From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 7/9] powerpc/64s: idle do not hold reservation longer than required
Date: Wed, 19 Apr 2017 23:05:49 +1000 [thread overview]
Message-ID: <20170419130551.32378-8-npiggin@gmail.com> (raw)
In-Reply-To: <20170419130551.32378-1-npiggin@gmail.com>
When taking the core idle state lock, grab it immediately like a regular
lock, rather than adding more tests in there. Holding the lock keeps it
stable, so there is no need to do it whole holding the reservation.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/idle_book3s.S | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 13b7044c1541..db60e051fb1c 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -569,12 +569,12 @@ BEGIN_FTR_SECTION
CHECK_HMI_INTERRUPT
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
- lbz r7,PACA_THREAD_MASK(r13)
ld r14,PACA_CORE_IDLE_STATE_PTR(r13)
-lwarx_loop2:
- lwarx r15,0,r14
- andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
+ lbz r7,PACA_THREAD_MASK(r13)
+
/*
+ * Take the core lock to synchronize against other threads.
+ *
* Lock bit is set in one of the 2 cases-
* a. In the sleep/winkle enter path, the last thread is executing
* fastsleep workaround code.
@@ -582,7 +582,14 @@ lwarx_loop2:
* workaround undo code or resyncing timebase or restoring context
* In either case loop until the lock bit is cleared.
*/
+1:
+ lwarx r15,0,r14
+ andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h
bnel- core_idle_lock_held
+ oris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
+ stwcx. r15,0,r14
+ bne- 1b
+ isync
andi. r9,r15,PNV_CORE_IDLE_THREAD_BITS
cmpwi cr2,r9,0
@@ -594,11 +601,6 @@ lwarx_loop2:
* cr4 - gt or eq if waking up from complete hypervisor state loss.
*/
- oris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h
- stwcx. r15,0,r14
- bne- lwarx_loop2
- isync
-
BEGIN_FTR_SECTION
lbz r4,PACA_SUBCORE_SIBLING_MASK(r13)
and r4,r4,r15
--
2.11.0
next prev parent reply other threads:[~2017-04-19 13:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 13:05 [PATCH v2 0/9] idle fixes and changes for POWER8 and POWER9 Nicholas Piggin
2017-04-19 13:05 ` [PATCH 1/9] powerpc/64s: Remove unnecessary relocation branch from idle handler Nicholas Piggin
2017-04-23 11:53 ` [1/9] " Michael Ellerman
2017-04-19 13:05 ` [PATCH 2/9] powerpc/64s: move remaining system reset idle code into idle_book3s.S Nicholas Piggin
2017-04-19 13:05 ` [PATCH 3/9] powerpc/64s: stop using bit in HSPRG0 to test winkle Nicholas Piggin
2017-04-19 13:05 ` [PATCH 4/9] powerpc/64s: use alternative feature patching Nicholas Piggin
2017-04-19 13:05 ` [PATCH 5/9] powerpc/64s: fix POWER9 machine check handler from stop state Nicholas Piggin
2017-04-19 13:05 ` [PATCH 6/9] powerpc/64s: idle expand core idle state bits Nicholas Piggin
2017-04-19 13:05 ` Nicholas Piggin [this message]
2017-04-19 13:05 ` [PATCH 8/9] powerpc/64s: idle POWER8 avoid full state loss recovery where possible Nicholas Piggin
2017-04-19 13:05 ` [PATCH 9/9] powerpc/64s: Simplify POWER9 DD1 idle workaround code Nicholas Piggin
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