readahead: make context readahead more conservative

This helps performance on moderately dense random reads on SSD.

Transaction-Per-Second numbers provided by Taobao:

		QPS	case
		-------------------------------------------------------
		7536	disable context readahead totally
w/ patch:	7129	slower size rampup and start RA on the 3rd read
		6717	slower size rampup
w/o patch:	5581	unmodified context readahead

Before, readahead will be started whenever reading page N+1 when it happen
to read N recently.  After patch, we'll only start readahead when *three*
random reads happen to access pages N, N+1, N+2.  The probability of this
happening is extremely low for pure random reads, unless they are very
dense, which actually deserves some readahead.

Also start with a smaller readahead window.  The impact to interleaved
sequential reads should be small, because for a long run stream, the the
small readahead window rampup phase is negletable.

The context readahead actually benefits clustered random reads on HDD
whose seek cost is pretty high.  However as SSD is increasingly used for
random read workloads it's better for the context readahead to concentrate
on interleaved sequential reads.

Another SSD rand read test from Miao

        # file size:        2GB
        # read IO amount: 625MB
        sysbench --test=fileio          \
                --max-requests=10000    \
                --num-threads=1         \
                --file-num=1            \
                --file-block-size=64K   \
                --file-test-mode=rndrd  \
                --file-fsync-freq=0     \
                --file-fsync-end=off    run

shows the performance of btrfs grows up from 69MB/s to 121MB/s, ext4 from
104MB/s to 121MB/s.

Change-Id: Id53ca3937a4f0b53610a6d1474b201bc7ff3d47d
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Tested-by: Tao Ma <tm@tao.ma>
Tested-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ARM: Use -mcpu=cortex-a15 when targeting MSM Krait CPUs

Enable compiler optimizations specific to the Cortex-A15
processor when targeting MSM Krait CPUs. This is necessary
take advantage of the UDIV/SDIV instructions supported by
these processors. To accomplish this, we need to remove the
-march=armv7-a ISA restriction from the compiler options
because 'cortex-a15' is a superset of 'armv7-a'.

Change-Id: I6215aecc11fb4f77c971de7b84f68649ef234357
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Squash krait retention commits

msm: boards: Enable Krait Retention.
Add SPM sequences to do Krait retention for 8960,8930
and 8064. Also added a new rpmrs level containing the
latencies and power measurements for this new low power
state.

CRs-Fixed: 369864
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
____________________

msm: pm: Update spm retention sequence to support per core retention
On krait revision < 3, power driver is not using full spm sequence and
calling into trustzone as a part of executing krait retention.
Also krait retention is not supported on secondary cores.

krait pass3 is upgraded to use full spm sequence, hence add support
for per core retention and avoid calling into trustzone
while executing retention.

Change-Id: I6a2b3d7c4d0fd5b9a340957b16b940b7a09bbd91
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>

msm: acpuclock-krait: Work-around retention corner-case

The CPU clock source MUXes cannot switch while a CPU is in
retention, but callers of acpuclock APIs may not known that
the CPU is in retention.

Work around this problem be always performing the CPU MUX
switch on the affected CPU using smp_call_function_single()
in cases where cross-calling might otherwise be possible.
The one exception to this is during hotplug code paths,
where cross-calling is expected by design (since the target
CPU is not online and cannot be in retention).

Change-Id: I76b6de436e71da7979f30bdce841f414c26bfe44
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

msm: pm: send notification only for SPC and PC

Today the pm notification is sent for all the power
modes of each CPU. This is not necessary for shallow
power modes.

This change is to send the notification for only
standalone power collapse for each core and idle
power collapse of core0.

Change-Id: I9b3df3d72e43d645387c94b1b9c5da3bcf2f2e5f
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>
Signed-off-by: Sridhar Gujje <sgujje@codeaurora.org>

msm: pm: Add support for retention on each core

Allow each core on 8974 to enter retention and retain
the state of the CPU. On 8960 as hardware restriction does
not permit all cores to enter retention at the same time,
allow only core 0 to enter retention when all other cores
are offline to maintain backward compatibility.

CRs-fixed: 437281
Change-Id: I6690e901afc9fa3a27010c264fa3acc9a0722c1a
Signed-off-by: Priyanka Mathur <pmathur@codeaurora.org>
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>

msm: pm-8x60: Setup memory for save/restore cpu registers early

Cores can be offlined early in the boot cycle by certain kernel
drivers.
Ensure that the memory to save and restore the cpu registers is
ready and available early during the boot procedure.

