Allwinner's MMC controller needs to run at double the card clock rate
for 8 bit DDR transfer modes. Interestingly, this is not needed for
4 bit DDR transfers.
Different clock delays are needed for 8 bit eMMC DDR, due to the
increased module clock rate. For the A80 though, the same values for
4 bit and 8 bit are shared. The new values for the other SoCs were from
A83T user manual's "new timing mode" default values, which describes
them in clock phase, rather than delay periods. These values were used
without any modification. They may not be correct, but they work.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
DDR transfer modes include UHS-1 DDR50 and MMC HS-DDR (or MMC_DDR52).
Consider MMC_DDR52 when setting clock delays.
Since MMC high speed mode goes up to 52 MHz instead of 50 MHz for SD,
and this number is visible in the capability macro, increase the
clock rate upper limit to 52 MHz.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The bus width is sometimes the actual bus width, and sometimes indices
to different arrays encoding the bus width. In my debugging case "2"
could mean 8-bit as well as 4-bit, which was extremly confusing. Let's
use the human-readable actual bus width in all places.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
In linux/mmc/host.h, mmc_card_is_removable() is already defined.
There is no reason that it doesn't use.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The sdhci_iproc_remove() is jsut a wrapper to sdhci_pltfm_unregister.
So use the sdhci_pltfm_unregister() for the .remove hook directly.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Since sdhci-iproc can support bcm2835 we need add the
compatible string to the binding.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Scott Branden <sbranden@broadcom.com>
Acked-by: Eric Anholt <eric@anholt.net>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Scott Branden <sbranden@broadcom.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Scott Branden from Broadcom said that the BCM2835 eMMC IP core is
very similar to IPROC and share most of the quirks. So use this driver
instead of separate one.
The sdhci-iproc contains a better workaround for the clock domain
crossing problem which doesn't need any delays. This results in a
better write performance.
Btw we get the rid of the SDHCI_CAPABILITIES hack in the sdhci_readl
function.
Suggested-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Acked-by: Scott Branden <sbranden@broadcom.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This patch moves the definition of the MMC capabilities
from the probe function into iproc platform data. After
that we are able to add support for another platform more
easily.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Suggested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Scott Branden <sbranden@broadcom.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
I had to use the source to determine what I need to write to 'test' so
that all tests are run. Let's mention this explicitly in 'testlist'.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
I don't see a reason why a host driver should depend on the card driver.
It also prevents that we can use the mmc_test driver. So, remove it.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
IMO this info is only useful for developers. Most users won't need this
information, since there is not much they can do about it.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
When DT based probing is used but the DMA request fails, the
driver will print uninitialized stack data from the rx_req
and tx_req variables, as indicated by this warning:
drivers/mmc/host/omap_hsmmc.c: In function 'omap_hsmmc_probe':
drivers/mmc/host/omap_hsmmc.c:2162:3: warning: 'rx_req' may be used uninitialized in this function [-Wmaybe-uninitialized]
dev_err(mmc_dev(host->mmc), "unable to obtain RX DMA engine channel %u\n", rx_req);
This removes the DMA request line number from the warning, which
is the easiest solution and won't hurt us any more as we are
planning to remove the legacy code path anyway.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This patch enables sdhci-acpi devices to suspend/resume asynchronously.
This will improve system suspend/resume speed. After enabling the
sdhci-acpi devices and all their child devices to suspend/resume
asynchronously on ASUS T100TA, the system suspend-to-idle time is
reduced from 1645ms to 1089ms, and the system resume time is reduced
from 940ms to 908ms.
Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This patch enables mmc hosts to suspend/resume asynchronously.
This will improve system suspend/resume speed. After applying
this patch and enabling all mmc hosts' child devices to
suspend/resume asynchronously on ASUS T100TA, the system
suspend-to-idle time is reduced from 1645ms to 1107ms, and the
system resume time is reduced from 940ms to 914ms.
Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
Acked-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
eMMC chips require 2 power supplies, vmmc for internal logic, and vqmmc
for driving output buffers. vqmmc also controls signaling voltage. Most
boards we've seen use the same regulator for both, nevertheless the 2
have different usages, and should be set separately.
This patch adds support for vqmmc regulator supply, including voltage
switching. The MMC core can use this to try different signaling voltages
for eMMC.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Let .set_ios() fail if mmc_regulator_set_ocr() fails to enable and set a
proper voltage for vmmc.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
sunxi_mmc_init_host() originated from Allwinner kernel sources. The
magic numbers written to various registers was never documented.
Add comments for values found in Allwinner user manuals.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The RPi firmware-based clocks driver can actually disable
unused clocks, so when switching to use it we ended up losing
our MMC clock once all devices were probed.
This patch adopts the changes from 1e5a0a9a58 ("mmc: sdhci-bcm2835:
Actually enable the clock") to sdhci-iproc.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Clock frequency values written to an mmc host should not be less than
the minimum clock frequency which the mmc host supports.
