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Message-ID: <20160825154331.GI10138@twins.programming.kicks-ass.net>
Date: Thu, 25 Aug 2016 17:43:31 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Jason Low <jason.low2@....com>
Cc: Davidlohr Bueso <dave@...olabs.net>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Waiman Long <waiman.long@....com>,
Ding Tianhong <dingtianhong@...wei.com>,
Thomas Gleixner <tglx@...utronix.de>,
Will Deacon <Will.Deacon@....com>,
Ingo Molnar <mingo@...hat.com>,
Imre Deak <imre.deak@...el.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Tim Chen <tim.c.chen@...ux.intel.com>,
"Paul E. McKenney" <paulmck@...ibm.com>, jason.low2@...com
Subject: Re: [RFC][PATCH 0/3] locking/mutex: Rewrite basic mutex
On Tue, Aug 23, 2016 at 06:13:43PM -0700, Jason Low wrote:
> I tested this patch on an 8 socket system with the high_systime AIM7
> workload with diskfs. The patch provided big performance improvements in
> terms of throughput in the highly contended cases.
>
> -------------------------------------------------
> | users | avg throughput | avg throughput |
> | without patch | with patch |
> -------------------------------------------------
> | 10 - 90 | 13,943 JPM | 14,432 JPM |
> -------------------------------------------------
> | 100 - 900 | 75,475 JPM | 102,922 JPM |
> -------------------------------------------------
> | 1000 - 1900 | 77,299 JPM | 115,271 JPM |
> -------------------------------------------------
>
> Unfortunately, at 2000 users, the modified kernel locked up.
>
> # INFO: task reaim:<#> blocked for more than 120 seconds.
>
> So something appears to be buggy.
So with the previously given changes to reaim, I get the below results
on my 4 socket Haswell with the new version of 1/3 (also below).
I still need to update 3/3..
Note that I think my reaim change wrecked the jobs/min calculation
somehow, as it keeps increasing. I do think however that the numbers are
comparable between runs, since they're wrecked the same way.
********************* Data Separator *****************************
Title: hsw-ex
Kernel: 4.8.0-rc3-00185-g9f55477
Date: Thu Aug 25 15:29:51 CEST 2016
Command: /usr/local/share/reaim/reaim -O60 -s10 -e2000 -t -j100 -i[10|100] -y -f /usr/local/share/reaim/workfile.high_systime
Workload: high_systime
Time: 13.44 mins == 73 mins, 26 secs
Jobs/min/ Jobs/sec/ Time: Time: Time: Time: Running child time
Forks Jobs/min child child parent childU childS std_dev JTI :max :min
10 1040.00 104.00 1.73 60.00 51.87 507.73 0.00 100.00 60.00 60.00
20 1600.00 80.00 1.33 78.00 88.23 1345.41 0.00 100.00 78.00 78.00
30 2127.27 70.91 1.18 88.00 133.77 2358.77 0.00 100.00 88.00 88.00
40 2599.73 64.99 1.08 96.01 179.21 3482.58 0.00 99.00 96.01 96.00
50 3088.50 61.77 1.03 101.02 203.39 4627.08 0.01 99.00 101.02 101.00
60 3531.08 58.85 0.98 106.03 241.29 5823.03 0.01 99.00 106.03 106.00
70 3969.83 56.71 0.95 110.03 282.49 7146.39 0.01 99.00 110.03 110.00
80 4377.80 54.72 0.91 114.03 298.70 8467.74 0.01 99.00 114.03 114.00
90 4797.95 53.31 0.89 117.05 304.00 9909.76 0.01 99.00 117.05 117.00
100 5198.27 51.98 0.87 120.04 303.13 11172.37 0.01 99.00 120.04 120.00
200 9038.89 45.19 0.75 138.07 354.27 19239.86 0.01 99.00 138.07 138.00
300 12642.67 42.14 0.70 148.07 380.76 20866.01 0.01 99.00 148.07 148.00
400 15970.31 39.93 0.67 156.29 406.51 21991.01 0.08 99.00 156.29 156.00
500 19365.65 38.73 0.65 161.11 417.03 22665.03 0.01 99.00 161.11 161.00
600 22537.92 37.56 0.63 166.12 431.56 23355.16 0.01 99.00 166.12 166.00
700 25536.39 36.48 0.61 171.05 444.61 24013.11 0.33 99.00 171.05 170.00
800 28673.18 35.84 0.60 174.10 454.69 24450.15 0.01 99.00 174.10 174.01
900 31596.71 35.11 0.59 177.74 467.94 24918.53 0.19 99.00 177.74 177.00
1000 34651.27 34.65 0.58 180.08 475.11 25255.57 0.02 99.00 180.08 180.00
1100 37679.09 34.25 0.57 182.17 477.46 25515.20 0.02 99.00 182.17 182.02
1200 40675.76 33.90 0.56 184.09 484.20 25780.88 0.02 99.00 184.09 184.00
1300 43573.08 33.52 0.56 186.17 491.92 26039.82 0.02 99.00 186.17 186.00
1400 46398.98 33.14 0.55 188.28 497.82 26317.58 0.04 99.00 188.28 188.01
1500 48977.03 32.65 0.54 191.11 503.36 26676.47 0.27 99.00 191.11 190.00
1600 51940.48 32.46 0.54 192.22 509.20 26824.58 0.02 99.00 192.22 192.00
1700 54929.58 32.31 0.54 193.12 513.25 26939.84 0.02 99.00 193.12 193.01
1800 57432.12 31.91 0.53 195.57 519.41 27249.93 0.11 99.00 195.57 195.00
1900 60437.38 31.81 0.53 196.17 523.50 27331.56 0.03 99.00 196.17 196.01
2000 62950.82 31.48 0.52 198.25 530.96 27587.86 0.02 99.00 198.25 198.00
********************* Data Separator *****************************
Title: hsw-ex
Kernel: 4.8.0-rc3-00185-g9f55477-dirty
Date: Thu Aug 25 17:20:37 CEST 2016
Command: /usr/local/share/reaim/reaim -O60 -s10 -e2000 -t -j100 -i[10|100] -y -f /usr/local/share/reaim/workfile.high_systime
Workload: high_systime
Time: 13.40 mins == 73 mins, 24 secs
Jobs/min/ Jobs/sec/ Time: Time: Time: Time: Running child time
Forks Jobs/min child child parent childU childS std_dev JTI :max :min
10 1039.83 103.98 1.73 60.01 42.92 491.23 -nan -2147483648.00 60.01 60.01
20 1599.79 79.99 1.33 78.01 92.46 1406.04 0.00 99.00 78.01 78.00
30 2127.27 70.91 1.18 88.00 146.93 2330.10 0.00 100.00 88.00 88.00
40 2599.46 64.99 1.08 96.02 187.90 3483.81 0.01 99.00 96.02 96.00
50 3088.50 61.77 1.03 101.02 207.02 4659.42 0.01 99.00 101.02 101.00
60 3531.08 58.85 0.98 106.03 249.31 5855.74 0.01 99.00 106.03 106.00
70 3969.47 56.71 0.95 110.04 287.04 7075.68 0.01 99.00 110.04 110.01
80 4377.80 54.72 0.91 114.03 300.31 8420.47 0.01 99.00 114.03 114.00
90 4798.77 53.32 0.89 117.03 308.47 9801.80 0.01 99.00 117.03 117.00
100 5198.27 51.98 0.87 120.04 314.72 11220.78 0.01 99.00 120.04 120.00
200 9038.89 45.19 0.75 138.07 370.78 19229.77 0.01 99.00 138.07 138.00
300 12643.52 42.15 0.70 148.06 403.30 20834.52 0.01 99.00 148.06 148.00
400 15993.85 39.98 0.67 156.06 429.17 21952.93 0.01 99.00 156.06 156.00
500 19339.24 38.68 0.64 161.33 442.51 22654.86 0.08 99.00 161.33 161.00
600 22542.00 37.57 0.63 166.09 453.04 23334.89 0.01 99.00 166.09 166.00
700 25653.37 36.65 0.61 170.27 467.00 23890.76 0.06 99.00 170.27 170.00
800 28664.94 35.83 0.60 174.15 477.22 24423.89 0.01 99.00 174.15 174.00
900 31685.85 35.21 0.59 177.24 489.02 24826.23 0.03 99.00 177.24 177.01
1000 34643.57 34.64 0.58 180.12 506.51 25232.11 0.02 99.00 180.12 180.00
1100 37693.57 34.27 0.57 182.10 542.31 25458.35 0.02 99.00 182.10 182.00
1200 40675.76 33.90 0.56 184.09 546.54 25718.16 0.02 99.00 184.09 184.00
1300 43575.42 33.52 0.56 186.16 551.71 25990.72 0.02 99.00 186.16 186.00
1400 46406.37 33.15 0.55 188.25 562.14 26247.12 0.02 99.00 188.25 188.01
1500 49203.60 32.80 0.55 190.23 574.29 26506.14 0.03 99.00 190.23 190.00
