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12 years agoMerge remote-tracking branch 'pm/linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:44:27 +0000 (13:44 +1000)]
Merge remote-tracking branch 'pm/linux-next'

12 years agoMerge remote-tracking branch 'trivial/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:38:12 +0000 (13:38 +1000)]
Merge remote-tracking branch 'trivial/for-next'

12 years agoMerge remote-tracking branch 'osd/linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:36:36 +0000 (13:36 +1000)]
Merge remote-tracking branch 'osd/linux-next'

12 years agoMerge remote-tracking branch 'iommu/next'
Stephen Rothwell [Wed, 22 Aug 2012 03:34:58 +0000 (13:34 +1000)]
Merge remote-tracking branch 'iommu/next'

12 years agoMerge remote-tracking branch 'watchdog/master'
Stephen Rothwell [Wed, 22 Aug 2012 03:33:18 +0000 (13:33 +1000)]
Merge remote-tracking branch 'watchdog/master'

12 years agoMerge remote-tracking branch 'selinux/master'
Stephen Rothwell [Wed, 22 Aug 2012 03:33:12 +0000 (13:33 +1000)]
Merge remote-tracking branch 'selinux/master'

12 years agoMerge remote-tracking branch 'security/next'
Stephen Rothwell [Wed, 22 Aug 2012 03:31:07 +0000 (13:31 +1000)]
Merge remote-tracking branch 'security/next'

12 years agoMerge remote-tracking branch 'regulator/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:29:28 +0000 (13:29 +1000)]
Merge remote-tracking branch 'regulator/for-next'

12 years agoMerge remote-tracking branch 'md/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:27:37 +0000 (13:27 +1000)]
Merge remote-tracking branch 'md/for-next'

12 years agoMerge remote-tracking branch 'slab/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:25:58 +0000 (13:25 +1000)]
Merge remote-tracking branch 'slab/for-next'

12 years agoMerge remote-tracking branch 'kgdb/kgdb-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:24:20 +0000 (13:24 +1000)]
Merge remote-tracking branch 'kgdb/kgdb-next'

12 years agoMerge remote-tracking branch 'mmc/mmc-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:22:40 +0000 (13:22 +1000)]
Merge remote-tracking branch 'mmc/mmc-next'

12 years agoMerge branch 'quilt/device-mapper'
Stephen Rothwell [Wed, 22 Aug 2012 03:20:55 +0000 (13:20 +1000)]
Merge branch 'quilt/device-mapper'

12 years agoMerge remote-tracking branch 'block/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:18:28 +0000 (13:18 +1000)]
Merge remote-tracking branch 'block/for-next'

12 years agoMerge remote-tracking branch 'cgroup/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 03:18:26 +0000 (13:18 +1000)]
Merge remote-tracking branch 'cgroup/for-next'

12 years agoMerge remote-tracking branch 'input/next'
Stephen Rothwell [Wed, 22 Aug 2012 03:16:49 +0000 (13:16 +1000)]
Merge remote-tracking branch 'input/next'

12 years agoMerge branch 'quilt/rr'
Stephen Rothwell [Wed, 22 Aug 2012 03:11:22 +0000 (13:11 +1000)]
Merge branch 'quilt/rr'

Conflicts:
arch/alpha/Kconfig
arch/mips/kernel/module.c
arch/s390/Kconfig
arch/xtensa/Kconfig

12 years agoMerge remote-tracking branch 'sound-asoc/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:27:35 +0000 (12:27 +1000)]
Merge remote-tracking branch 'sound-asoc/for-next'

12 years agoMerge remote-tracking branch 'sound/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:25:52 +0000 (12:25 +1000)]
Merge remote-tracking branch 'sound/for-next'

12 years agoMerge remote-tracking branch 'drm/drm-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:25:49 +0000 (12:25 +1000)]
Merge remote-tracking branch 'drm/drm-next'

12 years agoMerge remote-tracking branch 'crypto/master'
Stephen Rothwell [Wed, 22 Aug 2012 02:24:07 +0000 (12:24 +1000)]
Merge remote-tracking branch 'crypto/master'

12 years agoMerge remote-tracking branch 'l2-mtd/master'
Stephen Rothwell [Wed, 22 Aug 2012 02:22:32 +0000 (12:22 +1000)]
Merge remote-tracking branch 'l2-mtd/master'

12 years agoMerge remote-tracking branch 'mtd/master'
Stephen Rothwell [Wed, 22 Aug 2012 02:20:53 +0000 (12:20 +1000)]
Merge remote-tracking branch 'mtd/master'

12 years agoMerge remote-tracking branch 'bluetooth/master'
Stephen Rothwell [Wed, 22 Aug 2012 02:19:16 +0000 (12:19 +1000)]
Merge remote-tracking branch 'bluetooth/master'

12 years agoMerge remote-tracking branch 'wireless-next/master'
Stephen Rothwell [Wed, 22 Aug 2012 02:17:22 +0000 (12:17 +1000)]
Merge remote-tracking branch 'wireless-next/master'

12 years agoMerge remote-tracking branch 'net-next/master'
Stephen Rothwell [Wed, 22 Aug 2012 02:10:17 +0000 (12:10 +1000)]
Merge remote-tracking branch 'net-next/master'

12 years agoMerge remote-tracking branch 'slave-dma/next'
Stephen Rothwell [Wed, 22 Aug 2012 02:08:40 +0000 (12:08 +1000)]
Merge remote-tracking branch 'slave-dma/next'

12 years agoMerge remote-tracking branch 'target-updates/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:06:59 +0000 (12:06 +1000)]
Merge remote-tracking branch 'target-updates/for-next'

12 years agoMerge remote-tracking branch 'scsi/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:05:17 +0000 (12:05 +1000)]
Merge remote-tracking branch 'scsi/for-next'

Conflicts:
drivers/ata/libata-core.c

12 years agoMerge remote-tracking branch 'dlm/next'
Stephen Rothwell [Wed, 22 Aug 2012 02:03:41 +0000 (12:03 +1000)]
Merge remote-tracking branch 'dlm/next'

12 years agoMerge remote-tracking branch 'ubi/linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:02:02 +0000 (12:02 +1000)]
Merge remote-tracking branch 'ubi/linux-next'

12 years agoMerge remote-tracking branch 'thermal/next'
Stephen Rothwell [Wed, 22 Aug 2012 02:00:27 +0000 (12:00 +1000)]
Merge remote-tracking branch 'thermal/next'

