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Tejun Heo a051661ca6 blkcg: implement per-blkg request allocation ... Currently, request_queue has one request_list to allocate requests from regardless of blkcg of the IO being issued. When the unified request pool is used up, cfq proportional IO limits become meaningless - whoever grabs the next request being freed wins the race regardless of the configured weights. This can be easily demonstrated by creating a blkio cgroup w/ very low weight, put a program which can issue a lot of random direct IOs there and running a sequential IO from a different cgroup. As soon as the request pool is used up, the sequential IO bandwidth crashes. This patch implements per-blkg request_list. Each blkg has its own request_list and any IO allocates its request from the matching blkg making blkcgs completely isolated in terms of request allocation. * Root blkcg uses the request_list embedded in each request_queue, which was renamed to @q->root_rl from @q->rq. While making blkcg rl handling a bit harier, this enables avoiding most overhead for root blkcg. * Queue fullness is properly per request_list but bdi isn't blkcg aware yet, so congestion state currently just follows the root blkcg. As writeback isn't aware of blkcg yet, this works okay for async congestion but readahead may get the wrong signals. It's better than blkcg completely collapsing with shared request_list but needs to be improved with future changes. * After this change, each block cgroup gets a full request pool making resource consumption of each cgroup higher. This makes allowing non-root users to create cgroups less desirable; however, note that allowing non-root users to directly manage cgroups is already severely broken regardless of this patch - each block cgroup consumes kernel memory and skews IO weight (IO weights are not hierarchical). v2: queue-sysfs.txt updated and patch description udpated as suggested by Vivek. v3: blk_get_rl() wasn't checking error return from blkg_lookup_create() and may cause oops on lookup failure. Fix it by falling back to root_rl on blkg lookup failures. This problem was spotted by Rakesh Iyer <rni@google.com>. v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in request waitqueue". blk_drain_queue() now wakes up waiters on all blkg->rl on the target queue. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2012-06-26 18:42:49 -04:00
..
ABI	mtip32xx: Remove 'registers' and 'flags' from sysfs	2012-06-05 09:13:48 +02:00
DocBook	- More robust parsing especially of xattr data in JFFS2	2012-06-01 16:55:42 -07:00
EDID	drm: allow loading an EDID as firmware to override broken monitor	2012-03-20 10:09:28 +00:00
PCI	doc: fix broken references	2011-09-27 18:08:04 +02:00
RCU	rcu: Introduce rcutorture testing for rcu_barrier()	2012-04-30 10:48:18 -07:00
accounting	Documentation: update cgroupfs mount point	2011-06-15 21:52:50 -07:00
acpi	Update documentation for parameter *notrigger* in einj.txt	2012-03-30 03:30:19 -04:00
aoe	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
arm	fbdev updates for 3.5	2012-06-01 16:57:51 -07:00
auxdisplay	…
backlight	backlight: new backlight driver for LP855x devices	2012-03-23 16:58:33 -07:00
blackfin	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
block	blkcg: implement per-blkg request allocation	2012-06-26 18:42:49 -04:00
blockdev	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
cdrom	doc: fix broken references	2011-09-27 18:08:04 +02:00
cgroups	memcg: move charges to root cgroup if use_hierarchy=0	2012-05-29 16:22:27 -07:00
connector	…
console	…
cpu-freq	Doc: cpufreq: Fix typo and outdated line	2011-11-08 10:23:29 +01:00
cpuidle	cpuidle: add a sysfs entry to disable specific C state for debug purpose.	2012-03-30 01:52:58 -04:00
cris	CRIS: Update documentation	2012-04-03 13:09:18 +02:00