Signed-off-by: Yuan Juntao <juntaox.yuan@intel.com>
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This patch adopts the changes from 475c9e43bf ("mmc: sdhci-bcm2835:
Clean up platform allocations if sdhci init fails") to sdhci-iproc.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The Arason SD host controller supports set block count command (cmd23)
and high speed mode. This patch re-enable both of these features that
was disabled. For device that doesn't support high speed, it should
configure its capability register accordingly instead disables it
explicitly.
Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Since v4.3+, CONFIG_REGULATOR_PBIAS should be enabled (for platforms that
have PBIAS regulator) in order for MMC1 to work.
Add a more verbose print to help enable CONFIG_REGULATOR_PBIAS for users
using a olddefconfig or a custom .config.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Variable assignment just before return is redundant.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This issue was detected by using the Coccinelle software.
Two pointer checks could be repeated by the sdricoh_init_mmc() function
during error handling even if the relevant properties can be determined
for the involved variables before by source code analysis.
* This implementation detail could be improved by adjustments
for jump targets according to the Linux coding style convention.
* Drop an unnecessary initialisation for the variable "mmc" then.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
These variables will eventually be set to an appropriate value a bit later.
* host
* iobase
* result
Thus let us omit the explicit initialisation at the beginning.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Calling return copy_to_user(...) in an ioctl will not
do the right thing if there's a pagefault:
copy_to_user returns the number of bytes not copied
in this case.
Fix up kvm to do
return copy_to_user(...)) ? -EFAULT : 0;
everywhere.
Cc: stable@vger.kernel.org
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Now that other PTE fields have been moved out of the way, we can
expand the RPN field of the PTE on 64-bit Book 3S systems and align
it with the RPN field in the radix PTE format used by PowerISA v3.0
CPUs in radix mode. For 64k page size, this means we need to move
the _PAGE_COMBO and _PAGE_4K_PFN bits.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This moves the _PAGE_SPECIAL and _PAGE_SOFT_DIRTY bits in the Linux
PTE on 64-bit Book 3S systems to bit positions which are designated
for software use in the radix PTE format used by PowerISA v3.0 CPUs
in radix mode.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This moves the _PAGE_EXEC, _PAGE_RW and _PAGE_USER bits around in
the Linux PTE on 64-bit Book 3S systems to correspond with the bit
positions used in radix mode by PowerISA v3.0 CPUs. This also adds
a _PAGE_READ bit corresponding to the read permission bit in the
radix PTE. _PAGE_READ is currently unused but could possibly be used
in future to improve pte_protnone().
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This moves the _PAGE_HASHPTE, _PAGE_F_GIX and _PAGE_F_SECOND fields in
the Linux PTE on 64-bit Book 3S systems to the most significant byte.
Of the 5 bits, one is a software-use bit and the other four are
reserved bit positions in the PowerISA v3.0 radix PTE format.
Using these bits is OK because these bits are all to do with tracking
the HPTE(s) associated with the Linux PTE, and therefore won't be
needed in radix mode. This frees up bit positions in the lower two
bytes.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This changes _PAGE_PTE for 64-bit Book 3S processors from 0x1 to
0x4000_0000_0000_0000, because that bit is used as the L (leaf)
bit by PowerISA v3.0 CPUs in radix mode. The "leaf" bit indicates
that the PTE points to a page directly rather than another radix
level, which is what the _PAGE_PTE bit means.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This changes _PAGE_PRESENT for 64-bit Book 3S processors from 0x2 to
0x8000_0000_0000_0000, because that is where PowerISA v3.0 CPUs in
radix mode will expect to find it.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This changes the Linux page tables to store physical addresses
rather than kernel virtual addresses in the upper levels of the
tree (pgd, pud and pmd) for 64-bit Book 3S machines.
This also changes the hugepd pointers used to implement hugepages
when the base page size is 4k to store physical addresses rather than
virtual addresses (again just for 64-bit Book3S machines).
This frees up some high order bits, and will be needed with
PowerISA v3.0 machines which read the page table tree in hardware
in radix mode.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add detection for chain_key collision under CONFIG_DEBUG_LOCKDEP.
When a collision is detected the problem is reported and all lock
debugging is turned off.
Tested using liblockdep and the added tests before and after
applying the fix, confirming both that the code added for the
detection correctly reports the problem and that the fix actually
fixes it.
Tested tweaking lockdep to generate false collisions and
verified that the problem is reported and that lock debugging is
turned off.
Also tested with lockdep's test suite after applying the patch:
[ 0.000000] Good, all 253 testcases passed! |
Signed-off-by: Alfredo Alvarez Fernandez <alfredoalvarezernandez@gmail.com>
Cc: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sasha.levin@oracle.com
Link: http://lkml.kernel.org/r/1455864533-7536-4-git-send-email-alfredoalvarezernandez@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The chain_key hashing macro iterate_chain_key(key1, key2) does not
generate a new different value if both key1 and key2 are 0. In that
case the generated value is again 0. This can lead to collisions which
can result in lockdep not detecting deadlocks or circular
dependencies.
Avoid the problem by using class_idx (1-based) instead of class id
(0-based) as an input for the hashing macro 'key2' in
iterate_chain_key(key1, key2).
The use of class id created collisions in cases like the following:
1.- Consider an initial state in which no class has been acquired yet.
