Jens Axboe f35546e072 Merge branch 'stable/for-jens-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-3.11/drivers ... Konrad writes: It has the 'feature-max-indirect-segments' implemented in both backend and frontend. The current problem with the backend and frontend is that the segment size is limited to 11 pages. It means we can at most squeeze in 44kB per request. The ring can hold 32 (next power of two below 36) requests, meaning we can do 1.4M of outstanding requests. Nowadays that is not enough. The problem in the past was addressed in two ways - but neither one went upstream. The first solution to this proposed by Justin from Spectralogic was to negotiate the segment size. This means that the ‘struct blkif_sring_entry’ is now a variable size. It can expand from 112 bytes (cover 11 pages of data - 44kB) to 1580 bytes (256 pages of data - so 1MB). It is a simple extension by just making the array in the request expand from 11 to a variable size negotiated. But it had limits: this extension still limits the number of segments per request to 255 (as the total number must be specified in the request, which only has an 8-bit field for that purpose). The other solution (from Intel - Ronghui) was to create one extra ring that only has the ‘struct blkif_request_segment’ in them. The ‘struct blkif_request’ would be changed to have an index in said ‘segment ring’. There is only one segment ring. This means that the size of the initial ring is still the same. The requests would point to the segment and enumerate out how many of the indexes it wants to use. The limit is of course the size of the segment. If one assumes a one-page segment this means we can in one request cover ~4MB. Those patches were posted as RFC and the author never followed up on the ideas on changing it to be a bit more flexible. There is yet another mechanism that could be employed  (which these patches implement) - and it borrows from VirtIO protocol. And that is the ‘indirect descriptors’. This very similar to what Intel suggests, but with a twist. The twist is to negotiate how many of these 'segment' pages (aka indirect descriptor pages) we want to support (in reality we negotiate how many entries in the segment we want to cover, and we module the number if it is bigger than the segment size). This means that with the existing 36 slots in the ring (single page) we can cover: 32 slots * each blkif_request_indirect covers: 512 * 4096 ~= 64M. Since we ample space in the blkif_request_indirect to span more than one indirect page, that number (64M) can be also multiplied by eight = 512MB. Roger Pau Monne took the idea and implemented them in these patches. They work great and the corner cases (migration between backends with and without this extension) work nicely. The backend has a limit right now off how many indirect entries it can handle: one indirect page, and at maximum 256 entries (out of 512 - so 50% of the page is used). That comes out to 32 slots * 256 entries in a indirect page * 1 indirect page per request * 4096 = 32MB. This is a conservative number that can change in the future. Right now it strikes a good balance between giving excellent performance, memory usage in the backend, and balancing the needs of many guests. In the patchset there is also the split of the blkback structure to be per-VBD. This means that the spinlock contention we had with many guests trying to do I/O and all the blkback threads hitting the same lock has been eliminated. Also there are bug-fixes to deal with oddly sized sectors, insane amounts on th ring, and also a security fix (posted earlier).		2013-06-28 16:01:14 +02:00
..