1600 51970.23 32.48 0.54 192.11 574.22 26771.98 0.02 99.00 192.11 192.00
1700 54646.61 32.15 0.54 194.12 581.82 27023.52 0.23 99.00 194.12 193.00
1800 57538.04 31.97 0.53 195.21 585.85 27137.02 0.02 99.00 195.21 195.00
1900 60434.30 31.81 0.53 196.18 596.44 27277.20 0.02 99.00 196.18 196.00
2000 62973.05 31.49 0.52 198.18 595.86 27527.66 0.03 99.00 198.17 198.00
---
arch/alpha/include/asm/mutex.h | 9 --
arch/arc/include/asm/mutex.h | 18 ---
arch/arm/include/asm/mutex.h | 21 ---
arch/arm64/include/asm/Kbuild | 1 -
arch/avr32/include/asm/mutex.h | 9 --
arch/blackfin/include/asm/Kbuild | 1 -
arch/c6x/include/asm/mutex.h | 6 -
arch/cris/include/asm/mutex.h | 9 --
arch/frv/include/asm/mutex.h | 9 --
arch/h8300/include/asm/mutex.h | 9 --
arch/hexagon/include/asm/mutex.h | 8 -
arch/ia64/include/asm/mutex.h | 90 -----------
arch/m32r/include/asm/mutex.h | 9 --
arch/m68k/include/asm/Kbuild | 1 -
arch/metag/include/asm/Kbuild | 1 -
arch/microblaze/include/asm/mutex.h | 1 -
arch/mips/include/asm/Kbuild | 1 -
arch/mn10300/include/asm/mutex.h | 16 --
arch/nios2/include/asm/mutex.h | 1 -
arch/openrisc/include/asm/mutex.h | 27 ----
arch/parisc/include/asm/Kbuild | 1 -
arch/powerpc/include/asm/mutex.h | 132 ----------------
arch/s390/include/asm/mutex.h | 9 --
arch/score/include/asm/mutex.h | 6 -
arch/sh/include/asm/mutex-llsc.h | 109 -------------
arch/sh/include/asm/mutex.h | 12 --
arch/sparc/include/asm/Kbuild | 1 -
arch/tile/include/asm/Kbuild | 1 -
arch/um/include/asm/Kbuild | 1 -
arch/unicore32/include/asm/mutex.h | 20 ---
arch/x86/include/asm/mutex.h | 5 -
arch/x86/include/asm/mutex_32.h | 110 -------------
arch/x86/include/asm/mutex_64.h | 127 ---------------
arch/xtensa/include/asm/mutex.h | 9 --
include/asm-generic/mutex-dec.h | 88 -----------
include/asm-generic/mutex-null.h | 19 ---
include/asm-generic/mutex-xchg.h | 120 --------------
include/asm-generic/mutex.h | 9 --
include/linux/mutex-debug.h | 24 ---
include/linux/mutex.h | 46 ++++--
kernel/locking/mutex-debug.c | 13 --
kernel/locking/mutex-debug.h | 10 --
kernel/locking/mutex.c | 307 +++++++++++++++---------------------
kernel/locking/mutex.h | 26 ---
kernel/sched/core.c | 2 +-
45 files changed, 155 insertions(+), 1299 deletions(-)
diff --git a/arch/alpha/include/asm/mutex.h b/arch/alpha/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/alpha/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/arc/include/asm/mutex.h b/arch/arc/include/asm/mutex.h
deleted file mode 100644
index a2f88ff9f506..000000000000
--- a/arch/arc/include/asm/mutex.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-/*
- * xchg() based mutex fast path maintains a state of 0 or 1, as opposed to
- * atomic dec based which can "count" any number of lock contenders.
- * This ideally needs to be fixed in core, but for now switching to dec ver.
- */
-#if defined(CONFIG_SMP) && (CONFIG_NR_CPUS > 2)
-#include <asm-generic/mutex-dec.h>
-#else
-#include <asm-generic/mutex-xchg.h>
-#endif
diff --git a/arch/arm/include/asm/mutex.h b/arch/arm/include/asm/mutex.h
deleted file mode 100644
index 87c044910fe0..000000000000
--- a/arch/arm/include/asm/mutex.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * arch/arm/include/asm/mutex.h
- *
- * ARM optimized mutex locking primitives
- *
- * Please look into asm-generic/mutex-xchg.h for a formal definition.
- */
-#ifndef _ASM_MUTEX_H
-#define _ASM_MUTEX_H
-/*
- * On pre-ARMv6 hardware this results in a swp-based implementation,
- * which is the most efficient. For ARMv6+, we have exclusive memory
- * accessors and use atomic_dec to avoid the extra xchg operations
- * on the locking slowpaths.
- */
-#if __LINUX_ARM_ARCH__ < 6
-#include <asm-generic/mutex-xchg.h>
-#else
-#include <asm-generic/mutex-dec.h>
-#endif
-#endif /* _ASM_MUTEX_H */
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index f43d2c44c765..0b95418fd5ca 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -26,7 +26,6 @@ generic-y += mm-arch-hooks.h
generic-y += mman.h
generic-y += msgbuf.h
generic-y += msi.h
-generic-y += mutex.h
generic-y += pci.h
generic-y += poll.h
generic-y += preempt.h
diff --git a/arch/avr32/include/asm/mutex.h b/arch/avr32/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/avr32/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/blackfin/include/asm/Kbuild b/arch/blackfin/include/asm/Kbuild
index 91d49c0a3118..2fb67b59d188 100644
--- a/arch/blackfin/include/asm/Kbuild
+++ b/arch/blackfin/include/asm/Kbuild
@@ -24,7 +24,6 @@ generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mman.h
generic-y += msgbuf.h
-generic-y += mutex.h
generic-y += param.h
generic-y += percpu.h
generic-y += pgalloc.h
diff --git a/arch/c6x/include/asm/mutex.h b/arch/c6x/include/asm/mutex.h
deleted file mode 100644
index 7a7248e0462d..000000000000
--- a/arch/c6x/include/asm/mutex.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef _ASM_C6X_MUTEX_H
-#define _ASM_C6X_MUTEX_H
-
-#include <asm-generic/mutex-null.h>
-
-#endif /* _ASM_C6X_MUTEX_H */
diff --git a/arch/cris/include/asm/mutex.h b/arch/cris/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/cris/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/frv/include/asm/mutex.h b/arch/frv/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/frv/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/h8300/include/asm/mutex.h b/arch/h8300/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/h8300/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/hexagon/include/asm/mutex.h b/arch/hexagon/include/asm/mutex.h
deleted file mode 100644
index 58b52de1bc22..000000000000
--- a/arch/hexagon/include/asm/mutex.h
+++ /dev/null
@@ -1,8 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-#include <asm-generic/mutex-xchg.h>
diff --git a/arch/ia64/include/asm/mutex.h b/arch/ia64/include/asm/mutex.h
deleted file mode 100644
index 28cb819e0ff9..000000000000
--- a/arch/ia64/include/asm/mutex.h
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * ia64 implementation of the mutex fastpath.
- *
- * Copyright (C) 2006 Ken Chen <kenneth.w.chen@...el.com>
- *
- */
-
-#ifndef _ASM_MUTEX_H
-#define _ASM_MUTEX_H
-
-/**
- * __mutex_fastpath_lock - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 1
- *
- * Change the count from 1 to a value lower than 1, and call <fail_fn> if
- * it wasn't 1 originally. This function MUST leave the value lower than
- * 1 even when the "1" assertion wasn't true.
- */
-static inline void
-__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(ia64_fetchadd4_acq(count, -1) != 1))
- fail_fn(count);
-}
-
-/**
- * __mutex_fastpath_lock_retval - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- *
- * Change the count from 1 to a value lower than 1. This function returns 0
- * if the fastpath succeeds, or -1 otherwise.