12 years agoMerge remote-tracking branch 'cpuidle/cpuidle-next'
Stephen Rothwell [Wed, 22 Aug 2012 02:00:20 +0000 (12:00 +1000)]
Merge remote-tracking branch 'cpuidle/cpuidle-next'

Conflicts:
drivers/cpuidle/coupled.c

12 years agoMerge remote-tracking branch 'libata/NEXT'
Stephen Rothwell [Wed, 22 Aug 2012 01:58:37 +0000 (11:58 +1000)]
Merge remote-tracking branch 'libata/NEXT'

12 years agoMerge remote-tracking branch 'kconfig/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:56:59 +0000 (11:56 +1000)]
Merge remote-tracking branch 'kconfig/for-next'

12 years agoMerge remote-tracking branch 'kbuild/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:56:49 +0000 (11:56 +1000)]
Merge remote-tracking branch 'kbuild/for-next'

12 years agoMerge remote-tracking branch 'v4l-dvb/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:54:55 +0000 (11:54 +1000)]
Merge remote-tracking branch 'v4l-dvb/master'

12 years agoMerge remote-tracking branch 'hwmon-staging/hwmon-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:53:29 +0000 (11:53 +1000)]
Merge remote-tracking branch 'hwmon-staging/hwmon-next'

12 years agoMerge branch 'quilt/jdelvare-hwmon'
Stephen Rothwell [Wed, 22 Aug 2012 01:51:59 +0000 (11:51 +1000)]
Merge branch 'quilt/jdelvare-hwmon'

12 years agoMerge remote-tracking branch 'i2c-embedded/i2c-embedded/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:50:34 +0000 (11:50 +1000)]
Merge remote-tracking branch 'i2c-embedded/i2c-embedded/for-next'

12 years agoMerge branch 'quilt/i2c'
Stephen Rothwell [Wed, 22 Aug 2012 01:49:03 +0000 (11:49 +1000)]
Merge branch 'quilt/i2c'

12 years agoMerge remote-tracking branch 'hid/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:47:33 +0000 (11:47 +1000)]
Merge remote-tracking branch 'hid/for-next'

12 years agoMerge remote-tracking branch 'vfs/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:40:36 +0000 (11:40 +1000)]
Merge remote-tracking branch 'vfs/for-next'

12 years agoMerge remote-tracking branch 'xfs/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:39:00 +0000 (11:39 +1000)]
Merge remote-tracking branch 'xfs/for-next'

12 years agoMerge remote-tracking branch 'ubifs/linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:37:33 +0000 (11:37 +1000)]
Merge remote-tracking branch 'ubifs/linux-next'

12 years agoMerge remote-tracking branch 'ocfs2/linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:35:57 +0000 (11:35 +1000)]
Merge remote-tracking branch 'ocfs2/linux-next'

12 years agoMerge remote-tracking branch 'nfs/linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:34:24 +0000 (11:34 +1000)]
Merge remote-tracking branch 'nfs/linux-next'

12 years agoMerge remote-tracking branch 'logfs/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:32:55 +0000 (11:32 +1000)]
Merge remote-tracking branch 'logfs/master'

12 years agoMerge remote-tracking branch 'gfs2/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:31:26 +0000 (11:31 +1000)]
Merge remote-tracking branch 'gfs2/master'

12 years agoMerge remote-tracking branch 'ext4/dev'
Stephen Rothwell [Wed, 22 Aug 2012 01:29:56 +0000 (11:29 +1000)]
Merge remote-tracking branch 'ext4/dev'

12 years agoMerge remote-tracking branch 'ext3/for_next'
Stephen Rothwell [Wed, 22 Aug 2012 01:28:30 +0000 (11:28 +1000)]
Merge remote-tracking branch 'ext3/for_next'

12 years agoMerge remote-tracking branch 'cifs/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:27:01 +0000 (11:27 +1000)]
Merge remote-tracking branch 'cifs/for-next'

12 years agoMerge remote-tracking branch 'xtensa/for_next'
Stephen Rothwell [Wed, 22 Aug 2012 01:25:34 +0000 (11:25 +1000)]
Merge remote-tracking branch 'xtensa/for_next'

12 years agoMerge remote-tracking branch 'unicore32/unicore32'
Stephen Rothwell [Wed, 22 Aug 2012 01:24:09 +0000 (11:24 +1000)]
Merge remote-tracking branch 'unicore32/unicore32'

12 years agoMerge remote-tracking branch 'sparc-next/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:22:40 +0000 (11:22 +1000)]
Merge remote-tracking branch 'sparc-next/master'

12 years agoMerge remote-tracking branch 'sh/sh-latest'
Stephen Rothwell [Wed, 22 Aug 2012 01:21:11 +0000 (11:21 +1000)]
Merge remote-tracking branch 'sh/sh-latest'

12 years agoMerge remote-tracking branch 's390/features'
Stephen Rothwell [Wed, 22 Aug 2012 01:19:47 +0000 (11:19 +1000)]
Merge remote-tracking branch 's390/features'

12 years agoMerge remote-tracking branch 'galak/next'
Stephen Rothwell [Wed, 22 Aug 2012 01:17:19 +0000 (11:17 +1000)]
Merge remote-tracking branch 'galak/next'

12 years agoMerge remote-tracking branch 'mpc5xxx/next'
Stephen Rothwell [Wed, 22 Aug 2012 01:15:51 +0000 (11:15 +1000)]
Merge remote-tracking branch 'mpc5xxx/next'

12 years agoMerge remote-tracking branch 'parisc/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:14:24 +0000 (11:14 +1000)]
Merge remote-tracking branch 'parisc/for-next'

12 years agoMerge remote-tracking branch 'mips/mips-for-linux-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:12:51 +0000 (11:12 +1000)]
Merge remote-tracking branch 'mips/mips-for-linux-next'

12 years agoMerge remote-tracking branch 'm68knommu/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:11:25 +0000 (11:11 +1000)]
Merge remote-tracking branch 'm68knommu/for-next'

12 years agoMerge remote-tracking branch 'm68k/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:09:52 +0000 (11:09 +1000)]
Merge remote-tracking branch 'm68k/for-next'

12 years agoMerge remote-tracking branch 'cris/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:08:24 +0000 (11:08 +1000)]
Merge remote-tracking branch 'cris/for-next'