crypto	…
development-process	Documentation: Update stable address	2011-12-12 14:14:31 -08:00
device-mapper	dm thin: provide userspace access to pool metadata	2012-06-03 00:30:01 +01:00
devicetree	- More robust parsing especially of xattr data in JFFS2	2012-06-01 16:55:42 -07:00
driver-model	Pin control subsystem changes for kernel 3.5:	2012-05-21 16:58:23 -07:00
dvb	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2012-05-24 10:21:51 -07:00
early-userspace	…
extcon	Documentation/extcon: porting guide for Android kernel switch driver.	2012-04-20 09:24:27 -07:00
fault-injection	fault-injection: update documentation with the mmc module param	2011-10-26 16:32:13 -04:00
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/viro/vfs	2012-06-01 10:34:35 -07:00
firmware_class	…
frv	doc: fix broken references	2011-09-27 18:08:04 +02:00
hid	HID: Move hiddev.txt to the new Documentation/hid directory	2011-03-22 11:43:51 +01:00
hwmon	hwmon updates for 3.5-rc1	2012-05-23 14:15:09 -07:00
i2c	i2c: Split I2C_M_NOSTART support out of I2C_FUNC_PROTOCOL_MANGLING	2012-05-30 10:55:34 +02:00
i2o	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
ia64	Fix common misspellings	2011-03-31 11:26:23 -03:00
ide	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
infiniband	…
input	Documentation: input.txt: clarify mousedev 'cat' command syntax	2012-03-30 16:03:15 -07:00
ioctl	mei: update Documentation/ioctl/ioctl-number.txt	2012-05-09 14:00:31 -07:00
isdn	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
ja_JP	Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6	2011-07-25 23:06:24 -07:00
kbuild	Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild	2012-05-28 10:37:56 -07:00
kdump	[S390] Add s390x description to Documentation/kdump/kdump.txt	2011-12-27 11:27:13 +01:00
ko_KR	driver-core: documentation: fix up Greg's email address	2012-02-15 14:48:01 -08:00
laptops	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
leds	leds: add new transient trigger for one shot timer activation	2012-05-29 16:22:32 -07:00
m68k	Documentation: add pointer to name_to_dev_t for root= values	2011-08-03 14:25:21 -10:00
make	…
memory-devices	memory: emif: add basic infrastructure for EMIF driver	2012-05-02 00:10:49 -07:00
mips	Fix common misspellings	2011-03-31 11:26:23 -03:00
misc-devices	mei: Documentation: add generated example binary into .gitignore file	2012-05-14 15:43:44 -07:00
mmc	mmc: core: Fixup delayed work clock gating patch	2012-01-11 23:58:43 -05:00
mn10300	…
mtd	…
namespaces	…
netlabel	…
networking	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2012-05-22 19:22:50 -07:00
nfc	NFC: Update Documentation/nfc-hci.txt	2012-05-15 17:28:01 -04:00
parisc	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
pcmcia	…
power	A bunch of fixes for v3.5, nothing extraordinary.	2012-05-31 12:10:15 -07:00
powerpc	Revert "powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags"	2012-05-22 14:37:24 +10:00
pps	pps: add parallel port PPS signal generator	2011-01-13 08:03:21 -08:00
prctl	Documentation: prctl/seccomp_filter	2012-04-14 11:13:22 +10:00
pti	Kernel documentation for the PTI feature.	2011-05-13 16:31:00 -07:00
ptp	ptp: Added a brand new class driver for ptp clocks.	2011-05-23 13:01:00 -07:00
rapidio	RapidIO: documentation update	2011-11-02 16:07:02 -07:00
s390	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
scheduler	sched: Remove stale power aware scheduling remnants and dysfunctional knobs	2012-05-17 13:48:56 +02:00
scsi	Merge branch 'delete-mca' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux	2012-05-23 17:12:06 -07:00
security	Smack: allow for significantly longer Smack labels v4	2012-05-14 22:48:38 -07:00
serial	serial: delete the MCA specific 8250 support.	2012-05-17 19:02:14 -04:00
sh	…
sound	Sound updates for 3.5-rc1	2012-05-23 13:05:43 -07:00