- */
-static inline int
-__mutex_fastpath_lock_retval(atomic_t *count)
-{
- if (unlikely(ia64_fetchadd4_acq(count, -1) != 1))
- return -1;
- return 0;
-}
-
-/**
- * __mutex_fastpath_unlock - try to promote the count from 0 to 1
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 0
- *
- * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
- * In the failure case, this function is allowed to either set the value to
- * 1, or to set it to a value lower than 1.
- *
- * If the implementation sets it to a value of lower than 1, then the
- * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
- * to return 0 otherwise.
- */
-static inline void
-__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- int ret = ia64_fetchadd4_rel(count, 1);
- if (unlikely(ret < 0))
- fail_fn(count);
-}
-
-#define __mutex_slowpath_needs_to_unlock() 1
-
-/**
- * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
- *
- * @count: pointer of type atomic_t
- * @fail_fn: fallback function
- *
- * Change the count from 1 to a value lower than 1, and return 0 (failure)
- * if it wasn't 1 originally, or return 1 (success) otherwise. This function
- * MUST leave the value lower than 1 even when the "1" assertion wasn't true.
- * Additionally, if the value was < 0 originally, this function must not leave
- * it to 0 on failure.
- *
- * If the architecture has no effective trylock variant, it should call the
- * <fail_fn> spinlock-based trylock variant unconditionally.
- */
-static inline int
-__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
-{
- if (atomic_read(count) == 1 && cmpxchg_acq(count, 1, 0) == 1)
- return 1;
- return 0;
-}
-
-#endif
diff --git a/arch/m32r/include/asm/mutex.h b/arch/m32r/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/m32r/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index eb85bd9c6180..1f2e5d31cb24 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -20,7 +20,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mman.h
-generic-y += mutex.h
generic-y += percpu.h
generic-y += preempt.h
generic-y += resource.h
diff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild
index 29acb89daaaa..167150c701d1 100644
--- a/arch/metag/include/asm/Kbuild
+++ b/arch/metag/include/asm/Kbuild
@@ -27,7 +27,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += msgbuf.h
-generic-y += mutex.h
generic-y += param.h
generic-y += pci.h
generic-y += percpu.h
diff --git a/arch/microblaze/include/asm/mutex.h b/arch/microblaze/include/asm/mutex.h
deleted file mode 100644
index ff6101aa2c71..000000000000
--- a/arch/microblaze/include/asm/mutex.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild
index 9740066cc631..3269b742a75e 100644
--- a/arch/mips/include/asm/Kbuild
+++ b/arch/mips/include/asm/Kbuild
@@ -9,7 +9,6 @@ generic-y += irq_work.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
-generic-y += mutex.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/mn10300/include/asm/mutex.h b/arch/mn10300/include/asm/mutex.h
deleted file mode 100644
index 84f5490c6fb4..000000000000
--- a/arch/mn10300/include/asm/mutex.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/* MN10300 Mutex fastpath
- *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@...hat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- *
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-#include <asm-generic/mutex-null.h>
diff --git a/arch/nios2/include/asm/mutex.h b/arch/nios2/include/asm/mutex.h
deleted file mode 100644
index ff6101aa2c71..000000000000
--- a/arch/nios2/include/asm/mutex.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/openrisc/include/asm/mutex.h b/arch/openrisc/include/asm/mutex.h
deleted file mode 100644
index b85a0cfa9fc9..000000000000
--- a/arch/openrisc/include/asm/mutex.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * OpenRISC Linux
- *
- * Linux architectural port borrowing liberally from similar works of
- * others. All original copyrights apply as per the original source
- * declaration.
- *
- * OpenRISC implementation:
- * Copyright (C) 2003 Matjaz Breskvar <phoenix@...mi.com>
- * Copyright (C) 2010-2011 Jonas Bonn <jonas@...thpole.se>
- * et al.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- */
-
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index f9b3a81aefcd..91f53c07f410 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -16,7 +16,6 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
-generic-y += mutex.h
generic-y += param.h
generic-y += percpu.h
generic-y += poll.h
diff --git a/arch/powerpc/include/asm/mutex.h b/arch/powerpc/include/asm/mutex.h
deleted file mode 100644
index 078155fa1189..000000000000
--- a/arch/powerpc/include/asm/mutex.h
+++ /dev/null
@@ -1,132 +0,0 @@
-/*
- * Optimised mutex implementation of include/asm-generic/mutex-dec.h algorithm
- */
-#ifndef _ASM_POWERPC_MUTEX_H
-#define _ASM_POWERPC_MUTEX_H
-
-static inline int __mutex_cmpxchg_lock(atomic_t *v, int old, int new)
-{
- int t;
-
- __asm__ __volatile__ (
-"1: lwarx %0,0,%1 # mutex trylock\n\
- cmpw 0,%0,%2\n\
- bne- 2f\n"
- PPC405_ERR77(0,%1)
-" stwcx. %3,0,%1\n\
- bne- 1b"
- PPC_ACQUIRE_BARRIER
- "\n\
-2:"
- : "=&r" (t)
- : "r" (&v->counter), "r" (old), "r" (new)
- : "cc", "memory");
-
- return t;
-}
-
-static inline int __mutex_dec_return_lock(atomic_t *v)
-{
- int t;
-
- __asm__ __volatile__(
-"1: lwarx %0,0,%1 # mutex lock\n\
- addic %0,%0,-1\n"
- PPC405_ERR77(0,%1)
-" stwcx. %0,0,%1\n\
- bne- 1b"
- PPC_ACQUIRE_BARRIER
- : "=&r" (t)
- : "r" (&v->counter)
- : "cc", "memory");
-
- return t;
-}
-
-static inline int __mutex_inc_return_unlock(atomic_t *v)
-{
- int t;
-
- __asm__ __volatile__(
- PPC_RELEASE_BARRIER
-"1: lwarx %0,0,%1 # mutex unlock\n\
- addic %0,%0,1\n"
- PPC405_ERR77(0,%1)
-" stwcx. %0,0,%1 \n\
- bne- 1b"
- : "=&r" (t)
- : "r" (&v->counter)
- : "cc", "memory");
-
- return t;
-}
-
-/**
- * __mutex_fastpath_lock - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 1
- *
- * Change the count from 1 to a value lower than 1, and call <fail_fn> if
- * it wasn't 1 originally. This function MUST leave the value lower than
- * 1 even when the "1" assertion wasn't true.
- */
-static inline void
-__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(__mutex_dec_return_lock(count) < 0))
- fail_fn(count);
-}
-
-/**
- * __mutex_fastpath_lock_retval - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- *
- * Change the count from 1 to a value lower than 1. This function returns 0
- * if the fastpath succeeds, or -1 otherwise.
- */
-static inline int
-__mutex_fastpath_lock_retval(atomic_t *count)
-{
- if (unlikely(__mutex_dec_return_lock(count) < 0))
- return -1;
- return 0;
-}
-
-/**
- * __mutex_fastpath_unlock - try to promote the count from 0 to 1
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 0
- *
- * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
- * In the failure case, this function is allowed to either set the value to
- * 1, or to set it to a value lower than 1.
- */
-static inline void
-__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(__mutex_inc_return_unlock(count) <= 0))
- fail_fn(count);
-}
-
-#define __mutex_slowpath_needs_to_unlock() 1
-
-/**
- * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
- *
- * @count: pointer of type atomic_t
- * @fail_fn: fallback function
- *
- * Change the count from 1 to 0, and return 1 (success), or if the count
- * was not 1, then return 0 (failure).
- */
-static inline int
-__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
-{
- if (likely(atomic_read(count) == 1 && __mutex_cmpxchg_lock(count, 1, 0) == 1))
- return 1;
- return 0;
-}
-
-#endif
diff --git a/arch/s390/include/asm/mutex.h b/arch/s390/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/s390/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/score/include/asm/mutex.h b/arch/score/include/asm/mutex.h
deleted file mode 100644
index 10d48fe4db97..000000000000
--- a/arch/score/include/asm/mutex.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef _ASM_SCORE_MUTEX_H
-#define _ASM_SCORE_MUTEX_H
-
-#include <asm-generic/mutex-dec.h>
-
-#endif /* _ASM_SCORE_MUTEX_H */
diff --git a/arch/sh/include/asm/mutex-llsc.h b/arch/sh/include/asm/mutex-llsc.h
deleted file mode 100644
index dad29b687bd3..000000000000
--- a/arch/sh/include/asm/mutex-llsc.h
+++ /dev/null
@@ -1,109 +0,0 @@
-/*
- * arch/sh/include/asm/mutex-llsc.h
- *
- * SH-4A optimized mutex locking primitives
- *
- * Please look into asm-generic/mutex-xchg.h for a formal definition.