CRs-Fixed: 460083
Change-Id: I925372f066386ceb1e85184d4c58863835c3e88e
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>

msm: hotplug: wait for hotplug completion event from secondary core

Primary core has to wait for hotplug completion event from secondary
core to avoid race between ongoing hotplug and already queued online
event. This also prevent CPU_DEAD notifiers from executing before the
SPM has completed the collapse of the CPU. CPU DEAD notifiers executing
early have been attributed to MDD hardware block for the CPU being
turned off prematurely, resulting in crashes.
The patch also adds support for probing with device tree for 8974
targets.

Change-Id: Ibd35a7c56f42f156a643ca6d531509f019b2a3be
CRs-fixed: 438314
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>

msm: pm-8x60: Use relative time for events

There is a bug when adjusting for event wakeups. The adjusted time
is being set in absolute mode incorrectly. Instead just use relative
times.

Without this core wakeups may not happen on time.

CRs-fixed: 486466
Change-Id: If625f25bd573b05befb6e0f922c80db646428b86
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>

msm: pm: add failed stats

for idle and suspend failed cases the stats
are not updated correctly, they are just added to
success bucket.

This patch is to log the failed stats separately.

Change-Id: I4b290944e3f4b74ada13ef0ba51b812c83b5ec5d
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>
Signed-off-by: Sridhar Gujje <sgujje@codeaurora.org>

msm:pm: Fix for race condition of starting cpu1 when cpu0 in PC.

There is a window where core sends ipi to secondary core and
wait for it to come online for 1 second. This would allow
core0 to go power collapse in a rare condition where core1
started booting and doesn't become online yet.

Fix this by not allowing power collapse on core0
if hot plug operation is in progress.

CRs-fixed: 545714.
Change-Id: I1ca503a2f09cd9a65c2fdcd41eb54466a1e486c5
Signed-off-by: Anil kumar mamidala <amami@codeaurora.org>

msm: pm-8x60: Remove timeout waiting for cpu to power collapse

The delays in the CPU_DYING notication path could result in the core
initiating the hotplug to send out CPU_DEAD notifications after
msm_pm_wait_cpu_shutdown() times out. This could result in a unknown
resets when regulator/clocks are disabled in the CPU_DEAD path. To
prevent unknown resets, wait infinitely to enter power collapse but
throw a warning after the 1ms mark.

The platform_cpu_kill() path is also executed in the reboot path when a
core tries to stop secondary cores. In these cases, platform_cpu_kill
shouldn't wait infinitely for the secondary cores to power collapse. To
circumvent this scenario, track dying cpus as a part of the hotplug
notification and skip waiting for the core to power collpase during
reboot path.

Change-Id: I144e95a6d019e897381d2bca62ab50ecefd56b5b
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>

msm: pm-8x60: Increase warn timeout for sleep sts check

Arm cores take longer time to enter sleep. Wait for longer
time before warning until the CPU goes to sleep state.

Change-Id: I15caa8b2b2560aa68a4f4967c3364533234584b7
Signed-off-by: Priyanka Mathur <pmathur@codeaurora.org>

msm: pm: Add API to enable/disable retention mode
On 8974 targets, retention mode voltage is controlled by the LDO
regulator, which in turn is powered through a ganged PMIC regulators. At
certain low voltage levels, the ganged PMIC will not be able to power
the LDO retention voltage. The regulator framework would invoke this
API to enable/disable retention mode in these scenarios.

When disabling retention modes, send a IPI to wakeup all online cores
out of idle, to ensure that no core is in a retention low power mode.
Also, disabled support for retention during suspend/hotplug operations
to ensure that a CPU isn't already in retention when the voltage is
lowered. This shouldn't have an effect on suspend, as the driver always
chooses the deepest sleep mode for suspend/hotplug.

Change-Id: I0af18168968c2aaf05ca99188d30762612c87de6
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>

msm: pm-8x60: Disable premption in msm_pm_enable_retention

msm_pm_retention_enable() makes smp_call_function_many to ensure that
when a retention is disabled, the cores come out of its low power mode.
Per the smp_call_function_many documentations, preemption should be
disabled before invoking the API.

CRs-fixed: 463188
Change-Id: I4ae9137e8f8e821af729becd0e2d6e6886d5e787
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>

msm: pm-8x60: Add early return to msm_pm_enable_retention()

If retention is already disabled, it is not necessary to send IPIs to
the running CPUs to wake them up. Insert an early return for this
scenario to reduce overhead during Krait rail voltage scaling, which
calls this API on every voltage change.

