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authorIngo Molnar <mingo@elte.hu>2005-09-10 03:25:56 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-10 13:06:21 -0400
commitfb1c8f93d869b34cacb8b8932e2b83d96a19d720 (patch)
treea006d078aa02e421a7dc4793c335308204859d36 /arch/alpha
parent4327edf6b8a7ac7dce144313947995538842d8fd (diff)
[PATCH] spinlock consolidation
This patch (written by me and also containing many suggestions of Arjan van de Ven) does a major cleanup of the spinlock code. It does the following things: - consolidates and enhances the spinlock/rwlock debugging code - simplifies the asm/spinlock.h files - encapsulates the raw spinlock type and moves generic spinlock features (such as ->break_lock) into the generic code. - cleans up the spinlock code hierarchy to get rid of the spaghetti. Most notably there's now only a single variant of the debugging code, located in lib/spinlock_debug.c. (previously we had one SMP debugging variant per architecture, plus a separate generic one for UP builds) Also, i've enhanced the rwlock debugging facility, it will now track write-owners. There is new spinlock-owner/CPU-tracking on SMP builds too. All locks have lockup detection now, which will work for both soft and hard spin/rwlock lockups. The arch-level include files now only contain the minimally necessary subset of the spinlock code - all the rest that can be generalized now lives in the generic headers: include/asm-i386/spinlock_types.h | 16 include/asm-x86_64/spinlock_types.h | 16 I have also split up the various spinlock variants into separate files, making it easier to see which does what. The new layout is: SMP | UP ----------------------------|----------------------------------- asm/spinlock_types_smp.h | linux/spinlock_types_up.h linux/spinlock_types.h | linux/spinlock_types.h asm/spinlock_smp.h | linux/spinlock_up.h linux/spinlock_api_smp.h | linux/spinlock_api_up.h linux/spinlock.h | linux/spinlock.h /* * here's the role of the various spinlock/rwlock related include files: * * on SMP builds: * * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the * initializers * * linux/spinlock_types.h: * defines the generic type and initializers * * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel * implementations, mostly inline assembly code * * (also included on UP-debug builds:) * * linux/spinlock_api_smp.h: * contains the prototypes for the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. * * on UP builds: * * linux/spinlock_type_up.h: * contains the generic, simplified UP spinlock type. * (which is an empty structure on non-debug builds) * * linux/spinlock_types.h: * defines the generic type and initializers * * linux/spinlock_up.h: * contains the __raw_spin_*()/etc. version of UP * builds. (which are NOPs on non-debug, non-preempt * builds) * * (included on UP-non-debug builds:) * * linux/spinlock_api_up.h: * builds the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. */ All SMP and UP architectures are converted by this patch. arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via crosscompilers. m32r, mips, sh, sparc, have not been tested yet, but should be mostly fine. From: Grant Grundler <grundler@parisc-linux.org> Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU). Builds 32-bit SMP kernel (not booted or tested). I did not try to build non-SMP kernels. That should be trivial to fix up later if necessary. I converted bit ops atomic_hash lock to raw_spinlock_t. Doing so avoids some ugly nesting of linux/*.h and asm/*.h files. Those particular locks are well tested and contained entirely inside arch specific code. I do NOT expect any new issues to arise with them. If someone does ever need to use debug/metrics with them, then they will need to unravel this hairball between spinlocks, atomic ops, and bit ops that exist only because parisc has exactly one atomic instruction: LDCW (load and clear word). From: "Luck, Tony" <tony.luck@intel.com> ia64 fix Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjanv@infradead.org> Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se> Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/alpha')
-rw-r--r--arch/alpha/kernel/alpha_ksyms.c9
-rw-r--r--arch/alpha/kernel/smp.c172
2 files changed, 0 insertions, 181 deletions
diff --git a/arch/alpha/kernel/alpha_ksyms.c b/arch/alpha/kernel/alpha_ksyms.c
index fc5ef90c4fc9..24ae9a366073 100644
--- a/arch/alpha/kernel/alpha_ksyms.c
+++ b/arch/alpha/kernel/alpha_ksyms.c
@@ -185,15 +185,6 @@ EXPORT_SYMBOL(smp_num_cpus);
185EXPORT_SYMBOL(smp_call_function); 185EXPORT_SYMBOL(smp_call_function);