- */
-#ifndef __ASM_SH_MUTEX_LLSC_H
-#define __ASM_SH_MUTEX_LLSC_H
-
-/*
- * Attempting to lock a mutex on SH4A is done like in ARMv6+ architecure.
- * with a bastardized atomic decrement (it is not a reliable atomic decrement
- * but it satisfies the defined semantics for our purpose, while being
- * smaller and faster than a real atomic decrement or atomic swap.
- * The idea is to attempt decrementing the lock value only once. If once
- * decremented it isn't zero, or if its store-back fails due to a dispute
- * on the exclusive store, we simply bail out immediately through the slow
- * path where the lock will be reattempted until it succeeds.
- */
-static inline void
-__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- int __done, __res;
-
- __asm__ __volatile__ (
- "movli.l @%2, %0 \n"
- "add #-1, %0 \n"
- "movco.l %0, @%2 \n"
- "movt %1 \n"
- : "=&z" (__res), "=&r" (__done)
- : "r" (&(count)->counter)
- : "t");
-
- if (unlikely(!__done || __res != 0))
- fail_fn(count);
-}
-
-static inline int
-__mutex_fastpath_lock_retval(atomic_t *count)
-{
- int __done, __res;
-
- __asm__ __volatile__ (
- "movli.l @%2, %0 \n"
- "add #-1, %0 \n"
- "movco.l %0, @%2 \n"
- "movt %1 \n"
- : "=&z" (__res), "=&r" (__done)
- : "r" (&(count)->counter)
- : "t");
-
- if (unlikely(!__done || __res != 0))
- __res = -1;
-
- return __res;
-}
-
-static inline void
-__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- int __done, __res;
-
- __asm__ __volatile__ (
- "movli.l @%2, %0 \n\t"
- "add #1, %0 \n\t"
- "movco.l %0, @%2 \n\t"
- "movt %1 \n\t"
- : "=&z" (__res), "=&r" (__done)
- : "r" (&(count)->counter)
- : "t");
-
- if (unlikely(!__done || __res <= 0))
- fail_fn(count);
-}
-
-/*
- * If the unlock was done on a contended lock, or if the unlock simply fails
- * then the mutex remains locked.
- */
-#define __mutex_slowpath_needs_to_unlock() 1
-
-/*
- * For __mutex_fastpath_trylock we do an atomic decrement and check the
- * result and put it in the __res variable.
- */
-static inline int
-__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
-{
- int __res, __orig;
-
- __asm__ __volatile__ (
- "1: movli.l @%2, %0 \n\t"
- "dt %0 \n\t"
- "movco.l %0,@%2 \n\t"
- "bf 1b \n\t"
- "cmp/eq #0,%0 \n\t"
- "bt 2f \n\t"
- "mov #0, %1 \n\t"
- "bf 3f \n\t"
- "2: mov #1, %1 \n\t"
- "3: "
- : "=&z" (__orig), "=&r" (__res)
- : "r" (&count->counter)
- : "t");
-
- return __res;
-}
-#endif /* __ASM_SH_MUTEX_LLSC_H */
diff --git a/arch/sh/include/asm/mutex.h b/arch/sh/include/asm/mutex.h
deleted file mode 100644
index d8e37716a4a0..000000000000
--- a/arch/sh/include/asm/mutex.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-#if defined(CONFIG_CPU_SH4A)
-#include <asm/mutex-llsc.h>
-#else
-#include <asm-generic/mutex-dec.h>
-#endif
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index 6024c26c0585..de90e6a10b2b 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -14,7 +14,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
-generic-y += mutex.h
generic-y += preempt.h
generic-y += rwsem.h
generic-y += serial.h
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index ba35c41c71ff..2d1f5638974c 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -21,7 +21,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += msgbuf.h
-generic-y += mutex.h
generic-y += param.h
generic-y += parport.h
generic-y += poll.h
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 904f3ebf4220..052f7f6d0551 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -17,7 +17,6 @@ generic-y += irq_work.h
generic-y += kdebug.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
-generic-y += mutex.h
generic-y += param.h
generic-y += pci.h
generic-y += percpu.h
diff --git a/arch/unicore32/include/asm/mutex.h b/arch/unicore32/include/asm/mutex.h
deleted file mode 100644
index fab7d0e8adf6..000000000000
--- a/arch/unicore32/include/asm/mutex.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * linux/arch/unicore32/include/asm/mutex.h
- *
- * Code specific to PKUnity SoC and UniCore ISA
- *
- * Copyright (C) 2001-2010 GUAN Xue-tao
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * UniCore optimized mutex locking primitives
- *
- * Please look into asm-generic/mutex-xchg.h for a formal definition.
- */
-#ifndef __UNICORE_MUTEX_H__
-#define __UNICORE_MUTEX_H__
-
-# include <asm-generic/mutex-xchg.h>
-#endif
diff --git a/arch/x86/include/asm/mutex.h b/arch/x86/include/asm/mutex.h
deleted file mode 100644
index 7d3a48275394..000000000000
--- a/arch/x86/include/asm/mutex.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#ifdef CONFIG_X86_32
-# include <asm/mutex_32.h>
-#else
-# include <asm/mutex_64.h>
-#endif
diff --git a/arch/x86/include/asm/mutex_32.h b/arch/x86/include/asm/mutex_32.h
deleted file mode 100644
index e9355a84fc67..000000000000
--- a/arch/x86/include/asm/mutex_32.h
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * Assembly implementation of the mutex fastpath, based on atomic
- * decrement/increment.
- *
- * started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@...hat.com>
- */
-#ifndef _ASM_X86_MUTEX_32_H
-#define _ASM_X86_MUTEX_32_H
-
-#include <asm/alternative.h>
-
-/**
- * __mutex_fastpath_lock - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- * @fn: function to call if the original value was not 1
- *
- * Change the count from 1 to a value lower than 1, and call <fn> if it
- * wasn't 1 originally. This function MUST leave the value lower than 1
- * even when the "1" assertion wasn't true.
- */
-#define __mutex_fastpath_lock(count, fail_fn) \
-do { \
- unsigned int dummy; \
- \
- typecheck(atomic_t *, count); \
- typecheck_fn(void (*)(atomic_t *), fail_fn); \
- \
- asm volatile(LOCK_PREFIX " decl (%%eax)\n" \
- " jns 1f \n" \
- " call " #fail_fn "\n" \
- "1:\n" \
- : "=a" (dummy) \
- : "a" (count) \
- : "memory", "ecx", "edx"); \
-} while (0)
-
-
-/**
- * __mutex_fastpath_lock_retval - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- *
- * Change the count from 1 to a value lower than 1. This function returns 0
- * if the fastpath succeeds, or -1 otherwise.
- */
-static inline int __mutex_fastpath_lock_retval(atomic_t *count)
-{
- if (unlikely(atomic_dec_return(count) < 0))
- return -1;
- else
- return 0;
-}
-
-/**
- * __mutex_fastpath_unlock - try to promote the mutex from 0 to 1
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 0
- *
- * try to promote the mutex from 0 to 1. if it wasn't 0, call <fail_fn>.
- * In the failure case, this function is allowed to either set the value
- * to 1, or to set it to a value lower than 1.
- *
- * If the implementation sets it to a value of lower than 1, the
- * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
- * to return 0 otherwise.
- */
-#define __mutex_fastpath_unlock(count, fail_fn) \
-do { \
- unsigned int dummy; \
- \
- typecheck(atomic_t *, count); \
- typecheck_fn(void (*)(atomic_t *), fail_fn); \
- \
- asm volatile(LOCK_PREFIX " incl (%%eax)\n" \
- " jg 1f\n" \
- " call " #fail_fn "\n" \
- "1:\n" \
- : "=a" (dummy) \
- : "a" (count) \
- : "memory", "ecx", "edx"); \
-} while (0)
-
-#define __mutex_slowpath_needs_to_unlock() 1
-
-/**
- * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
- *
- * @count: pointer of type atomic_t
- * @fail_fn: fallback function
- *
- * Change the count from 1 to a value lower than 1, and return 0 (failure)
- * if it wasn't 1 originally, or return 1 (success) otherwise. This function
- * MUST leave the value lower than 1 even when the "1" assertion wasn't true.