ABI	Merge branch 'stable/for-jens-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-3.11/drivers	2013-06-28 16:01:14 +02:00
DocBook	sound updates for v3.10-rc1	2013-05-03 09:10:23 -07:00
EDID	drm: Add 1600x1200 (UXGA) screen resolution to the built-in EDIDs	2013-04-12 14:06:16 +10:00
PCI	PCI/MSI: Enable multiple MSIs with pci_enable_msi_block_auto()	2013-01-24 17:25:13 +01:00
RCU	Merge commit '8700c95adb03' into timers/nohz	2013-05-02 17:54:19 +02:00
accounting	doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c	2012-11-26 14:22:21 +01:00
acpi	Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma	2013-05-09 09:46:45 -07:00
aoe	aoe: allow user to disable target failure timeout	2012-12-17 17:15:25 -08:00
arm	ARM: platform specific firmware interfaces for 3.10	2013-05-04 12:33:36 -07:00
arm64	arm64: Add simple earlyprintk support	2013-01-22 17:51:01 +00:00
auxdisplay	…
backlight	backlight: lp855x: remove duplicate platform data	2013-04-29 18:28:19 -07:00
blackfin	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
block	Documentation: cfq-iosched: update documentation help for cfq tunables	2013-04-09 14:57:06 +02:00
blockdev	nbd: update documentation and link to mailinglist	2013-02-27 19:10:22 -08:00
bus-devices	ARM: OMAP2+: gpmc: generic timing calculation	2012-11-09 18:07:11 +05:30
cdrom	doc: fix broken references	2011-09-27 18:08:04 +02:00
cgroups	blk-throttle: implement proper hierarchy support	2013-05-14 13:52:38 -07:00
connector	connector: Move cn_test.c away from NLMSG_PUT().	2012-06-26 21:19:02 -07:00
console	…
cpu-freq	Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-05-05 13:23:27 -07:00
cpuidle	cpuidle: make a single register function for all	2013-04-23 13:45:22 +02:00
cris	CRIS: Update documentation	2012-04-03 13:09:18 +02:00
crypto	KEYS: Document asymmetric key type	2012-10-08 13:50:12 +10:30
development-process	Documentation: Update stable address	2011-12-12 14:14:31 -08:00
device-mapper	DM RAID: Add message/status support for changing sync action	2013-04-24 11:42:43 +10:00
devicetree	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2013-05-10 07:48:05 -07:00
driver-model	lib: devres: Introduce devm_ioremap_resource()	2013-01-22 09:41:43 -08:00
dvb	[media] get_dvb_firmware: Fix the location of firmware for Terratec HTC	2013-01-01 11:18:26 -02:00
early-userspace	…
extcon	Documentation/extcon: porting guide for Android kernel switch driver.	2012-04-20 09:24:27 -07:00
fault-injection	doc: fix quite a few typos within Documentation	2012-11-19 14:28:24 +01:00
fb	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
filesystems	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2013-05-09 13:07:40 -07:00
firmware_class	firmware loader: document firmware cache mechanism	2012-11-14 15:07:18 -08:00
frv	doc: fix broken references	2011-09-27 18:08:04 +02:00
hid	HID: remove x bit from sensor doc	2012-12-14 08:48:59 +01:00
hwmon	hwmon: (lm75) Add support for the Dallas/Maxim DS7505	2013-05-04 14:49:36 +02:00
i2c	i2c: Fix my e-mail address in drivers and documentation	2013-03-22 11:18:34 +01:00
i2o	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
ia64	Fix example error_injection_tool	2013-04-02 09:39:55 -07:00
ide	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
infiniband	IB/ipoib: Add rtnl_link_ops support	2012-09-20 16:49:17 -04:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2013-03-11 07:49:37 -07:00
ioctl	USB: cdc-wdm: implement IOCTL_WDM_MAX_COMMAND	2013-03-25 13:32:20 -07:00
isdn	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
