linux_dsm_epyc7002/arch/tile
Peter Zijlstra 726328d92a locking/spinlock, arch: Update and fix spin_unlock_wait() implementations
This patch updates/fixes all spin_unlock_wait() implementations.

The update is in semantics; where it previously was only a control
dependency, we now upgrade to a full load-acquire to match the
store-release from the spin_unlock() we waited on. This ensures that
when spin_unlock_wait() returns, we're guaranteed to observe the full
critical section we waited on.

This fixes a number of spin_unlock_wait() users that (not
unreasonably) rely on this.

I also fixed a number of ticket lock versions to only wait on the
current lock holder, instead of for a full unlock, as this is
sufficient.

Furthermore; again for ticket locks; I added an smp_rmb() in between
the initial ticket load and the spin loop testing the current value
because I could not convince myself the address dependency is
sufficient, esp. if the loads are of different sizes.

I'm more than happy to remove this smp_rmb() again if people are
certain the address dependency does indeed work as expected.

Note: PPC32 will be fixed independently

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: chris@zankel.net
Cc: cmetcalf@mellanox.com
Cc: davem@davemloft.net
Cc: dhowells@redhat.com
Cc: james.hogan@imgtec.com
Cc: jejb@parisc-linux.org
Cc: linux@armlinux.org.uk
Cc: mpe@ellerman.id.au
Cc: ralf@linux-mips.org
Cc: realmz6@gmail.com
Cc: rkuo@codeaurora.org
Cc: rth@twiddle.net
Cc: schwidefsky@de.ibm.com
Cc: tony.luck@intel.com
Cc: vgupta@synopsys.com
Cc: ysato@users.sourceforge.jp
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14 11:55:15 +02:00
..
configs Merge branch 'akpm' (patches from Andrew) 2016-05-23 19:42:28 -07:00
gxio Fix typo 2016-05-23 12:17:22 -04:00
include locking/barriers, tile: Provide TILE specific smp_acquire__after_ctrl_dep() 2016-06-14 11:55:15 +02:00
kernel Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-05-25 17:05:40 -07:00
kvm rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
lib locking/spinlock, arch: Update and fix spin_unlock_wait() implementations 2016-06-14 11:55:15 +02:00
mm tile: mm: use hugetlb_bad_size() 2016-05-19 19:12:14 -07:00
Kbuild arch/tile: core support for Tilera 32-bit chips. 2010-06-04 17:11:18 -04:00
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 2016-05-23 19:05:11 -07:00
Kconfig.debug tile: remove DEBUG_EXTRA_FLAGS kernel config option 2013-09-03 14:52:17 -04:00
Makefile tile: remove DEBUG_EXTRA_FLAGS kernel config option 2013-09-03 14:52:17 -04:00