12 years agoMerge remote-tracking branch 'arm-perf/for-next/perf'
Stephen Rothwell [Wed, 22 Aug 2012 01:06:55 +0000 (11:06 +1000)]
Merge remote-tracking branch 'arm-perf/for-next/perf'

12 years agoMerge remote-tracking branch 'arm/for-next'
Stephen Rothwell [Wed, 22 Aug 2012 01:05:28 +0000 (11:05 +1000)]
Merge remote-tracking branch 'arm/for-next'

12 years agoMerge remote-tracking branch 'spi-current/spi/merge'
Stephen Rothwell [Wed, 22 Aug 2012 01:03:53 +0000 (11:03 +1000)]
Merge remote-tracking branch 'spi-current/spi/merge'

12 years agoMerge remote-tracking branch 'devicetree-current/devicetree/merge'
Stephen Rothwell [Wed, 22 Aug 2012 01:03:52 +0000 (11:03 +1000)]
Merge remote-tracking branch 'devicetree-current/devicetree/merge'

12 years agoMerge remote-tracking branch 'ide/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:03:45 +0000 (11:03 +1000)]
Merge remote-tracking branch 'ide/master'

12 years agoMerge remote-tracking branch 'crypto-current/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:03:44 +0000 (11:03 +1000)]
Merge remote-tracking branch 'crypto-current/master'

12 years agoMerge remote-tracking branch 'wireless/master'
Stephen Rothwell [Wed, 22 Aug 2012 01:03:40 +0000 (11:03 +1000)]
Merge remote-tracking branch 'wireless/master'

12 years agoMerge remote-tracking branch 'pci-current/for-linus'
Stephen Rothwell [Wed, 22 Aug 2012 01:03:39 +0000 (11:03 +1000)]
Merge remote-tracking branch 'pci-current/for-linus'

12 years agovirtio-blk: Add REQ_FLUSH and REQ_FUA support to bio path
Asias He [Wed, 8 Aug 2012 08:07:05 +0000 (16:07 +0800)]
virtio-blk: Add REQ_FLUSH and REQ_FUA support to bio path

We need to support both REQ_FLUSH and REQ_FUA for bio based path since
it does not get the sequencing of REQ_FUA into REQ_FLUSH that request
based drivers can request.

REQ_FLUSH is emulated by:
A) If the bio has no data to write:
1. Send VIRTIO_BLK_T_FLUSH to device,
2. In the flush I/O completion handler, finish the bio

B) If the bio has data to write:
1. Send VIRTIO_BLK_T_FLUSH to device
2. In the flush I/O completion handler, send the actual write data to device
3. In the write I/O completion handler, finish the bio

REQ_FUA is emulated by:
1. Send the actual write data to device
2. In the write I/O completion handler, send VIRTIO_BLK_T_FLUSH to device
3. In the flush I/O completion handler, finish the bio

Changes in v7:
- Using vbr->flags to trace request type
- Dropped unnecessary struct virtio_blk *vblk parameter
- Reuse struct virtblk_req in bio done function

Cahnges in v6:
- Reworked REQ_FLUSH and REQ_FUA emulatation order

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agovirtio-blk: Add bio-based IO path for virtio-blk
Asias He [Wed, 8 Aug 2012 08:07:04 +0000 (16:07 +0800)]
virtio-blk: Add bio-based IO path for virtio-blk

This patch introduces bio-based IO path for virtio-blk.

Compared to request-based IO path, bio-based IO path uses driver
provided ->make_request_fn() method to bypasses the IO scheduler. It
handles the bio to device directly without allocating a request in block
layer. This reduces the IO path in guest kernel to achieve high IOPS
and lower latency. The downside is that guest can not use the IO
scheduler to merge and sort requests. However, this is not a big problem
if the backend disk in host side uses faster disk device.

When the bio-based IO path is not enabled, virtio-blk still uses the
original request-based IO path, no performance difference is observed.

Using a slow device e.g. normal SATA disk, the bio-based IO path for
sequential read and write are slower than req-based IO path due to lack
of merge in guest kernel. So we make the bio-based path optional.

Performance evaluation:
-----------------------------
1) Fio test is performed in a 8 vcpu guest with ramdisk based guest using
kvm tool.

Short version:
 With bio-based IO path, sequential read/write, random read/write
 IOPS boost         : 28%, 24%, 21%, 16%
 Latency improvement: 32%, 17%, 21%, 16%

Long version:
 With bio-based IO path:
  seq-read  : io=2048.0MB, bw=116996KB/s, iops=233991 , runt= 17925msec
  seq-write : io=2048.0MB, bw=100829KB/s, iops=201658 , runt= 20799msec
  rand-read : io=3095.7MB, bw=112134KB/s, iops=224268 , runt= 28269msec
  rand-write: io=3095.7MB, bw=96198KB/s,  iops=192396 , runt= 32952msec
    clat (usec): min=0 , max=2631.6K, avg=58716.99, stdev=191377.30
    clat (usec): min=0 , max=1753.2K, avg=66423.25, stdev=81774.35
    clat (usec): min=0 , max=2915.5K, avg=61685.70, stdev=120598.39
    clat (usec): min=0 , max=1933.4K, avg=76935.12, stdev=96603.45
  cpu : usr=74.08%, sys=703.84%, ctx=29661403, majf=21354, minf=22460954
  cpu : usr=70.92%, sys=702.81%, ctx=77219828, majf=13980, minf=27713137
  cpu : usr=72.23%, sys=695.37%, ctx=88081059, majf=18475, minf=28177648
  cpu : usr=69.69%, sys=654.13%, ctx=145476035, majf=15867, minf=26176375
 With request-based IO path:
  seq-read  : io=2048.0MB, bw=91074KB/s, iops=182147 , runt= 23027msec
  seq-write : io=2048.0MB, bw=80725KB/s, iops=161449 , runt= 25979msec
  rand-read : io=3095.7MB, bw=92106KB/s, iops=184211 , runt= 34416msec
  rand-write: io=3095.7MB, bw=82815KB/s, iops=165630 , runt= 38277msec
    clat (usec): min=0 , max=1932.4K, avg=77824.17, stdev=170339.49
    clat (usec): min=0 , max=2510.2K, avg=78023.96, stdev=146949.15
    clat (usec): min=0 , max=3037.2K, avg=74746.53, stdev=128498.27
    clat (usec): min=0 , max=1363.4K, avg=89830.75, stdev=114279.68
  cpu : usr=53.28%, sys=724.19%, ctx=37988895, majf=17531, minf=23577622
  cpu : usr=49.03%, sys=633.20%, ctx=205935380, majf=18197, minf=27288959
  cpu : usr=55.78%, sys=722.40%, ctx=101525058, majf=19273, minf=28067082
  cpu : usr=56.55%, sys=690.83%, ctx=228205022, majf=18039, minf=26551985

2) Fio test is performed in a 8 vcpu guest with Fusion-IO based guest using
kvm tool.

