Xilinx Virtex ppc405, Katmai 440SPe, and Microblaze
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Stefan Roese <sr@denx.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: John William <jwilliams@itee.uq.edu.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block:
splice: direct splicing updates ppos twice
more ACSI removal
umem: Fix match of pci_ids in umem driver
umem: Remove references to dead CONFIG_MM_MAP_MEMORY variable
remove the documentation for the legacy CDROM drivers
This patch removes some code that became dead code after the ATARI_ACSI
removal.
It also indirectly fixes the following bug introduced by
commit c2bcf3b8978c291e1b7f6499475c8403a259d4d6:
config ATARI_SLM
tristate "Atari SLM laser printer support"
- depends on ATARI && ATARI_ACSI!=n
+ depends on ATARI
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Originally from Boaz Harrosh <bharrosh@panasas.com>
It hasn't been working in 2.5 or 2.6 ever, since it's still buffer_head
based.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The BLK_DEV_SWIM_IOP driver has:
- already been marked as BROKEN in 2.6.0 three years ago and
- is still marked as BROKEN.
Drivers that had been marked as BROKEN for such a long time seem to be
unlikely to be revived in the forseeable future.
But if anyone wants to ever revive this driver, the code is still
present in the older kernel releases.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
floppy98 went out together with the rest of PC98 subarch. Remove stale
Makefile entry that remained.
Signed-off-by: Arthur Othieno <apgo@patchbomb.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
drivers/block/ is right now a mix of core and driver parts. Lets move
the core parts to a new top level directory. Al will move the fs/
related block parts to block/ next.
Signed-off-by: Jens Axboe <axboe@suse.de>
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!
Minchan Kim