- * Additionally, if the value was < 0 originally, this function must not leave
- * it to 0 on failure.
- */
-static inline int __mutex_fastpath_trylock(atomic_t *count,
- int (*fail_fn)(atomic_t *))
-{
- /* cmpxchg because it never induces a false contention state. */
- if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
- return 1;
-
- return 0;
-}
-
-#endif /* _ASM_X86_MUTEX_32_H */
diff --git a/arch/x86/include/asm/mutex_64.h b/arch/x86/include/asm/mutex_64.h
deleted file mode 100644
index d9850758464e..000000000000
--- a/arch/x86/include/asm/mutex_64.h
+++ /dev/null
@@ -1,127 +0,0 @@
-/*
- * Assembly implementation of the mutex fastpath, based on atomic
- * decrement/increment.
- *
- * started by Ingo Molnar:
- *
- * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@...hat.com>
- */
-#ifndef _ASM_X86_MUTEX_64_H
-#define _ASM_X86_MUTEX_64_H
-
-/**
- * __mutex_fastpath_lock - decrement and call function if negative
- * @v: pointer of type atomic_t
- * @fail_fn: function to call if the result is negative
- *
- * Atomically decrements @v and calls <fail_fn> if the result is negative.
- */
-#ifdef CC_HAVE_ASM_GOTO
-static inline void __mutex_fastpath_lock(atomic_t *v,
- void (*fail_fn)(atomic_t *))
-{
- asm_volatile_goto(LOCK_PREFIX " decl %0\n"
- " jns %l[exit]\n"
- : : "m" (v->counter)
- : "memory", "cc"
- : exit);
- fail_fn(v);
-exit:
- return;
-}
-#else
-#define __mutex_fastpath_lock(v, fail_fn) \
-do { \
- unsigned long dummy; \
- \
- typecheck(atomic_t *, v); \
- typecheck_fn(void (*)(atomic_t *), fail_fn); \
- \
- asm volatile(LOCK_PREFIX " decl (%%rdi)\n" \
- " jns 1f \n" \
- " call " #fail_fn "\n" \
- "1:" \
- : "=D" (dummy) \
- : "D" (v) \
- : "rax", "rsi", "rdx", "rcx", \
- "r8", "r9", "r10", "r11", "memory"); \
-} while (0)
-#endif
-
-/**
- * __mutex_fastpath_lock_retval - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- *
- * Change the count from 1 to a value lower than 1. This function returns 0
- * if the fastpath succeeds, or -1 otherwise.
- */
-static inline int __mutex_fastpath_lock_retval(atomic_t *count)
-{
- if (unlikely(atomic_dec_return(count) < 0))
- return -1;
- else
- return 0;
-}
-
-/**
- * __mutex_fastpath_unlock - increment and call function if nonpositive
- * @v: pointer of type atomic_t
- * @fail_fn: function to call if the result is nonpositive
- *
- * Atomically increments @v and calls <fail_fn> if the result is nonpositive.
- */
-#ifdef CC_HAVE_ASM_GOTO
-static inline void __mutex_fastpath_unlock(atomic_t *v,
- void (*fail_fn)(atomic_t *))
-{
- asm_volatile_goto(LOCK_PREFIX " incl %0\n"
- " jg %l[exit]\n"
- : : "m" (v->counter)
- : "memory", "cc"
- : exit);
- fail_fn(v);
-exit:
- return;
-}
-#else
-#define __mutex_fastpath_unlock(v, fail_fn) \
-do { \
- unsigned long dummy; \
- \
- typecheck(atomic_t *, v); \
- typecheck_fn(void (*)(atomic_t *), fail_fn); \
- \
- asm volatile(LOCK_PREFIX " incl (%%rdi)\n" \
- " jg 1f\n" \
- " call " #fail_fn "\n" \
- "1:" \
- : "=D" (dummy) \
- : "D" (v) \
- : "rax", "rsi", "rdx", "rcx", \
- "r8", "r9", "r10", "r11", "memory"); \
-} while (0)
-#endif
-
-#define __mutex_slowpath_needs_to_unlock() 1
-
-/**
- * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
- *
- * @count: pointer of type atomic_t
- * @fail_fn: fallback function
- *
- * Change the count from 1 to 0 and return 1 (success), or return 0 (failure)
- * if it wasn't 1 originally. [the fallback function is never used on
- * x86_64, because all x86_64 CPUs have a CMPXCHG instruction.]
- */
-static inline int __mutex_fastpath_trylock(atomic_t *count,
- int (*fail_fn)(atomic_t *))
-{
- if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
- return 1;
-
- return 0;
-}
-
-#endif /* _ASM_X86_MUTEX_64_H */
diff --git a/arch/xtensa/include/asm/mutex.h b/arch/xtensa/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/xtensa/include/asm/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Pull in the generic implementation for the mutex fastpath.
- *
- * TODO: implement optimized primitives instead, or leave the generic
- * implementation in place, or pick the atomic_xchg() based generic
- * implementation. (see asm-generic/mutex-xchg.h for details)
- */
-
-#include <asm-generic/mutex-dec.h>
diff --git a/include/asm-generic/mutex-dec.h b/include/asm-generic/mutex-dec.h
deleted file mode 100644
index c54829d3de37..000000000000
--- a/include/asm-generic/mutex-dec.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
- * include/asm-generic/mutex-dec.h
- *
- * Generic implementation of the mutex fastpath, based on atomic
- * decrement/increment.
- */
-#ifndef _ASM_GENERIC_MUTEX_DEC_H
-#define _ASM_GENERIC_MUTEX_DEC_H
-
-/**
- * __mutex_fastpath_lock - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 1
- *
- * Change the count from 1 to a value lower than 1, and call <fail_fn> if
- * it wasn't 1 originally. This function MUST leave the value lower than
- * 1 even when the "1" assertion wasn't true.
- */
-static inline void
-__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(atomic_dec_return_acquire(count) < 0))
- fail_fn(count);
-}
-
-/**
- * __mutex_fastpath_lock_retval - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- *
- * Change the count from 1 to a value lower than 1. This function returns 0
- * if the fastpath succeeds, or -1 otherwise.
- */
-static inline int
-__mutex_fastpath_lock_retval(atomic_t *count)
-{
- if (unlikely(atomic_dec_return_acquire(count) < 0))
- return -1;
- return 0;
-}
-
-/**
- * __mutex_fastpath_unlock - try to promote the count from 0 to 1
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 0
- *
- * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
- * In the failure case, this function is allowed to either set the value to
- * 1, or to set it to a value lower than 1.
- *
- * If the implementation sets it to a value of lower than 1, then the
- * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
- * to return 0 otherwise.
- */
-static inline void
-__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(atomic_inc_return_release(count) <= 0))
- fail_fn(count);
-}
-
-#define __mutex_slowpath_needs_to_unlock() 1
-
-/**
- * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
- *
- * @count: pointer of type atomic_t
- * @fail_fn: fallback function
- *
- * Change the count from 1 to a value lower than 1, and return 0 (failure)
- * if it wasn't 1 originally, or return 1 (success) otherwise. This function
- * MUST leave the value lower than 1 even when the "1" assertion wasn't true.
- * Additionally, if the value was < 0 originally, this function must not leave
- * it to 0 on failure.
- *
- * If the architecture has no effective trylock variant, it should call the
- * <fail_fn> spinlock-based trylock variant unconditionally.
- */
-static inline int
-__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
-{
- if (likely(atomic_read(count) == 1 && atomic_cmpxchg_acquire(count, 1, 0) == 1))
- return 1;
- return 0;
-}
-
-#endif
diff --git a/include/asm-generic/mutex-null.h b/include/asm-generic/mutex-null.h
deleted file mode 100644
index 61069ed334e2..000000000000
--- a/include/asm-generic/mutex-null.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * include/asm-generic/mutex-null.h
- *
- * Generic implementation of the mutex fastpath, based on NOP :-)
- *
- * This is used by the mutex-debugging infrastructure, but it can also
- * be used by architectures that (for whatever reason) want to use the
- * spinlock based slowpath.