Short version:
 With bio-based IO path, sequential read/write, random read/write
 IOPS boost         : 11%, 11%, 13%, 10%
 Latency improvement: 10%, 10%, 12%, 10%
Long Version:
 With bio-based IO path:
  read : io=2048.0MB, bw=58920KB/s, iops=117840 , runt= 35593msec
  write: io=2048.0MB, bw=64308KB/s, iops=128616 , runt= 32611msec
  read : io=3095.7MB, bw=59633KB/s, iops=119266 , runt= 53157msec
  write: io=3095.7MB, bw=62993KB/s, iops=125985 , runt= 50322msec
    clat (usec): min=0 , max=1284.3K, avg=128109.01, stdev=71513.29
    clat (usec): min=94 , max=962339 , avg=116832.95, stdev=65836.80
    clat (usec): min=0 , max=1846.6K, avg=128509.99, stdev=89575.07
    clat (usec): min=0 , max=2256.4K, avg=121361.84, stdev=82747.25
  cpu : usr=56.79%, sys=421.70%, ctx=147335118, majf=21080, minf=19852517
  cpu : usr=61.81%, sys=455.53%, ctx=143269950, majf=16027, minf=24800604
  cpu : usr=63.10%, sys=455.38%, ctx=178373538, majf=16958, minf=24822612
  cpu : usr=62.04%, sys=453.58%, ctx=226902362, majf=16089, minf=23278105
 With request-based IO path:
  read : io=2048.0MB, bw=52896KB/s, iops=105791 , runt= 39647msec
  write: io=2048.0MB, bw=57856KB/s, iops=115711 , runt= 36248msec
  read : io=3095.7MB, bw=52387KB/s, iops=104773 , runt= 60510msec
  write: io=3095.7MB, bw=57310KB/s, iops=114619 , runt= 55312msec
    clat (usec): min=0 , max=1532.6K, avg=142085.62, stdev=109196.84
    clat (usec): min=0 , max=1487.4K, avg=129110.71, stdev=114973.64
    clat (usec): min=0 , max=1388.6K, avg=145049.22, stdev=107232.55
    clat (usec): min=0 , max=1465.9K, avg=133585.67, stdev=110322.95
  cpu : usr=44.08%, sys=590.71%, ctx=451812322, majf=14841, minf=17648641
  cpu : usr=48.73%, sys=610.78%, ctx=418953997, majf=22164, minf=26850689
  cpu : usr=45.58%, sys=581.16%, ctx=714079216, majf=21497, minf=22558223
  cpu : usr=48.40%, sys=599.65%, ctx=656089423, majf=16393, minf=23824409

3) Fio test is performed in a 8 vcpu guest with normal SATA based guest
using kvm tool.

Short version:
 With bio-based IO path, sequential read/write, random read/write
 IOPS boost         : -10%, -10%, 4.4%, 0.5%
 Latency improvement: -12%, -15%, 2.5%, 0.8%
Long Version:
 With bio-based IO path:
  read : io=124812KB, bw=36537KB/s, iops=9060 , runt=  3416msec
  write: io=169180KB, bw=24406KB/s, iops=6065 , runt=  6932msec
  read : io=256200KB, bw=2089.3KB/s, iops=520 , runt=122630msec
  write: io=257988KB, bw=1545.7KB/s, iops=384 , runt=166910msec
    clat (msec): min=1 , max=1527 , avg=28.06, stdev=89.54
    clat (msec): min=2 , max=344 , avg=41.12, stdev=38.70
    clat (msec): min=8 , max=1984 , avg=490.63, stdev=207.28
    clat (msec): min=33 , max=4131 , avg=659.19, stdev=304.71
  cpu          : usr=4.85%, sys=17.15%, ctx=31593, majf=0, minf=7
  cpu          : usr=3.04%, sys=11.45%, ctx=39377, majf=0, minf=0
  cpu          : usr=0.47%, sys=1.59%, ctx=262986, majf=0, minf=16
  cpu          : usr=0.47%, sys=1.46%, ctx=337410, majf=0, minf=0

 With request-based IO path:
  read : io=150120KB, bw=40420KB/s, iops=10037 , runt=  3714msec
  write: io=194932KB, bw=27029KB/s, iops=6722 , runt=  7212msec
  read : io=257136KB, bw=2001.1KB/s, iops=498 , runt=128443msec
  write: io=258276KB, bw=1537.2KB/s, iops=382 , runt=168028msec
    clat (msec): min=1 , max=1542 , avg=24.84, stdev=32.45
    clat (msec): min=3 , max=628 , avg=35.62, stdev=39.71
    clat (msec): min=8 , max=2540 , avg=503.28, stdev=236.97
    clat (msec): min=41 , max=4398 , avg=653.88, stdev=302.61
  cpu          : usr=3.91%, sys=15.75%, ctx=26968, majf=0, minf=23
  cpu          : usr=2.50%, sys=10.56%, ctx=19090, majf=0, minf=0
  cpu          : usr=0.16%, sys=0.43%, ctx=20159, majf=0, minf=16
  cpu          : usr=0.18%, sys=0.53%, ctx=81364, majf=0, minf=0

How to use:
-----------------------------
Add 'virtio_blk.use_bio=1' to kernel cmdline or 'modprobe virtio_blk
use_bio=1' to enable ->make_request_fn() based I/O path.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Asias He <asias@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agoblock: Add blk_bio_map_sg() helper
Asias He [Thu, 2 Aug 2012 21:42:04 +0000 (23:42 +0200)]
block: Add blk_bio_map_sg() helper

Add a helper to map a bio to a scatterlist, modelled after
blk_rq_map_sg.

This helper is useful for any driver that wants to create
a scatterlist from its ->make_request_fn method.