spi	spi: create a message queueing infrastructure	2012-03-07 19:19:48 -07:00
sysctl	mqueue: separate mqueue default value from maximum value	2012-05-31 17:49:31 -07:00
target	Documentation: Fix typo in tcm_mod_builder.py	2012-02-10 09:52:18 +01:00
telephony	Fix common misspellings	2011-03-31 11:26:23 -03:00
thermal	thermal: Rename generate_netlink_event	2012-01-23 03:15:25 -05:00
timers	doc: fix broken references	2011-09-27 18:08:04 +02:00
trace	tracing: Fix kconfig warning due to a typo	2012-05-08 14:17:25 +02:00
usb	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2012-05-22 19:22:50 -07:00
vDSO	Document the vDSO and add a reference parser	2011-07-14 17:57:09 -07:00
video4linux	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2012-05-24 10:21:51 -07:00
virtual	Merge branch 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2012-05-24 16:17:30 -07:00
vm	Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux	2012-06-01 16:50:23 -07:00
w1	Fix common misspellings	2011-03-31 11:26:23 -03:00
watchdog	Watchdog: DA9052/53 PMIC watchdog support	2012-05-30 07:56:12 +02:00
wimax	…
x86	x86, efi: Add EFI boot stub documentation	2012-06-01 09:11:41 -07:00
zh_CN	Fix a mistake sentence in the file 'Documentation/zh_CN/magic-number.txt'	2012-05-07 17:20:27 -07:00
.gitignore	…
00-INDEX	MCA: delete all remaining traces of microchannel bus support.	2012-05-17 19:06:13 -04:00
BUG-HUNTING	…
Changes	Documentation/Changes: remove some really obsolete text	2011-07-11 16:48:38 -07:00
CodingStyle	CodingStyle: add kmalloc_array() to memory allocators	2012-05-31 17:49:26 -07:00
DMA-API-HOWTO.txt	Documentation/DMA-API-HOWTO.txt: fix misleading example	2011-07-26 16:49:45 -07:00
DMA-API.txt	include/linux/dma-mapping.h: add dma_zalloc_coherent()	2011-11-02 16:07:02 -07:00
DMA-ISA-LPC.txt	…
DMA-attributes.txt	common: DMA-mapping: add NON-CONSISTENT attribute	2012-03-28 16:36:44 +02:00
HOWTO	docs: update HOWTO for 2.6.x -> 3.x versioning	2012-04-19 19:13:08 -07:00
IPMI.txt	…
IRQ-affinity.txt	bitmap, irq: add smp_affinity_list interface to /proc/irq	2011-05-25 08:39:45 -07:00
IRQ-domain.txt	irq_domain: add documentation and MAINTAINERS entry.	2012-02-14 14:06:47 -07:00
IRQ.txt	…
Intel-IOMMU.txt	…
Makefile	mei: move doc files Documentation/misc-devices/mei	2012-05-09 13:59:09 -07:00
ManagementStyle	…
SAK.txt	…
SM501.txt	…
SecurityBugs	Fix common misspellings	2011-03-31 11:26:23 -03:00
SubmitChecklist	Documentation/SubmitChecklist: add RCU debug config options	2011-07-25 20:57:17 -07:00
SubmittingDrivers	Documentation: SubmittingDrivers: fix Linus's git tree URL	2011-08-13 18:34:03 -07:00
SubmittingPatches	Documentation/SubmittingPatches: suggested the use of scripts/get_maintainer.pl	2012-05-25 16:18:30 +02:00
VGA-softcursor.txt	…
applying-patches.txt	…
atomic_ops.txt	doc: Add load/store guarantees to Documentation/atomic-ops.txt	2011-12-11 10:31:58 -08:00
bad_memory.txt	…
basic_profiling.txt	…
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	mm: convert mm->cpu_vm_cpumask into cpumask_var_t	2011-05-25 08:39:21 -07:00
circular-buffers.txt	…
clk.txt	Documentation: common clk API	2012-03-16 20:35:01 +00:00
coccinelle.txt	coccinelle.txt: update documentation to include M= option	2012-01-14 22:25:56 +01:00
cpu-hotplug.txt	documentation: remove references to cpu_*_map.	2012-03-29 15:38:31 +10:30
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	Fix common misspellings	2011-03-31 11:26:23 -03:00
devices.txt	Merge branch 'delete-mca' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux	2012-05-23 17:12:06 -07:00
digsig.txt	crypto: digital signature verification support	2011-11-09 12:10:37 +02:00
dma-buf-sharing.txt	dma-buf: add initial vmap documentation	2012-05-25 12:51:11 +05:30
dmaengine.txt	Documentation: Fix multiple typo in Documentation	2012-03-07 16:08:24 +01:00