- */
-#ifndef _ASM_GENERIC_MUTEX_NULL_H
-#define _ASM_GENERIC_MUTEX_NULL_H
-
-#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count)
-#define __mutex_fastpath_lock_retval(count) (-1)
-#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count)
-#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
-#define __mutex_slowpath_needs_to_unlock() 1
-
-#endif
diff --git a/include/asm-generic/mutex-xchg.h b/include/asm-generic/mutex-xchg.h
deleted file mode 100644
index 3269ec4e195f..000000000000
--- a/include/asm-generic/mutex-xchg.h
+++ /dev/null
@@ -1,120 +0,0 @@
-/*
- * include/asm-generic/mutex-xchg.h
- *
- * Generic implementation of the mutex fastpath, based on xchg().
- *
- * NOTE: An xchg based implementation might be less optimal than an atomic
- * decrement/increment based implementation. If your architecture
- * has a reasonable atomic dec/inc then you should probably use
- * asm-generic/mutex-dec.h instead, or you could open-code an
- * optimized version in asm/mutex.h.
- */
-#ifndef _ASM_GENERIC_MUTEX_XCHG_H
-#define _ASM_GENERIC_MUTEX_XCHG_H
-
-/**
- * __mutex_fastpath_lock - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 1
- *
- * Change the count from 1 to a value lower than 1, and call <fail_fn> if it
- * wasn't 1 originally. This function MUST leave the value lower than 1
- * even when the "1" assertion wasn't true.
- */
-static inline void
-__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(atomic_xchg(count, 0) != 1))
- /*
- * We failed to acquire the lock, so mark it contended
- * to ensure that any waiting tasks are woken up by the
- * unlock slow path.
- */
- if (likely(atomic_xchg_acquire(count, -1) != 1))
- fail_fn(count);
-}
-
-/**
- * __mutex_fastpath_lock_retval - try to take the lock by moving the count
- * from 1 to a 0 value
- * @count: pointer of type atomic_t
- *
- * Change the count from 1 to a value lower than 1. This function returns 0
- * if the fastpath succeeds, or -1 otherwise.
- */
-static inline int
-__mutex_fastpath_lock_retval(atomic_t *count)
-{
- if (unlikely(atomic_xchg_acquire(count, 0) != 1))
- if (likely(atomic_xchg(count, -1) != 1))
- return -1;
- return 0;
-}
-
-/**
- * __mutex_fastpath_unlock - try to promote the mutex from 0 to 1
- * @count: pointer of type atomic_t
- * @fail_fn: function to call if the original value was not 0
- *
- * try to promote the mutex from 0 to 1. if it wasn't 0, call <function>
- * In the failure case, this function is allowed to either set the value to
- * 1, or to set it to a value lower than one.
- * If the implementation sets it to a value of lower than one, the
- * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
- * to return 0 otherwise.
- */
-static inline void
-__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
-{
- if (unlikely(atomic_xchg_release(count, 1) != 0))
- fail_fn(count);
-}
-
-#define __mutex_slowpath_needs_to_unlock() 0
-
-/**
- * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
- *
- * @count: pointer of type atomic_t
- * @fail_fn: spinlock based trylock implementation
- *
- * Change the count from 1 to a value lower than 1, and return 0 (failure)
- * if it wasn't 1 originally, or return 1 (success) otherwise. This function
- * MUST leave the value lower than 1 even when the "1" assertion wasn't true.
- * Additionally, if the value was < 0 originally, this function must not leave
- * it to 0 on failure.
- *
- * If the architecture has no effective trylock variant, it should call the
- * <fail_fn> spinlock-based trylock variant unconditionally.
- */
-static inline int
-__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
-{
- int prev;
-
- if (atomic_read(count) != 1)
- return 0;
-
- prev = atomic_xchg_acquire(count, 0);
- if (unlikely(prev < 0)) {
- /*
- * The lock was marked contended so we must restore that
- * state. If while doing so we get back a prev value of 1
- * then we just own it.
- *
- * [ In the rare case of the mutex going to 1, to 0, to -1
- * and then back to 0 in this few-instructions window,
- * this has the potential to trigger the slowpath for the
- * owner's unlock path needlessly, but that's not a problem
- * in practice. ]
- */
- prev = atomic_xchg_acquire(count, prev);
- if (prev < 0)
- prev = 0;
- }
-
- return prev;
-}
-
-#endif
diff --git a/include/asm-generic/mutex.h b/include/asm-generic/mutex.h
deleted file mode 100644
index fe91ab502793..000000000000
--- a/include/asm-generic/mutex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#ifndef __ASM_GENERIC_MUTEX_H
-#define __ASM_GENERIC_MUTEX_H
-/*
- * Pull in the generic implementation for the mutex fastpath,
- * which is a reasonable default on many architectures.
- */
-
-#include <asm-generic/mutex-dec.h>
-#endif /* __ASM_GENERIC_MUTEX_H */
diff --git a/include/linux/mutex-debug.h b/include/linux/mutex-debug.h
deleted file mode 100644
index 4ac8b1977b73..000000000000
--- a/include/linux/mutex-debug.h
+++ /dev/null
@@ -1,24 +0,0 @@
-#ifndef __LINUX_MUTEX_DEBUG_H
-#define __LINUX_MUTEX_DEBUG_H
-
-#include <linux/linkage.h>
-#include <linux/lockdep.h>
-#include <linux/debug_locks.h>
-
-/*
- * Mutexes - debugging helpers:
- */
-
-#define __DEBUG_MUTEX_INITIALIZER(lockname) \
- , .magic = &lockname
-
-#define mutex_init(mutex) \
-do { \
- static struct lock_class_key __key; \
- \
- __mutex_init((mutex), #mutex, &__key); \
-} while (0)
-
-extern void mutex_destroy(struct mutex *lock);
-
-#endif
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 2cb7531e7d7a..4d3bccabbea5 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -18,6 +18,7 @@
#include <linux/atomic.h>
#include <asm/processor.h>
#include <linux/osq_lock.h>
+#include <linux/debug_locks.h>
/*
* Simple, straightforward mutexes with strict semantics:
@@ -48,16 +49,12 @@
* locks and tasks (and only those tasks)
*/
struct mutex {
- /* 1: unlocked, 0: locked, negative: locked, possible waiters */
- atomic_t count;
+ atomic_long_t owner;
spinlock_t wait_lock;
- struct list_head wait_list;
-#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER)
- struct task_struct *owner;
-#endif
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
struct optimistic_spin_queue osq; /* Spinner MCS lock */
#endif
+ struct list_head wait_list;
#ifdef CONFIG_DEBUG_MUTEXES
void *magic;
#endif
@@ -66,6 +63,11 @@ struct mutex {
#endif
};
+static inline struct task_struct *__mutex_owner(struct mutex *lock)
+{
+ return (struct task_struct *)(atomic_long_read(&lock->owner) & ~0x03);
+}
+
/*
* This is the control structure for tasks blocked on mutex,
* which resides on the blocked task's kernel stack:
@@ -79,9 +81,20 @@ struct mutex_waiter {
};
#ifdef CONFIG_DEBUG_MUTEXES
-# include <linux/mutex-debug.h>
+
+#define __DEBUG_MUTEX_INITIALIZER(lockname) \
+ , .magic = &lockname
+
+extern void mutex_destroy(struct mutex *lock);
+
#else
+
# define __DEBUG_MUTEX_INITIALIZER(lockname)
+
+static inline void mutex_destroy(struct mutex *lock) {}
+
+#endif
+
/**
* mutex_init - initialize the mutex
* @mutex: the mutex to be initialized
@@ -90,14 +103,12 @@ struct mutex_waiter {
*
* It is not allowed to initialize an already locked mutex.