Changes in v2:
 - Use __blk_segment_map_sg to avoid duplicated code
 - Add cocbook style function comment

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agoblock: Introduce __blk_segment_map_sg() helper
Asias He [Thu, 2 Aug 2012 21:42:03 +0000 (23:42 +0200)]
block: Introduce __blk_segment_map_sg() helper

Split the mapping code in blk_rq_map_sg() to a helper
__blk_segment_map_sg(), so that other mapping function, e.g.
blk_bio_map_sg(), can share the code.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Suggested-by: Jens Axboe <axboe@kernel.dk>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agotools: Add guest trace agent as a user tool
Yoshihiro YUNOMAE [Thu, 9 Aug 2012 12:31:30 +0000 (21:31 +0900)]
tools: Add guest trace agent as a user tool

This patch adds a user tool, "trace agent" for sending trace data of a guest to
a Host in low overhead. This agent has the following functions:
 - splice a page of ring-buffer to read_pipe without memory copying
 - splice the page from write_pipe to virtio-console without memory copying
 - write trace data to stdout by using -o option
 - controlled by start/stop orders from a Host

Changes in v2:
 - Cleanup (change fprintf() to pr_err() and an include guard)

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agovirtio/console: Allocate scatterlist according to the current pipe size
Masami Hiramatsu [Thu, 9 Aug 2012 12:31:20 +0000 (21:31 +0900)]
virtio/console: Allocate scatterlist according to the current pipe size

Allocate scatterlist according to the current pipe size.
This allows splicing bigger buffer if the pipe size has
been changed by fcntl.

Changes in v2:
 - Just a minor fix for avoiding a confliction with previous patch.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agoftrace: Allow stealing pages from pipe buffer
Masami Hiramatsu [Thu, 9 Aug 2012 12:31:10 +0000 (21:31 +0900)]
ftrace: Allow stealing pages from pipe buffer

Use generic steal operation on pipe buffer to allow stealing
ring buffer's read page from pipe buffer.

Note that this could reduce the performance of splice on the
splice_write side operation without affinity setting.
Since the ring buffer's read pages are allocated on the
tracing-node, but the splice user does not always execute
splice write side operation on the same node. In this case,
the page will be accessed from the another node.
Thus, it is strongly recommended to assign the splicing
thread to corresponding node.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agovirtio/console: Wait until the port is ready on splice
Masami Hiramatsu [Thu, 9 Aug 2012 12:31:00 +0000 (21:31 +0900)]
virtio/console: Wait until the port is ready on splice

Wait if the port is not connected or full on splice
like as write is doing.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agovirtio/console: Add a failback for unstealable pipe buffer
Masami Hiramatsu [Thu, 9 Aug 2012 12:30:50 +0000 (21:30 +0900)]
virtio/console: Add a failback for unstealable pipe buffer

Add a failback memcpy path for unstealable pipe buffer.
If buf->ops->steal() fails, virtio-serial tries to
copy the page contents to an allocated page, instead
of just failing splice().

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agovirtio/console: Add splice_write support
Masami Hiramatsu [Thu, 9 Aug 2012 12:30:39 +0000 (21:30 +0900)]
virtio/console: Add splice_write support

Enable to use splice_write from pipe to virtio-console port.
This steals pages from pipe and directly send it to host.

Note that this may accelerate only the guest to host path.

Changes in v2:
 - Use GFP_KERNEL instead of GFP_ATOMIC in syscall context function.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agoMake most arch asm/module.h files use asm-generic/module.h
David Howells [Wed, 22 Aug 2012 00:47:10 +0000 (10:47 +1000)]
Make most arch asm/module.h files use asm-generic/module.h

Use the mapping of Elf_[SPE]hdr, Elf_Addr, Elf_Sym, Elf_Dyn, Elf_Rel/Rela,
ELF_R_TYPE() and ELF_R_SYM() to either the 32-bit version or the 64-bit version
into asm-generic/module.h for all arches bar MIPS.

Also, use the generic definition mod_arch_specific where possible.

To this end, I've defined three new config bools:

 (*) HAVE_MOD_ARCH_SPECIFIC

     Arches define this if they don't want to use the empty generic
     mod_arch_specific struct.

 (*) MODULES_USE_ELF_RELA

     Arches define this if their modules can contain RELA records.  This causes
     the Elf_Rela mapping to be emitted and allows apply_relocate_add() to be
     defined by the arch rather than have the core emit an error message.

 (*) MODULES_USE_ELF_REL

     Arches define this if their modules can contain REL records.  This causes
     the Elf_Rel mapping to be emitted and allows apply_relocate() to be
     defined by the arch rather than have the core emit an error message.

Note that it is possible to allow both REL and RELA records: m68k and mips are
two arches that do this.

With this, some arch asm/module.h files can be deleted entirely and replaced
with a generic-y marker in the arch Kbuild file.

Additionally, I have removed the bits from m32r and score that handle the
unsupported type of relocation record as that's now handled centrally.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agoMIPS: Fix module.c build for 32 bit
Ralf Baechle [Tue, 14 Aug 2012 15:13:45 +0000 (17:13 +0200)]
MIPS: Fix module.c build for 32 bit

Fixes build failure introduced by "Make most arch asm/module.h files use
asm-generic/module.h" by moving all the RELA processing code to a
separate file to be used only for RELA processing on 64-bit kernels.

  CC      arch/mips/kernel/module.o
arch/mips/kernel/module.c:250:14: error: 'reloc_handlers_rela' defined but not
used [-Werror=unused-variable]
cc1: all warnings being treated as errors

make[6]: *** [arch/mips/kernel/module.o] Error 1

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
12 years agomodule: taint kernel when lve module is loaded
Matthew Garrett [Fri, 22 Jun 2012 17:49:31 +0000 (13:49 -0400)]
module: taint kernel when lve module is loaded

Cloudlinux have a product called lve that includes a kernel module. This
was previously GPLed but is now under a proprietary license, but the
module continues to declare MODULE_LICENSE("GPL") and makes use of some
EXPORT_SYMBOL_GPL symbols. Forcibly taint it in order to avoid this.

Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Alex Lyashkov <umka@cloudlinux.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
12 years agoMerge branch 'akpm' (Andrew's patch-bomb)
Linus Torvalds [Wed, 22 Aug 2012 00:22:22 +0000 (17:22 -0700)]
Merge branch 'akpm' (Andrew's patch-bomb)

Merge fixes from Andrew Morton.