ja_JP	…
kbuild	Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2013-05-07 07:59:19 -07:00
kdump	Add size restriction to the kdump documentation	2013-04-02 09:40:03 -07:00
ko_KR	driver-core: documentation: fix up Greg's email address	2012-02-15 14:48:01 -08:00
laptops	Documentation/laptops: remove depends on CONFIG_EXPERIMENTAL	2013-01-21 14:52:42 -08:00
leds	leds: lp55xx: configure the clock detection	2013-04-01 11:04:53 -07:00
m68k	…
make	…
memory-devices	memory: emif: add basic infrastructure for EMIF driver	2012-05-02 00:10:49 -07:00
metag	metag: Basic documentation	2013-03-02 20:09:50 +00:00
mips	…
misc-devices	mei: bus: Add device enabling and disabling API	2013-04-08 16:57:15 -07:00
mmc	mmc: core: Add in support to expose PRV for v4 MMCs	2013-03-22 12:10:42 -04:00
mn10300	…
mtd	…
namespaces	userns: Recommend use of memory control groups.	2013-01-26 22:20:06 -08:00
netlabel	…
networking	packet: doc: update timestamping part	2013-04-25 01:22:22 -04:00
nfc	NFC: Update pn544 documentation	2013-01-10 01:27:46 +01:00
parisc	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
pcmcia	…
power	PM / OPP: improve introductory documentation	2013-03-04 14:23:11 +01:00
powerpc	powerpc/ptrace: Add DAWR debug feature info for userspace	2013-04-18 15:59:55 +10:00
pps	…
prctl	seccomp: Make syscall skipping and nr changes more consistent	2012-10-02 21:14:29 +10:00
pti	…
ptp	…
rapidio	RapidIO: documentation update	2011-11-02 16:07:02 -07:00
s390	s390/cio: add condev keyword to cio_ignore	2013-05-02 15:50:20 +02:00
scheduler	sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW	2012-09-13 16:52:04 +02:00
scsi	[SCSI] qla2xxx: Update copyright dates information in LICENSE.qla2xxx file.	2013-04-06 11:31:30 +01:00
security	Smack: add support for modification of existing rules	2013-03-19 14:16:42 -07:00
serial	tty: Update serial core API documentation	2013-01-15 21:57:44 -08:00
sh	…
sound	ASoC: Updates for v3.10	2013-04-15 19:45:16 +02:00
spi	Documentation: remove __dev* attributes.	2013-01-03 15:57:16 -08:00
sysctl	mm: replace hardcoded 3% with admin_reserve_pages knob	2013-04-29 15:54:36 -07:00
target	target: Simplify fabric sense data length handling	2012-09-17 17:12:58 -07:00
thermal	Thermal: update documentation for thermal_zone_device_register	2013-04-27 09:16:04 +08:00
timers	nohz_full: Add documentation.	2013-04-27 16:41:43 -07:00
trace	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
usb	USB: remove CONFIG_USB_SUSPEND from Documentation	2013-03-28 14:45:56 -07:00
vDSO	…
video4linux	[media] v4l2: Add a V4L2 driver for SI476X MFD	2013-04-18 21:20:34 -03:00
virtual	Merge tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2013-05-05 14:47:31 -07:00
vm	mm: limit growth of 3% hardcoded other user reserve	2013-04-29 15:54:36 -07:00
w1	w1: w1_therm: Add force-pullup option for "broken" sensors	2013-02-18 13:55:24 -08:00
watchdog	watchdog: core: dt: add support for the timeout-sec dt property	2013-03-01 12:48:36 +01:00
wimax	…
x86	Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-04-30 08:35:20 -07:00
xtensa	xtensa: document MMUv3 setup sequence	2013-05-09 01:07:09 -07:00
zh_CN	gpio: update gpio Chinese documentation	2013-04-16 18:47:22 +09:00
.gitignore	…
00-INDEX	ImgTec Meta architecture changes for v3.9-rc1	2013-03-03 12:06:09 -08:00
BUG-HUNTING	…
Changes	…
CodingStyle	Documentation: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:38:03 -08:00
DMA-API-HOWTO.txt	Documentation/DMA-API-HOWTO.txt: fix typo	2013-02-27 19:10:23 -08:00