*/
-# define mutex_init(mutex) \
-do { \
- static struct lock_class_key __key; \
- \
- __mutex_init((mutex), #mutex, &__key); \
+#define mutex_init(mutex) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ __mutex_init((mutex), #mutex, &__key); \
} while (0)
-static inline void mutex_destroy(struct mutex *lock) {}
-#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
@@ -107,7 +118,7 @@ static inline void mutex_destroy(struct mutex *lock) {}
#endif
#define __MUTEX_INITIALIZER(lockname) \
- { .count = ATOMIC_INIT(1) \
+ { .owner = ATOMIC_LONG_INIT(0) \
, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
, .wait_list = LIST_HEAD_INIT(lockname.wait_list) \
__DEBUG_MUTEX_INITIALIZER(lockname) \
@@ -127,7 +138,10 @@ extern void __mutex_init(struct mutex *lock, const char *name,
*/
static inline int mutex_is_locked(struct mutex *lock)
{
- return atomic_read(&lock->count) != 1;
+ /*
+ * XXX think about spin_is_locked
+ */
+ return __mutex_owner(lock) != NULL;
}
/*
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 9c951fade415..9aa713629387 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -73,21 +73,8 @@ void debug_mutex_unlock(struct mutex *lock)
{
if (likely(debug_locks)) {
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
-
- if (!lock->owner)
- DEBUG_LOCKS_WARN_ON(!lock->owner);
- else
- DEBUG_LOCKS_WARN_ON(lock->owner != current);
-
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
}
-
- /*
- * __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug
- * mutexes so that we can do it here after we've verified state.
- */
- mutex_clear_owner(lock);
- atomic_set(&lock->count, 1);
}
void debug_mutex_init(struct mutex *lock, const char *name,
diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h
index 57a871ae3c81..a459faa48987 100644
--- a/kernel/locking/mutex-debug.h
+++ b/kernel/locking/mutex-debug.h
@@ -27,16 +27,6 @@ extern void debug_mutex_unlock(struct mutex *lock);
extern void debug_mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
-static inline void mutex_set_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, current);
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, NULL);
-}
-
#define spin_lock_mutex(lock, flags) \
do { \
struct mutex *l = container_of(lock, struct mutex, wait_lock); \
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index a70b90db3909..d4bff1d7f92a 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -33,35 +33,90 @@
*/
#ifdef CONFIG_DEBUG_MUTEXES
# include "mutex-debug.h"
-# include <asm-generic/mutex-null.h>
-/*
- * Must be 0 for the debug case so we do not do the unlock outside of the
- * wait_lock region. debug_mutex_unlock() will do the actual unlock in this
- * case.
- */
-# undef __mutex_slowpath_needs_to_unlock
-# define __mutex_slowpath_needs_to_unlock() 0
#else
# include "mutex.h"
-# include <asm/mutex.h>
#endif
void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
- atomic_set(&lock->count, 1);
+ atomic_long_set(&lock->owner, 0);
spin_lock_init(&lock->wait_lock);
INIT_LIST_HEAD(&lock->wait_list);
- mutex_clear_owner(lock);
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
osq_lock_init(&lock->osq);
#endif
debug_mutex_init(lock, name, key);
}
-
EXPORT_SYMBOL(__mutex_init);
+#define MUTEX_FLAG_WAITERS 0x01
+
+#define MUTEX_FLAGS 0x03
+
+static inline struct task_struct *__owner_task(unsigned long owner)
+{
+ return (struct task_struct *)(owner & ~MUTEX_FLAGS);
+}
+
+static inline unsigned long __owner_flags(unsigned long owner)
+{
+ return owner & MUTEX_FLAGS;
+}
+
+/*
+ * Actual trylock that will work on any unlocked state.
+ */
+static inline bool __mutex_trylock(struct mutex *lock)
+{
+ unsigned long owner, curr = (unsigned long)current;
+
+ owner = atomic_long_read(&lock->owner);
+ for (;;) { /* must loop, can race against a flag */
+ unsigned long old;
+
+ if (__owner_task(owner)) {
+ if ((unsigned long)__owner_task(owner) == curr)
+ return true;
+
+ return false;
+ }
+
+ curr |= __owner_flags(owner);
+ old = atomic_long_cmpxchg_acquire(&lock->owner, owner, curr);
+ if (old == owner)
+ return true;
+
+ owner = old;
+ }
+}
+
+/*
+ * Optimistic trylock that only works in the uncontended case. Make sure to
+ * follow with a __mutex_trylock() before failing.
+ */
+static __always_inline bool __mutex_trylock_fast(struct mutex *lock)
+{
+ unsigned long owner, curr = (unsigned long)current;
+
+ owner = atomic_long_cmpxchg_acquire(&lock->owner, 0UL, curr);
+ if (!owner)
+ return true;
+
+ return false;
+}
+
+static inline void __mutex_set_flag(struct mutex *lock, unsigned long flag)
+{
+ atomic_long_or(flag, &lock->owner);
+}
+
+static inline void __mutex_clear_flag(struct mutex *lock, unsigned long flag)
+{
+ atomic_long_andnot(flag, &lock->owner);
+}
+
#ifndef CONFIG_DEBUG_LOCK_ALLOC
/*
* We split the mutex lock/unlock logic into separate fastpath and
@@ -69,7 +124,7 @@ EXPORT_SYMBOL(__mutex_init);
* We also put the fastpath first in the kernel image, to make sure the
* branch is predicted by the CPU as default-untaken.
*/
-__visible void __sched __mutex_lock_slowpath(atomic_t *lock_count);
+static void __sched __mutex_lock_slowpath(struct mutex *lock);
/**
* mutex_lock - acquire the mutex
@@ -95,14 +150,10 @@ __visible void __sched __mutex_lock_slowpath(atomic_t *lock_count);
void __sched mutex_lock(struct mutex *lock)
{
might_sleep();
- /*
- * The locking fastpath is the 1->0 transition from
- * 'unlocked' into 'locked' state.
- */
- __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
- mutex_set_owner(lock);
-}
+ if (!__mutex_trylock_fast(lock))
+ __mutex_lock_slowpath(lock);
+}
EXPORT_SYMBOL(mutex_lock);
#endif
@@ -176,7 +227,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock,
/*
* Check if lock is contended, if not there is nobody to wake up
*/
- if (likely(atomic_read(&lock->base.count) == 0))
+ if (likely(!(atomic_long_read(&lock->base.owner) & MUTEX_FLAG_WAITERS)))
return;
/*
@@ -227,7 +278,7 @@ bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
bool ret = true;
rcu_read_lock();
- while (lock->owner == owner) {
+ while (__mutex_owner(lock) == owner) {
/*
* Ensure we emit the owner->on_cpu, dereference _after_
* checking lock->owner still matches owner. If that fails,
@@ -260,7 +311,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
return 0;
rcu_read_lock();
- owner = READ_ONCE(lock->owner);
+ owner = __mutex_owner(lock);
if (owner)
retval = owner->on_cpu;
rcu_read_unlock();
@@ -272,15 +323,6 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
}
/*
- * Atomically try to take the lock when it is available
- */
-static inline bool mutex_try_to_acquire(struct mutex *lock)
-{
- return !mutex_is_locked(lock) &&
- (atomic_cmpxchg_acquire(&lock->count, 1, 0) == 1);
-}
-
-/*
* Optimistic spinning.
*
* We try to spin for acquisition when we find that the lock owner
@@ -342,12 +384,12 @@ static bool mutex_optimistic_spin(struct mutex *lock,
* If there's an owner, wait for it to either
* release the lock or go to sleep.
*/
- owner = READ_ONCE(lock->owner);
+ owner = __mutex_owner(lock);
if (owner && !mutex_spin_on_owner(lock, owner))
break;
/* Try to acquire the mutex if it is unlocked. */
- if (mutex_try_to_acquire(lock)) {
+ if (__mutex_trylock(lock)) {
lock_acquired(&lock->dep_map, ip);
if (use_ww_ctx) {
@@ -357,7 +399,6 @@ static bool mutex_optimistic_spin(struct mutex *lock,
ww_mutex_set_context_fastpath(ww, ww_ctx);
}
- mutex_set_owner(lock);
osq_unlock(&lock->osq);
return true;
}
@@ -406,8 +447,7 @@ static bool mutex_optimistic_spin(struct mutex *lock,
}
#endif
-__visible __used noinline
-void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
+static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock);
/**
* mutex_unlock - release the mutex
@@ -422,21 +462,16 @@ void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
*/
void __sched mutex_unlock(struct mutex *lock)
{
- /*
- * The unlocking fastpath is the 0->1 transition from 'locked'
- * into 'unlocked' state:
- */
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(lock);
+ unsigned long owner;
+
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(__mutex_owner(lock) != current);
#endif
- __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
-}
+ owner = atomic_long_fetch_and(MUTEX_FLAGS, &lock->owner);
+ if (__owner_flags(owner))
+ __mutex_unlock_slowpath(lock);
+}
EXPORT_SYMBOL(mutex_unlock);
/**
@@ -465,15 +500,7 @@ void __sched ww_mutex_unlock(struct ww_mutex *lock)
lock->ctx = NULL;
}
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(&lock->base);
-#endif
- __mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
+ mutex_unlock(&lock->base);
}
EXPORT_SYMBOL(ww_mutex_unlock);
@@ -520,7 +547,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
preempt_disable();
mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
- if (mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx)) {
+ if (__mutex_trylock(lock) || mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx)) {
/* got the lock, yay! */
preempt_enable();
return 0;
@@ -529,11 +556,9 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
spin_lock_mutex(&lock->wait_lock, flags);
/*
- * Once more, try to acquire the lock. Only try-lock the mutex if
- * it is unlocked to reduce unnecessary xchg() operations.