Random drivers and some VM fixes.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (17 commits)
  mm: compaction: Abort async compaction if locks are contended or taking too long
  mm: have order > 0 compaction start near a pageblock with free pages
  rapidio/tsi721: fix unused variable compiler warning
  rapidio/tsi721: fix inbound doorbell interrupt handling
  drivers/rtc/rtc-rs5c348.c: fix hour decoding in 12-hour mode
  mm: correct page->pfmemalloc to fix deactivate_slab regression
  drivers/rtc/rtc-pcf2123.c: initialize dynamic sysfs attributes
  mm/compaction.c: fix deferring compaction mistake
  drivers/misc/sgi-xp/xpc_uv.c: SGI XPC fails to load when cpu 0 is out of IRQ resources
  string: do not export memweight() to userspace
  hugetlb: update hugetlbpage.txt
  checkpatch: add control statement test to SINGLE_STATEMENT_DO_WHILE_MACRO
  mm: hugetlbfs: correctly populate shared pmd
  cciss: fix incorrect scsi status reporting
  Documentation: update mount option in filesystem/vfat.txt
  mm: change nr_ptes BUG_ON to WARN_ON
  cs5535-clockevt: typo, it's MFGPT, not MFPGT

12 years agoMerge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...
Linus Torvalds [Tue, 21 Aug 2012 23:54:38 +0000 (16:54 -0700)]
Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media

Pull media fixes from Mauro Carvalho Chehab:
 "For bug fixes, at soc_camera, si470x, uvcvideo, iguanaworks IR driver,
  radio_shark Kbuild fixes, and at the V4L2 core (radio fixes)."

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  [media] media: soc_camera: don't clear pix->sizeimage in JPEG mode
  [media] media: mx2_camera: Fix clock handling for i.MX27
  [media] video: mx2_camera: Use clk_prepare_enable/clk_disable_unprepare
  [media] video: mx1_camera: Use clk_prepare_enable/clk_disable_unprepare
  [media] media: mx3_camera: buf_init() add buffer state check
  [media] radio-shark2: Only compile led support when CONFIG_LED_CLASS is set
  [media] radio-shark: Only compile led support when CONFIG_LED_CLASS is set
  [media] radio-shark*: Call cancel_work_sync from disconnect rather then release
  [media] radio-shark*: Remove work-around for dangling pointer in usb intfdata
  [media] Add USB dependency for IguanaWorks USB IR Transceiver
  [media] Add missing logging for rangelow/high of hwseek
  [media] VIDIOC_ENUM_FREQ_BANDS fix
  [media] mem2mem_testdev: fix querycap regression
  [media] si470x: v4l2-compliance fixes
  [media] DocBook: Remove a spurious character
  [media] uvcvideo: Reset the bytesused field when recycling an erroneous buffer

12 years agoMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Linus Torvalds [Tue, 21 Aug 2012 23:46:08 +0000 (16:46 -0700)]
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Pull networking update from David Miller:
 "A couple weeks of bug fixing in there.  The largest chunk is all the
  broken crap Amerigo Wang found in the netpoll layer."

 1) netpoll and it's users has several serious bugs:
    a) uses GFP_KERNEL with locks held
    b) interfaces requiring interrupts disabled are called with them
       enabled
    c) and vice versa
    d) VLAN tag demuxing, as per all other RX packet input paths, is not
       applied

    All from Amerigo Wang.

 2) Hopefully cure the ipv4 mapped ipv6 address TCP early demux bugs for
    good, from Neal Cardwell.

 3) Unlike AF_UNIX, AF_PACKET sockets don't set a default credentials
    when the user doesn't specify one explicitly during sendmsg().
    Instead we attach an empty (zero) SCM credential block which is
    definitely not what we want.  Fix from Eric Dumazet.

 4) IPv6 illegally invokes netdevice notifiers with RCU lock held, fix
    from Ben Hutchings.

 5) inet_csk_route_child_sock() checks wrong inet options pointer, fix
    from Christoph Paasch.

 6) When AF_PACKET is used for transmit, packet loopback doesn't behave
    properly when a socket fanout is enabled, from Eric Leblond.

 7) On bluetooth l2cap channel create failure, we leak the socket, from
    Jaganath Kanakkassery.

 8) Fix all the netprio file handling bugs found by Al Viro, from John
    Fastabend.

 9) Several error return and NULL deref bug fixes in networking drivers
    from Julia Lawall.

10) A large smattering of struct padding et al.  kernel memory leaks to
    userspace found of Mathias Krause.

11) Conntrack expections in netfilter can access an uninitialized timer,
    fix from Pablo Neira Ayuso.

12) Several netfilter SIP tracker bug fixes from Patrick McHardy.

13) IPSEC ipv6 routes are not initialized correctly all the time,
    resulting in an OOPS in inet_putpeer().  Also from Patrick McHardy.

14) Bridging does rcu_dereference() outside of RCU protected area, from
    Stephen Hemminger.

15) Fix routing cache removal performance regression when looking up
    output routes that have a local destination.  From Zheng Yan.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (87 commits)
  af_netlink: force credentials passing [CVE-2012-3520]
  ipv4: fix ip header ident selection in __ip_make_skb()
  ipv4: Use newinet->inet_opt in inet_csk_route_child_sock()
  tcp: fix possible socket refcount problem
  net: tcp: move sk_rx_dst_set call after tcp_create_openreq_child()
  net/core/dev.c: fix kernel-doc warning
  netconsole: remove a redundant netconsole_target_put()
  net: ipv6: fix oops in inet_putpeer()
  net/stmmac: fix issue of clk_get for Loongson1B.
  caif: Do not dereference NULL in chnl_recv_cb()
  af_packet: don't emit packet on orig fanout group
  drivers/net/irda: fix error return code
  drivers/net/wan/dscc4.c: fix error return code
  drivers/net/wimax/i2400m/fw.c: fix error return code
  smsc75xx: add missing entry to MAINTAINERS
  net: qmi_wwan: new devices: UML290 and K5006-Z
  net: sh_eth: Add eth support for R8A7779 device
  netdev/phy: skip disabled mdio-mux nodes
  dt: introduce for_each_available_child_of_node, of_get_next_available_child
  net: netprio: fix cgrp create and write priomap race
  ...

12 years agomm: compaction: Abort async compaction if locks are contended or taking too long
Mel Gorman [Tue, 21 Aug 2012 23:16:17 +0000 (16:16 -0700)]
mm: compaction: Abort async compaction if locks are contended or taking too long

Jim Schutt reported a problem that pointed at compaction contending
heavily on locks.  The workload is straight-forward and in his own words;

The systems in question have 24 SAS drives spread across 3 HBAs,
running 24 Ceph OSD instances, one per drive.  FWIW these servers
are dual-socket Intel 5675 Xeons w/48 GB memory.  I've got ~160
Ceph Linux clients doing dd simultaneously to a Ceph file system
backed by 12 of these servers.