Change-Id: I5db0bafae187ff8a68488e86d4787df9c45787e4
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

msm: pm-8x60: Fix bug where CPU doesn't enter PC
When Krait regulator disables retention mode, an incorrect ordering of
the switch case disables power collapse.

Change-Id: Ic58b0356530e9ecb10d379e2f99d14016bc251e4
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>

msm: pm: support retention on CPU0 at suspend

Change-Id: I3dbaefda7009bb0d6e5abdb8518d41f0b0a0c380

msm: pm: Add support to query cpu status

During hotplug operation primary core is required to query
cpu registers to determine whether secondary core has
successfully shutdown.

Change-Id: I81bd47ba851698e86269652afe381b0571ca912a
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>

msm: pm: Add API to enable/disable retention mode
On 8974 targets, retention mode voltage is controlled by the LDO
regulator, which in turn is powered through a ganged PMIC regulators. At
certain low voltage levels, the ganged PMIC will not be able to power
the LDO retention voltage. The regulator framework would invoke this
API to enable/disable retention mode in these scenarios.

When disabling retention modes, send a IPI to wakeup all online cores
out of idle, to ensure that no core is in a retention low power mode.
Also, disabled support for retention during suspend/hotplug operations
to ensure that a CPU isn't already in retention when the voltage is
lowered. This shouldn't have an effect on suspend, as the driver always
chooses the deepest sleep mode for suspend/hotplug.

Change-Id: I0af18168968c2aaf05ca99188d30762612c87de6
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>

Fix up some missing things for Krait Retention

Change-Id: I8743ae3c4ce91338cf6090e9517c3d2202f5c095
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>
msm: iommu: re-use existing buffers for `extra' mappings
There is a bug on some hardware that requires us to overmap Iommu
mappings by 2x. Currently, we set aside a dummy buffer onto which we
map all of these dummy mappings. In general, for large mappings it's
nice to use the more efficient iommu_map_range instead of calling
iommu_map repeatedly. However, with our current approach in
msm_iommu_map_extra we can't use iommu_map_range for page_sizes larger
than the dummy buffer. To avoid wasting memory by increasing the size
of the dummy buffer, we can simply remap on top of the the buffer
being mapped in the first place. Since the second mapping should never
be used (besides by the buggy hardware) this should not be a problem.

Re-use existing buffers for all `extra' mappings. Essentially, map the
same physical address range twice. To be extra safe, make the second
mapping read-only.

Change-Id: I35462ad50de8da1f2befa3e3f0895925535cdc98
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
msm: Fix race condition in domain lookup

During lookup of domains we take a pointer to the root node
of the rb tree before taking the mutex to protect the rb tree.
However, the rb root node might change if another process updates
the rb tree after we take the pointer to the root node. This can
cause us to not find the entry that we are looking for.
Fix this by ensuring we have taken the mutex before getting the
root node pointer.

CRs-fixed: 493503
Change-Id: I4702740e486fda0cd92df0401d8e4706598a899b
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
gpu: ion: remove stale variable

Tracking the number of user mappings should be done in the Ion
heaps. Remove the variable that was used to track this in core Ion.

Change-Id: I715280515e3010bd002314aefe0ec8cdb37c143d
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
gpu: ion: Remove get_flags ioctl

There are no callers of the get flags ioctl. Remove it
before anyone tries to use it again.

Change-Id: I857ef705fc864cce49f671124b96bd9f47b66ab2
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
gpu: ion: Minimize allocation fallback delay

When we allocate from iommu heap we first try to allocate 1M pages. If
that fails we try 64K pages, which falls back to 4K pages. However,
we don't want to incur too much overhead when allocating with fallbacks
so we don't want the higher order page allocation to retry, perform
reclaim, or run memory compaction.

Configure the GFP flags to ensure that when we allocate pages greater
than order 0 we don't try to do any retries, reclaim, access emergency
pools, or run memory compaction. This will ensure lower memory allocation
latency for applications.

CRs-Fixed: 470389
Change-Id: Ibb3483dddbedbc733a1f7968821e7bc47bedffcd
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
gpu: ion: Remove code for reusable heap

The reusable feature is no longer supported. Remove
the associated code.

Change-Id: I7cf6eb302969287d629603fa0ea05ad9714bfb70
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>