DMA-API.txt	dma-debug: New interfaces to debug dma mapping errors	2012-10-24 17:06:43 +02:00
DMA-ISA-LPC.txt	…
DMA-attributes.txt	common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute	2012-11-29 03:30:34 -08:00
HOWTO	HOWTO: fix double words typo	2012-12-10 15:54:27 +01:00
IPMI.txt	ipmi: add options to disable openfirmware and PCI scanning	2013-02-27 19:10:21 -08:00
IRQ-affinity.txt	…
IRQ-domain.txt	irqdomain: update documentation	2012-12-05 23:52:10 +00:00
IRQ.txt	…
Intel-IOMMU.txt	…
Makefile	mei: move doc files Documentation/misc-devices/mei	2012-05-09 13:59:09 -07:00
ManagementStyle	Documentation: ManagementStyle: fixed typo	2012-06-28 12:03:15 +02:00
SAK.txt	…
SM501.txt	…
SecurityBugs	…
SubmitChecklist	…
SubmittingDrivers	…
SubmittingPatches	checkpatch: add Suggested-by as a standard signature	2013-04-29 18:28:20 -07:00
VGA-softcursor.txt	…
applying-patches.txt	…
atomic_ops.txt	Documentation: Memory barrier semantics of atomic_xchg()	2013-01-08 14:14:55 -08:00
bad_memory.txt	…
basic_profiling.txt	…
bcache.txt	bcache: Documentation updates	2013-04-08 13:33:48 -07:00
binfmt_misc.txt	…
braille-console.txt	…
bt8xxgpio.txt	…
btmrvl.txt	…
bus-virt-phys-mapping.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
cachetlb.txt	…
circular-buffers.txt	…
clk.txt	clk: add clk_ignore_unused option to keep boot clocks on	2013-04-27 23:03:43 -07:00
coccinelle.txt	Coccinelle: Add support to the SPFLAGS variable	2013-04-08 15:42:03 +02:00
cpu-hotplug.txt	doc: Add x86 CPU0 online/offline feature	2012-11-14 09:39:44 -08:00
cpu-load.txt	…
cputopology.txt	…
crc32.txt	crc32: move long comment about crc32 fundamentals to Documentation/	2012-03-23 16:58:37 -07:00
dcdbas.txt	…
debugging-modules.txt	…
debugging-via-ohci1394.txt	…
dell_rbu.txt	…
devices.txt	firmware: remove last vestiges of dabusb	2012-11-21 13:03:01 -08:00
digsig.txt	crypto: digital signature verification support	2011-11-09 12:10:37 +02:00
dma-buf-sharing.txt	dma-buf: replace dma_buf_export() with dma_buf_export_named()	2013-05-01 16:35:36 +05:30
dmaengine.txt	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
dmatest.txt	dmatest: append verify result to results	2013-04-15 09:51:18 +05:30
dontdiff	x86: remove offsets.h from .gitignore and dontdiff	2012-11-19 14:10:53 +01:00
dynamic-debug-howto.txt	dynamic_debug: dynamic hex dump	2013-01-17 12:19:09 -08:00
edac.txt	Merge branch 'devel'	2012-07-29 21:11:05 -03:00
eisa.txt	MCA: delete all remaining traces of microchannel bus support.	2012-05-17 19:06:13 -04:00
email-clients.txt	…
flexible-arrays.txt	…
futex-requeue-pi.txt	…
gcov.txt	…
gpio.txt	Remove GENERIC_GPIO config option	2013-04-16 18:47:19 +09:00
highuid.txt	…
hw_random.txt	hwrng: Fix a wrong comment in Documentation/hw_random.txt	2013-03-10 18:16:36 +08:00
hwspinlock.txt	hwspinlock/core: register a bank of hwspinlocks in a single API call	2011-09-21 19:45:34 +03:00
init.txt	…
initrd.txt	Documentation/initrd.txt: Change the location of util-linux	2012-05-25 16:18:34 +02:00
intel_txt.txt	Documentation: remove depends on CONFIG_EXPERIMENTAL	2013-01-11 11:38:03 -08:00
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	iostats.txt: add easy-to-find description for field 6	2013-04-29 15:18:50 +02:00
irqflags-tracing.txt	…
isapnp.txt	…
java.txt	…
kernel-doc-nano-HOWTO.txt	Kernel-doc: Convention: Use a "Return" section to describe return values	2012-11-27 21:08:57 +01:00
kernel-docs.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
kernel-parameters.txt	IOMMU Updates for Linux v3.10	2013-05-06 14:59:13 -07:00
kmemcheck.txt	…