Early in the test everything looks fine

  procs -------------------memory------------------ ---swap-- -----io---- --system-- -----cpu-------
   r  b       swpd       free       buff      cache   si   so    bi    bo   in   cs  us sy  id wa st
  31 15          0     287216        576   38606628    0    0     2  1158    2   14   1  3  95  0  0
  27 15          0     225288        576   38583384    0    0    18 2222016 203357 134876  11 56  17 15  0
  28 17          0     219256        576   38544736    0    0    11 2305932 203141 146296  11 49  23 17  0
   6 18          0     215596        576   38552872    0    0     7 2363207 215264 166502  12 45  22 20  0
  22 18          0     226984        576   38596404    0    0     3 2445741 223114 179527  12 43  23 22  0

and then it goes to pot

  procs -------------------memory------------------ ---swap-- -----io---- --system-- -----cpu-------
   r  b       swpd       free       buff      cache   si   so    bi    bo   in   cs  us sy  id wa st
  163  8          0     464308        576   36791368    0    0    11 22210  866  536   3 13  79  4  0
  207 14          0     917752        576   36181928    0    0   712 1345376 134598 47367   7 90   1  2  0
  123 12          0     685516        576   36296148    0    0   429 1386615 158494 60077   8 84   5  3  0
  123 12          0     598572        576   36333728    0    0  1107 1233281 147542 62351   7 84   5  4  0
  622  7          0     660768        576   36118264    0    0   557 1345548 151394 59353   7 85   4  3  0
  223 11          0     283960        576   36463868    0    0    46 1107160 121846 33006   6 93   1  1  0

Note that system CPU usage is very high blocks being written out has
dropped by 42%. He analysed this with perf and found

  perf record -g -a sleep 10
  perf report --sort symbol --call-graph fractal,5
    34.63%  [k] _raw_spin_lock_irqsave
            |
            |--97.30%-- isolate_freepages
            |          compaction_alloc
            |          unmap_and_move
            |          migrate_pages
            |          compact_zone
            |          compact_zone_order
            |          try_to_compact_pages
            |          __alloc_pages_direct_compact
            |          __alloc_pages_slowpath
            |          __alloc_pages_nodemask
            |          alloc_pages_vma
            |          do_huge_pmd_anonymous_page
            |          handle_mm_fault
            |          do_page_fault
            |          page_fault
            |          |
            |          |--87.39%-- skb_copy_datagram_iovec
            |          |          tcp_recvmsg
            |          |          inet_recvmsg
            |          |          sock_recvmsg
            |          |          sys_recvfrom
            |          |          system_call
            |          |          __recv
            |          |          |
            |          |           --100.00%-- (nil)
            |          |
            |           --12.61%-- memcpy
             --2.70%-- [...]

There was other data but primarily it is all showing that compaction is
contended heavily on the zone->lock and zone->lru_lock.

commit [b2eef8c0: mm: compaction: minimise the time IRQs are disabled
while isolating pages for migration] noted that it was possible for
migration to hold the lru_lock for an excessive amount of time. Very
broadly speaking this patch expands the concept.

This patch introduces compact_checklock_irqsave() to check if a lock
is contended or the process needs to be scheduled. If either condition
is true then async compaction is aborted and the caller is informed.
The page allocator will fail a THP allocation if compaction failed due
to contention. This patch also introduces compact_trylock_irqsave()
which will acquire the lock only if it is not contended and the process
does not need to schedule.

Reported-by: Jim Schutt <jaschut@sandia.gov>
Tested-by: Jim Schutt <jaschut@sandia.gov>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agomm: have order > 0 compaction start near a pageblock with free pages
Mel Gorman [Tue, 21 Aug 2012 23:16:15 +0000 (16:16 -0700)]
mm: have order > 0 compaction start near a pageblock with free pages

Commit 7db8889ab05b ("mm: have order > 0 compaction start off where it
left") introduced a caching mechanism to reduce the amount work the free
page scanner does in compaction.  However, it has a problem.  Consider
two process simultaneously scanning free pages

     C
Process A M     S      F
|---------------------------------------|
Process B M  FS

C is zone->compact_cached_free_pfn
S is cc->start_pfree_pfn
M is cc->migrate_pfn
F is cc->free_pfn

In this diagram, Process A has just reached its migrate scanner, wrapped
around and updated compact_cached_free_pfn accordingly.

Simultaneously, Process B finishes isolating in a block and updates
compact_cached_free_pfn again to the location of its free scanner.

Process A moves to "end_of_zone - one_pageblock" and runs this check

                if (cc->order > 0 && (!cc->wrapped ||
                                      zone->compact_cached_free_pfn >
                                      cc->start_free_pfn))
                        pfn = min(pfn, zone->compact_cached_free_pfn);

compact_cached_free_pfn is above where it started so the free scanner
skips almost the entire space it should have scanned.  When there are
multiple processes compacting it can end in a situation where the entire
zone is not being scanned at all.  Further, it is possible for two
processes to ping-pong update to compact_cached_free_pfn which is just
random.

Overall, the end result wrecks allocation success rates.

There is not an obvious way around this problem without introducing new
locking and state so this patch takes a different approach.

First, it gets rid of the skip logic because it's not clear that it
matters if two free scanners happen to be in the same block but with
racing updates it's too easy for it to skip over blocks it should not.

Second, it updates compact_cached_free_pfn in a more limited set of
circumstances.

If a scanner has wrapped, it updates compact_cached_free_pfn to the end
of the zone. When a wrapped scanner isolates a page, it updates
compact_cached_free_pfn to point to the highest pageblock it
can isolate pages from.

If a scanner has not wrapped when it has finished isolated pages it
checks if compact_cached_free_pfn is pointing to the end of the
zone. If so, the value is updated to point to the highest
pageblock that pages were isolated from. This value will not
be updated again until a free page scanner wraps and resets
compact_cached_free_pfn.

This is not optimal and it can still race but the compact_cached_free_pfn
will be pointing to or very near a pageblock with free pages.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agorapidio/tsi721: fix unused variable compiler warning
Alexandre Bounine [Tue, 21 Aug 2012 23:16:12 +0000 (16:16 -0700)]
rapidio/tsi721: fix unused variable compiler warning

Fix unused variable compiler warning when built with CONFIG_RAPIDIO_DEBUG
option off.

