From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
Gautham R Shenoy <ego@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Subject: [PATCH 7/8] powerpc/64s: idle do not hold reservation longer than required
Date: Tue, 14 Mar 2017 19:23:48 +1000 [thread overview]
Message-ID: <20170314092349.10981-8-npiggin@gmail.com> (raw)
In-Reply-To: <20170314092349.10981-1-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.
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 1c91dc35c559..3cb75907c5c5 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -488,12 +488,12 @@ 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.
@@ -501,7 +501,14 @@ 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
@@ -513,11 +520,6 @@ 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:[~2017-03-14 9:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-14 9:23 [PATCH 0/8] idle fixes and changes for POWER8 and POWER9 Nicholas Piggin
2017-03-14 9:23 ` [PATCH 1/8] powerpc/64s: move remaining system reset idle code into idle_book3s.S Nicholas Piggin
2017-03-14 9:23 ` [PATCH 2/8] powerpc/64s: stop using bit in HSPRG0 to test winkle Nicholas Piggin
2017-03-16 11:14 ` Gautham R Shenoy
2017-03-14 9:23 ` [PATCH 3/8] powerpc/64s: use alternative feature patching Nicholas Piggin
2017-03-16 11:21 ` Gautham R Shenoy
2017-03-14 9:23 ` [PATCH 4/8] powerpc/64s: fix POWER9 machine check handler from stop state Nicholas Piggin
2017-03-16 12:40 ` Mahesh Jagannath Salgaonkar
2017-03-16 13:05 ` Nicholas Piggin
2017-03-16 13:19 ` Gautham R Shenoy
2017-03-20 5:22 ` Mahesh Jagannath Salgaonkar
2017-03-17 2:49 ` Nicholas Piggin
2017-03-17 5:15 ` Nicholas Piggin
2017-03-14 9:23 ` [PATCH 5/8] powerpc/64s: use PACA_THREAD_IDLE_STATE only in POWER8 Nicholas Piggin
2017-03-16 11:54 ` Gautham R Shenoy
2017-03-16 12:16 ` Nicholas Piggin
2017-03-14 9:23 ` [PATCH 6/8] powerpc/64s: idle expand usable core idle state bits Nicholas Piggin
2017-03-16 12:10 ` Gautham R Shenoy
2017-03-14 9:23 ` Nicholas Piggin [this message]
2017-03-16 12:43 ` [PATCH 7/8] powerpc/64s: idle do not hold reservation longer than required Gautham R Shenoy
2017-03-16 12:55 ` Nicholas Piggin
2017-03-14 9:23 ` [PATCH 8/8] powerpc/64s: idle POWER8 avoid full state loss recovery when possible Nicholas Piggin
2017-03-16 16:12 ` Gautham R Shenoy
2017-03-17 5:24 ` Nicholas Piggin
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