kmemleak.txt	kmemleak: Handle percpu memory allocation	2011-12-02 16:12:42 +00:00
kobject.txt	Documentation: Fix "struct kobj_type" to include newer members.	2012-09-04 16:06:34 -07:00
kprobes.txt	…
kref.txt	kref: Add kref_get_unless_zero documentation	2012-11-28 18:36:06 +10:00
ldm.txt	…
local_ops.txt	…
lockdep-design.txt	lockdep: Update documentation for lock-class leak detection	2011-12-11 10:31:23 -08:00
lockstat.txt	locking/stat: Fix a typo	2013-02-19 08:42:37 +01:00
lockup-watchdogs.txt	watchdog: Update documentation	2012-02-11 15:11:28 +01:00
logo.gif	…
logo.txt	…
magic-number.txt	wanrouter: completely decouple obsolete code from kernel.	2013-01-31 19:20:33 -05:00
md.txt	MD: Fix typos in MD documentation	2013-04-24 11:42:42 +10:00
media-framework.txt	[media] Documentation/media-framework.txt: fix a sentence	2013-02-08 13:27:13 -02:00
memory-barriers.txt	Documentation: Memory barrier semantics of atomic_xchg()	2013-01-08 14:14:55 -08:00
memory-hotplug.txt	hotplug: update nodemasks management	2012-12-12 17:38:33 -08:00
mono.txt	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
mutex-design.txt	…
nommu-mmap.txt	…
numastat.txt	Doc: Update numastat.txt	2012-02-28 16:05:06 +01:00
oops-tracing.txt	module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree	2011-11-07 07:54:42 +10:30
padata.txt	…
parport-lowlevel.txt	…
parport.txt	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
percpu-rw-semaphore.txt	percpu-rw-semaphore: fix documentation typos	2012-09-26 19:56:15 +02:00
pi-futex.txt	…
pinctrl.txt	pinctrl: document the "GPIO mode" pitfall	2013-03-18 11:03:29 +01:00
pnp.txt	…
preempt-locking.txt	…
printk-formats.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 13:47:37 -07:00
pwm.txt	pwm: add devm_pwm_get() and devm_pwm_put()	2012-09-10 17:05:45 +02:00
ramoops.txt	pstore/ftrace: Convert to its own enable/disable debugfs knob	2012-09-06 22:16:58 -07:00
rbtree.txt	rbtree: move augmented rbtree functionality to rbtree_augmented.h	2012-10-09 16:22:40 +09:00
remoteproc.txt	remoteproc: add rproc_report_crash function to notify rproc crashes	2012-09-18 12:53:22 +03:00
rfkill.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	Documentation: remove __dev* attributes.	2013-01-03 15:57:16 -08:00
rt-mutex-design.txt	…
rt-mutex.txt	…
rtc.txt	rtc-proc: permit the /proc/driver/rtc device to use other devices	2012-10-06 03:05:01 +09:00
serial-console.txt	…
sgi-ioc4.txt	…
sgi-visws.txt	…
smsc_ece1099.txt	mfd: smsc: Add support for smsc gpio io/keypad driver	2012-10-01 15:27:48 +02:00
sparse.txt	Documentation/sparse.txt: document context annotations for lock checking	2012-12-17 17:15:23 -08:00
spinlocks.txt	…
stable_api_nonsense.txt	…
stable_kernel_rules.txt	stable: Allow merging of backports for serious user-visible performance issues	2012-06-25 12:11:58 -07:00
static-keys.txt	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
svga.txt	…
sysfs-rules.txt	…
sysrq.txt	Documentation/sysrq: fix inconstistent help message of sysrq key	2013-04-30 17:04:10 -07:00
this_cpu_ops.txt	percpu: add documentation on this_cpu operations	2013-04-04 10:24:53 -07:00
unaligned-memory-access.txt	…
unicode.txt	…
unshare.txt	…
vfio.txt	vfio: Trivial Documentation correction	2012-09-21 10:48:03 -06:00
vgaarbiter.txt	misc latin1 to utf8 conversions	2012-01-02 13:04:55 +01:00
video-output.txt	…
vme_api.txt	VME: Move API documentation to Documentation folder	2012-05-08 16:01:34 -07:00
volatile-considered-harmful.txt	…
workqueue.txt	workqueue: reimplement WQ_HIGHPRI using a separate worker_pool	2012-07-13 22:24:45 -07:00
xz.txt	…
zorro.txt	…