Under these circumstances an AA deadlock will not be detected by
lockdep:
lock [key1,key2]->new key (key1=old chain_key, key2=id)
--------------------------
A [0,0]->0
A [0,0]->0 (collision)
The newly generated chain_key collides with the one used before and as
a result the check for a deadlock is skipped
A simple test using liblockdep and a pthread mutex confirms the
problem: (omitting stack traces)
new class 0xe15038: 0x7ffc64950f20
acquire class [0xe15038] 0x7ffc64950f20
acquire class [0xe15038] 0x7ffc64950f20
hash chain already cached, key: 0000000000000000 tail class:
[0xe15038] 0x7ffc64950f20
2.- Consider an ABBA in 2 different tasks and no class yet acquired.
T1 [key1,key2]->new key T2[key1,key2]->new key
-- --
A [0,0]->0
B [0,1]->1
B [0,1]->1 (collision)
A
In this case the collision prevents lockdep from creating the new
dependency A->B. This in turn results in lockdep not detecting the
circular dependency when T2 acquires A.
Signed-off-by: Alfredo Alvarez Fernandez <alfredoalvarezernandez@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sasha.levin@oracle.com
Link: http://lkml.kernel.org/r/1455147212-2389-4-git-send-email-alfredoalvarezernandez@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This warning triggers if the .so library has already been linked:
triton:~/tip/tools/lib/lockdep> make
CC common.o
CC lockdep.o
CC rbtree.o
LD liblockdep-in.o
LD liblockdep.a
ln: failed to create symbolic link ‘liblockdep.so’: File exists
LD liblockdep.so.4.5.0-rc6
Overwrite the link.
Cc: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add test for AA and 2 threaded ABBA locking.
Rename AA.c to ABA.c since it was implementing an ABA instead of a pure
AA. Now both cases are covered.
The expected output for AA.c is that the process blocks and lockdep
reports a deadlock.
ABBA_2threads.c differs from ABBA.c in that lockdep keeps separate chains
of held locks per task. This can lead to different behaviour regarding
lock detection. The expected output for this test is that the process
blocks and lockdep reports a circular locking dependency.
These tests found a lockdep bug - fixed by the next commit.
Signed-off-by: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1455864533-7536-3-git-send-email-alfredoalvarezernandez@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This was added to the kernel code in <1658d35ead> ("list: Use
READ_ONCE() when testing for empty lists").
There's nothing special we need to do about it in userspace.
Signed-off-by: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1455864533-7536-2-git-send-email-alfredoalvarezernandez@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following upstream commit:
4a389810bc ("kernel/locking/lockdep.c: convert hash tables to hlists")
broke the tools/lib/lockdep build. Add trivial RCU wrappers to fix it.
These wrappers should probably be moved into their own header file.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Krinkin <krinkin.m.u@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move the __ARCH_SPIN_LOCK_UNLOCKED definition from qspinlock.h into
qspinlock_types.h.
The definition of __ARCH_SPIN_LOCK_UNLOCKED comes from the build arch's
include files; but on x86 when CONFIG_QUEUED_SPINLOCKS=y, it just
it's defined in asm-generic/qspinlock.h. In most cases, this doesn't
matter because linux/spinlock.h includes asm/spinlock.h, which for x86
includes asm-generic/qspinlock.h. However, any code that only includes
linux/mutex.h will break, because it only includes asm/spinlock_types.h.
For example, this breaks systemtap, which only includes mutex.h.
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1455907767-17821-1-git-send-email-dan.streetman@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Make use of wake-queues and enable the wakeup to occur after releasing the
wait_lock. This is similar to what we do with rtmutex top waiter,
slightly shortening the critical region and allow other waiters to
acquire the wait_lock sooner. In low contention cases it can also help
the recently woken waiter to find the wait_lock available (fastpath)
when it continues execution.
Reviewed-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Waiman Long <waiman.long@hpe.com>
Cc: Will Deacon <Will.Deacon@arm.com>
Link: http://lkml.kernel.org/r/20160125022343.GA3322@linux-uzut.site
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch enables the tracking of the number of slowpath locking
operations performed. This can be used to compare against the number
of lock stealing operations to see what percentage of locks are stolen
versus acquired via the regular slowpath.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1449778666-13593-2-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The newly introduced smp_cond_acquire() was used to replace the
slowpath lock acquisition loop. Similarly, the new function can also
be applied to the pending bit locking loop. This patch uses the new
function in that loop.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1449778666-13593-1-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch moves the lock stealing count tracking code into
pv_queued_spin_steal_lock() instead of via a jacket function simplifying
the code.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1449778666-13593-3-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Similar to commit b4b29f9485 ("locking/osq: Fix ordering of node
initialisation in osq_lock") the use of xchg_acquire() is
fundamentally broken with MCS like constructs.
Furthermore, it turns out we rely on the global transitivity of this
operation because the unlock path observes the pointer with a
READ_ONCE(), not an smp_load_acquire().
This is non-critical because the MCS code isn't actually used and
mostly serves as documentation, a stepping stone to the more complex
things we've build on top of the idea.
Reported-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: 3552a07a9c ("locking/mcs: Use acquire/release semantics")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