+ * Once more, try to acquire the lock.
*/
- if (!mutex_is_locked(lock) &&
- (atomic_xchg_acquire(&lock->count, 0) == 1))
+ if (__mutex_trylock(lock))
goto skip_wait;
debug_mutex_lock_common(lock, &waiter);
@@ -543,21 +568,20 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
list_add_tail(&waiter.list, &lock->wait_list);
waiter.task = task;
+ if (list_first_entry(&lock->wait_list, struct mutex_waiter, list) == &waiter) {
+ __mutex_set_flag(lock, MUTEX_FLAG_WAITERS);
+ /*
+ * We must be sure to set WAITERS before attempting the trylock
+ * below, such that mutex_unlock() must either see our WAITERS
+ * or we see its unlock.
+ */
+ smp_mb__after_atomic();
+ }
+
lock_contended(&lock->dep_map, ip);
for (;;) {
- /*
- * Lets try to take the lock again - this is needed even if
- * we get here for the first time (shortly after failing to
- * acquire the lock), to make sure that we get a wakeup once
- * it's unlocked. Later on, if we sleep, this is the
- * operation that gives us the lock. We xchg it to -1, so
- * that when we release the lock, we properly wake up the
- * other waiters. We only attempt the xchg if the count is
- * non-negative in order to avoid unnecessary xchg operations:
- */
- if (atomic_read(&lock->count) >= 0 &&
- (atomic_xchg_acquire(&lock->count, -1) == 1))
+ if (__mutex_trylock(lock))
break;
/*
@@ -587,13 +611,13 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
mutex_remove_waiter(lock, &waiter, task);
/* set it to 0 if there are no waiters left: */
if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
+ __mutex_clear_flag(lock, MUTEX_FLAG_WAITERS);
+
debug_mutex_free_waiter(&waiter);
skip_wait:
/* got the lock - cleanup and rejoice! */
lock_acquired(&lock->dep_map, ip);
- mutex_set_owner(lock);
if (use_ww_ctx) {
struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
@@ -631,7 +655,6 @@ _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
0, nest, _RET_IP_, NULL, 0);
}
-
EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
int __sched
@@ -650,7 +673,6 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
subclass, NULL, _RET_IP_, NULL, 0);
}
-
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
static inline int
@@ -715,29 +737,13 @@ EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
/*
* Release the lock, slowpath:
*/
-static inline void
-__mutex_unlock_common_slowpath(struct mutex *lock, int nested)
+static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock)
{
unsigned long flags;
WAKE_Q(wake_q);
- /*
- * As a performance measurement, release the lock before doing other
- * wakeup related duties to follow. This allows other tasks to acquire
- * the lock sooner, while still handling cleanups in past unlock calls.
- * This can be done as we do not enforce strict equivalence between the
- * mutex counter and wait_list.
- *
- *
- * Some architectures leave the lock unlocked in the fastpath failure
- * case, others need to leave it locked. In the later case we have to
- * unlock it here - as the lock counter is currently 0 or negative.
- */
- if (__mutex_slowpath_needs_to_unlock())
- atomic_set(&lock->count, 1);
-
spin_lock_mutex(&lock->wait_lock, flags);
- mutex_release(&lock->dep_map, nested, _RET_IP_);
+ mutex_release(&lock->dep_map, 0, _RET_IP_);
debug_mutex_unlock(lock);
if (!list_empty(&lock->wait_list)) {
@@ -754,17 +760,6 @@ __mutex_unlock_common_slowpath(struct mutex *lock, int nested)
wake_up_q(&wake_q);
}
-/*
- * Release the lock, slowpath:
- */
-__visible void
-__mutex_unlock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
-
- __mutex_unlock_common_slowpath(lock, 1);
-}
-
#ifndef CONFIG_DEBUG_LOCK_ALLOC
/*
* Here come the less common (and hence less performance-critical) APIs:
@@ -789,38 +784,29 @@ __mutex_lock_interruptible_slowpath(struct mutex *lock);
*/
int __sched mutex_lock_interruptible(struct mutex *lock)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
+
+ if (__mutex_trylock_fast(lock))
return 0;
- } else
- return __mutex_lock_interruptible_slowpath(lock);
+
+ return __mutex_lock_interruptible_slowpath(lock);
}
EXPORT_SYMBOL(mutex_lock_interruptible);
int __sched mutex_lock_killable(struct mutex *lock)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
+
+ if (__mutex_trylock_fast(lock))
return 0;
- } else
- return __mutex_lock_killable_slowpath(lock);
+
+ return __mutex_lock_killable_slowpath(lock);
}
EXPORT_SYMBOL(mutex_lock_killable);
-__visible void __sched
-__mutex_lock_slowpath(atomic_t *lock_count)
+static void __sched __mutex_lock_slowpath(struct mutex *lock)
{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
-
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
NULL, _RET_IP_, NULL, 0);
}
@@ -856,37 +842,6 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
#endif
-/*
- * Spinlock based trylock, we take the spinlock and check whether we
- * can get the lock:
- */
-static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
- unsigned long flags;
- int prev;
-
- /* No need to trylock if the mutex is locked. */
- if (mutex_is_locked(lock))
- return 0;
-
- spin_lock_mutex(&lock->wait_lock, flags);
-
- prev = atomic_xchg_acquire(&lock->count, -1);
- if (likely(prev == 1)) {
- mutex_set_owner(lock);
- mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- }
-
- /* Set it back to 0 if there are no waiters: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
-
- spin_unlock_mutex(&lock->wait_lock, flags);
-
- return prev == 1;
-}
-
/**
* mutex_trylock - try to acquire the mutex, without waiting
* @lock: the mutex to be acquired
@@ -903,13 +858,7 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
*/
int __sched mutex_trylock(struct mutex *lock)
{
- int ret;
-
- ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
- if (ret)
- mutex_set_owner(lock);
-
- return ret;
+ return __mutex_trylock(lock);
}
EXPORT_SYMBOL(mutex_trylock);
@@ -917,36 +866,28 @@ EXPORT_SYMBOL(mutex_trylock);
int __sched
__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
+ if (__mutex_trylock_fast(&lock->base)) {
ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_slowpath(lock, ctx);
- return ret;
+ return 0;
+ }
+
+ return __ww_mutex_lock_slowpath(lock, ctx);
}
EXPORT_SYMBOL(__ww_mutex_lock);
int __sched
__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
+ if (__mutex_trylock_fast(&lock->base)) {
ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
- return ret;
+ return 0;
+ }
+
+ return __ww_mutex_lock_interruptible_slowpath(lock, ctx);
}
EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
index 6cd6b8e9efd7..4410a4af42a3 100644
--- a/kernel/locking/mutex.h
+++ b/kernel/locking/mutex.h
@@ -16,32 +16,6 @@
#define mutex_remove_waiter(lock, waiter, task) \
__list_del((waiter)->list.prev, (waiter)->list.next)
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-/*
- * The mutex owner can get read and written to locklessly.
- * We should use WRITE_ONCE when writing the owner value to
- * avoid store tearing, otherwise, a thread could potentially
- * read a partially written and incomplete owner value.
- */
-static inline void mutex_set_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, current);
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, NULL);
-}
-#else
-static inline void mutex_set_owner(struct mutex *lock)
-{
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
-}
-#endif
-
#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
#define debug_mutex_free_waiter(waiter) do { } while (0)
#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 69243142cad1..0154b10ea614 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -75,11 +75,11 @@
#include <linux/compiler.h>
#include <linux/frame.h>
#include <linux/prefetch.h>
+#include <linux/mutex.h>
#include <asm/switch_to.h>
#include <asm/tlb.h>
#include <asm/irq_regs.h>
-#include <asm/mutex.h>
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#endif
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