This patch is applicable to kernel versions starting from v3.2

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agorapidio/tsi721: fix inbound doorbell interrupt handling
Alexandre Bounine [Tue, 21 Aug 2012 23:16:11 +0000 (16:16 -0700)]
rapidio/tsi721: fix inbound doorbell interrupt handling

Make sure that there is no doorbell messages left behind due to disabled
interrupts during inbound doorbell processing.

The most common case for this bug is loss of rionet JOIN messages in
systems with three or more rionet participants and MSI or MSI-X enabled.
As result, requests for packet transfers may finish with "destination
unreachable" error message.

This patch is applicable to kernel versions starting from v3.2.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agodrivers/rtc/rtc-rs5c348.c: fix hour decoding in 12-hour mode
Atsushi Nemoto [Tue, 21 Aug 2012 23:16:10 +0000 (16:16 -0700)]
drivers/rtc/rtc-rs5c348.c: fix hour decoding in 12-hour mode

Correct the offset by subtracting 20 from tm_hour before taking the
modulo 12.

[ "Why 20?" I hear you ask. Or at least I did.

  Here's the reason why: RS5C348_BIT_PM is 32, and is - stupidly -
  included in the RS5C348_HOURS_MASK define.  So it's really subtracting
  out that bit to get "hour+12".  But then because it does things modulo
  12, it needs to add the 12 in again afterwards anyway.

  This code is confused.  It would be much clearer if RS5C348_HOURS_MASK
  just didn't include the RS5C348_BIT_PM bit at all, then it wouldn't
  need to do the silly subtract either.

  Whatever. It's all just math, the end result is the same.   - Linus ]

Reported-by: James Nute <newten82@gmail.com>
Tested-by: James Nute <newten82@gmail.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agomm: correct page->pfmemalloc to fix deactivate_slab regression
Alex Shi [Tue, 21 Aug 2012 23:16:08 +0000 (16:16 -0700)]
mm: correct page->pfmemalloc to fix deactivate_slab regression

Commit cfd19c5a9ecf ("mm: only set page->pfmemalloc when
ALLOC_NO_WATERMARKS was used") tried to narrow down page->pfmemalloc
setting, but it missed some places the pfmemalloc should be set.

So, in __slab_alloc, the unalignment pfmemalloc and ALLOC_NO_WATERMARKS
cause incorrect deactivate_slab() on our core2 server:

    64.73%           fio  [kernel.kallsyms]     [k] _raw_spin_lock
                     |
                     --- _raw_spin_lock
                        |
                        |---0.34%-- deactivate_slab
                        |          __slab_alloc
                        |          kmem_cache_alloc
                        |          |

That causes our fio sync write performance to have a 40% regression.

Move the checking in get_page_from_freelist() which resolves this issue.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Sage Weil <sage@inktank.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agodrivers/rtc/rtc-pcf2123.c: initialize dynamic sysfs attributes
Ilya Shchepetkov [Tue, 21 Aug 2012 23:16:06 +0000 (16:16 -0700)]
drivers/rtc/rtc-pcf2123.c: initialize dynamic sysfs attributes

Dynamically allocated sysfs attributes must be initialized using
sysfs_attr_init(), otherwise lockdep complains: BUG: key <address> not in
.data!

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Ilya Shchepetkov <shchepetkov@ispras.ru>
Cc: Chris Verges <chrisv@cyberswitching.com>
Cc: Christian Pellegrin <chripell@fsfe.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agomm/compaction.c: fix deferring compaction mistake
Minchan Kim [Tue, 21 Aug 2012 23:16:03 +0000 (16:16 -0700)]
mm/compaction.c: fix deferring compaction mistake

Commit aff622495c9a ("vmscan: only defer compaction for failed order and
higher") fixed bad deferring policy but made mistake about checking
compact_order_failed in __compact_pgdat().  So it can't update
compact_order_failed with the new order.  This ends up preventing
correct operation of policy deferral.  This patch fixes it.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agodrivers/misc/sgi-xp/xpc_uv.c: SGI XPC fails to load when cpu 0 is out of IRQ resources
Robin Holt [Tue, 21 Aug 2012 23:16:02 +0000 (16:16 -0700)]
drivers/misc/sgi-xp/xpc_uv.c: SGI XPC fails to load when cpu 0 is out of IRQ resources

On many of our larger systems, CPU 0 has had all of its IRQ resources
consumed before XPC loads.  Worst cases on machines with multiple 10
GigE cards and multiple IB cards have depleted the entire first socket
of IRQs.

This patch makes selecting the node upon which IRQs are allocated (as
well as all the other GRU Message Queue structures) specifiable as a
module load param and has a default behavior of searching all nodes/cpus
for an available resources.

[akpm@linux-foundation.org: fix build: include cpu.h and module.h]
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agostring: do not export memweight() to userspace
WANG Cong [Tue, 21 Aug 2012 23:16:00 +0000 (16:16 -0700)]
string: do not export memweight() to userspace

Fix the following warning:

  usr/include/linux/string.h:8: userspace cannot reference function or variable defined in the kernel

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agohugetlb: update hugetlbpage.txt
Zhouping Liu [Tue, 21 Aug 2012 23:15:57 +0000 (16:15 -0700)]
hugetlb: update hugetlbpage.txt

Commit f0f57b2b1488 ("mm: move hugepage test examples to
tools/testing/selftests/vm") moved map_hugetlb.c, hugepage-shm.c and
hugepage-mmap.c tests into tools/testing/selftests/vm/ directory, but it
didn't update hugetlbpage.txt

Signed-off-by: Zhouping Liu <sanweidaying@gmail.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
12 years agocheckpatch: add control statement test to SINGLE_STATEMENT_DO_WHILE_MACRO
Joe Perches [Tue, 21 Aug 2012 23:15:53 +0000 (16:15 -0700)]
checkpatch: add control statement test to SINGLE_STATEMENT_DO_WHILE_MACRO

Commit b13edf7ff2dd ("checkpatch: add checks for do {} while (0) macro
misuses") added a test that is overly simplistic for single statement
macros.

Macros that start with control tests should be enclosed in a do {} while
(0) loop.

Add the necessary control tests to the check.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Tested-by: Franz Schrober <franzschrober@yahoo.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>