dontdiff	Documentation: remove 'mach' from dontdiff file	2012-03-30 16:03:15 -07:00
dynamic-debug-howto.txt	dynamic_debug: update Documentation/*, Kconfig.debug	2012-04-30 16:26:30 -04:00
edac.txt	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
eisa.txt	MCA: delete all remaining traces of microchannel bus support.	2012-05-17 19:06:13 -04:00
email-clients.txt	Documentation: email-clients: Add better Thunderbird information	2011-08-13 18:34:03 -07:00
feature-removal-schedule.txt	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2012-05-31 10:32:36 -07:00
flexible-arrays.txt	flex_array: flex_array_prealloc takes a number of elements, not an end	2011-04-28 16:12:47 -04:00
futex-requeue-pi.txt	…
gcov.txt	…
gpio.txt	gpio: add flags to export GPIOs when requesting	2012-04-05 21:24:06 -07:00
highuid.txt	…
hw_random.txt	…
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	…
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	Documentation/iostats.txt: bit-size reference etc.	2011-03-23 20:44:18 +01:00
irqflags-tracing.txt	Fix common misspellings	2011-03-31 11:26:23 -03:00
isapnp.txt	…
java.txt	…
kernel-doc-nano-HOWTO.txt	…
kernel-docs.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
kernel-parameters.txt	IOMMU Updates for Linux 3.5	2012-05-30 08:49:28 -07:00
kmemcheck.txt	…
kmemleak.txt	kmemleak: Handle percpu memory allocation	2011-12-02 16:12:42 +00:00
kobject.txt	driver-core: documentation: fix up Greg's email address	2012-02-15 14:48:01 -08:00
kprobes.txt	…
kref.txt	kref: Fix typo in kref documentation	2011-03-07 13:20:05 -08:00
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	Documentation: Add statistics about nested locks	2011-05-28 17:03:29 +02:00
lockup-watchdogs.txt	watchdog: Update documentation	2012-02-11 15:11:28 +01:00
logo.gif	…
logo.txt	…
magic-number.txt	drivers/net: fix up stale paths from driver reorg	2012-01-30 12:54:40 -05:00
md.txt	md: create externally visible flags for supporting hot-replace.	2011-12-23 10:17:51 +11:00
media-framework.txt	[media] media: Add link_validate() op to check links to the sink pad	2012-05-14 08:44:11 -03:00
memory-barriers.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
memory-hotplug.txt	Documentation: Fix typo in multiple files in Documentation	2012-04-16 14:37:13 +02:00
memory.txt	…
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
pi-futex.txt	…
pinctrl.txt	pinctrl: implement devm_pinctrl_get()/put()	2012-04-18 13:53:13 +02:00
pnp.txt	…
preempt-locking.txt	…
printk-formats.txt	Documentation: update printk-formats.txt	2011-06-15 21:52:50 -07:00
prio_tree.txt	…
ramoops.txt	pstore/ram: Add ECC support	2012-05-17 08:51:59 -07:00
rbtree.txt	Documentation: Update augmented rbtree documentation	2011-07-24 10:03:05 -07:00
remoteproc.txt	remoteproc: remove the single rpmsg vdev limitation	2012-03-06 19:14:12 +02:00
rfkill.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	rpmsg: add virtio-based remote processor messaging bus	2012-02-08 22:53:58 +02:00
rt-mutex-design.txt	…
rt-mutex.txt	…
rtc.txt	RTC: Fix up rtc.txt documentation to reflect changes to generic rtc layer	2011-03-09 11:25:10 -08:00
serial-console.txt	…
sgi-ioc4.txt	…
sgi-visws.txt	…
sparse.txt	…
spinlocks.txt	Documentation/spinlocks.txt: Remove reference to sti()/cli()	2011-07-11 12:45:04 -07:00
stable_api_nonsense.txt	doc: stable_api_nonsense.txt: fix paragraph to make more sense.	2011-03-30 12:02:05 +02:00
stable_kernel_rules.txt	stable: update documentation to ask for kernel version	2012-01-24 10:50:22 -08:00
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: Crutcher Dunnavant is unavailable	2012-03-30 16:03:15 -07:00
unaligned-memory-access.txt	…
unicode.txt	…
unshare.txt	…
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: Document debugging tricks	2011-03-31 13:40:42 +02:00
xz.txt	decompressors: add XZ decompressor module	2011-01-13 08:03:24 -08:00
zorro.txt	…