186EXPORT_SYMBOL(smp_call_function_on_cpu); 186EXPORT_SYMBOL(smp_call_function_on_cpu);
187EXPORT_SYMBOL(_atomic_dec_and_lock); 187EXPORT_SYMBOL(_atomic_dec_and_lock);
188#ifdef CONFIG_DEBUG_SPINLOCK
189EXPORT_SYMBOL(_raw_spin_unlock);
190EXPORT_SYMBOL(debug_spin_lock);
191EXPORT_SYMBOL(debug_spin_trylock);
192#endif
193#ifdef CONFIG_DEBUG_RWLOCK
194EXPORT_SYMBOL(_raw_write_lock);
195EXPORT_SYMBOL(_raw_read_lock);
196#endif
197EXPORT_SYMBOL(cpu_present_mask); 188EXPORT_SYMBOL(cpu_present_mask);
198#endif /* CONFIG_SMP */ 189#endif /* CONFIG_SMP */
199 190
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index e211aa7404e6..da0be3465791 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -989,175 +989,3 @@ flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
989 989
990 preempt_enable(); 990 preempt_enable();
991} 991}
992
993#ifdef CONFIG_DEBUG_SPINLOCK
994void
995_raw_spin_unlock(spinlock_t * lock)
996{
997 mb();
998 lock->lock = 0;
999
1000 lock->on_cpu = -1;
1001 lock->previous = NULL;
1002 lock->task = NULL;
1003 lock->base_file = "none";
1004 lock->line_no = 0;
1005}
1006
1007void
1008debug_spin_lock(spinlock_t * lock, const char *base_file, int line_no)
1009{
1010 long tmp;
1011 long stuck;
1012 void *inline_pc = __builtin_return_address(0);
1013 unsigned long started = jiffies;
1014 int printed = 0;
1015 int cpu = smp_processor_id();
1016
1017 stuck = 1L << 30;
1018 try_again:
1019
1020 /* Use sub-sections to put the actual loop at the end
1021 of this object file's text section so as to perfect
1022 branch prediction. */
1023 __asm__ __volatile__(
1024 "1: ldl_l %0,%1\n"
1025 " subq %2,1,%2\n"
1026 " blbs %0,2f\n"
1027 " or %0,1,%0\n"
1028 " stl_c %0,%1\n"
1029 " beq %0,3f\n"
1030 "4: mb\n"
1031 ".subsection 2\n"
1032 "2: ldl %0,%1\n"
1033 " subq %2,1,%2\n"
1034 "3: blt %2,4b\n"
1035 " blbs %0,2b\n"
1036 " br 1b\n"
1037 ".previous"
1038 : "=r" (tmp), "=m" (lock->lock), "=r" (stuck)
1039 : "m" (lock->lock), "2" (stuck) : "memory");
1040
1041 if (stuck < 0) {
1042 printk(KERN_WARNING
1043 "%s:%d spinlock stuck in %s at %p(%d)"
1044 " owner %s at %p(%d) %s:%d\n",
1045 base_file, line_no,
1046 current->comm, inline_pc, cpu,
1047 lock->task->comm, lock->previous,
1048 lock->on_cpu, lock->base_file, lock->line_no);
1049 stuck = 1L << 36;
1050 printed = 1;
1051 goto try_again;
1052 }
1053
1054 /* Exiting. Got the lock. */
1055 lock->on_cpu = cpu;
1056 lock->previous = inline_pc;
1057 lock->task = current;
1058 lock->base_file = base_file;
1059 lock->line_no = line_no;
1060
1061 if (printed) {
1062 printk(KERN_WARNING
1063 "%s:%d spinlock grabbed in %s at %p(%d) %ld ticks\n",
1064 base_file, line_no, current->comm, inline_pc,
1065 cpu, jiffies - started);
1066 }
1067}
1068
1069int
1070debug_spin_trylock(spinlock_t * lock, const char *base_file, int line_no)
1071{
1072 int ret;
1073 if ((ret = !test_and_set_bit(0, lock))) {
1074 lock->on_cpu = smp_processor_id();
1075 lock->previous = __builtin_return_address(0);
1076 lock->task = current;
1077 } else {
1078 lock->base_file = base_file;
1079 lock->line_no = line_no;
1080 }
1081 return ret;
1082}
1083#endif /* CONFIG_DEBUG_SPINLOCK */
1084
1085#ifdef CONFIG_DEBUG_RWLOCK
1086void _raw_write_lock(rwlock_t * lock)
1087{
1088 long regx, regy;
1089 int stuck_lock, stuck_reader;
1090 void *inline_pc = __builtin_return_address(0);
1091
1092 try_again:
1093
1094 stuck_lock = 1<<30;
1095 stuck_reader = 1<<30;
1096
1097 __asm__ __volatile__(
1098 "1: ldl_l %1,%0\n"
1099 " blbs %1,6f\n"
1100 " blt %1,8f\n"
1101 " mov 1,%1\n"
1102 " stl_c %1,%0\n"
1103 " beq %1,6f\n"
1104 "4: mb\n"
1105 ".subsection 2\n"
1106 "6: blt %3,4b # debug\n"
1107 " subl %3,1,%3 # debug\n"
1108 " ldl %1,%0\n"
1109 " blbs %1,6b\n"
1110 "8: blt %4,4b # debug\n"
1111 " subl %4,1,%4 # debug\n"
1112 " ldl %1,%0\n"
1113 " blt %1,8b\n"
1114 " br 1b\n"
1115 ".previous"
1116 : "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (regy),
1117 "=&r" (stuck_lock), "=&r" (stuck_reader)
1118 : "m" (*(volatile int *)lock), "3" (stuck_lock), "4" (stuck_reader) : "memory");
1119
1120 if (stuck_lock < 0) {
1121 printk(KERN_WARNING "write_lock stuck at %p\n", inline_pc);
1122 goto try_again;
1123 }
1124 if (stuck_reader < 0) {
1125 printk(KERN_WARNING "write_lock stuck on readers at %p\n",
1126 inline_pc);
1127 goto try_again;
1128 }
1129}
1130
1131void _raw_read_lock(rwlock_t * lock)
1132{
1133 long regx;
1134 int stuck_lock;
1135 void *inline_pc = __builtin_return_address(0);
1136
1137 try_again:
1138
1139 stuck_lock = 1<<30;
1140
1141 __asm__ __volatile__(
1142 "1: ldl_l %1,%0;"
1143 " blbs %1,6f;"
1144 " subl %1,2,%1;"
1145 " stl_c %1,%0;"
1146 " beq %1,6f;"
1147 "4: mb\n"
1148 ".subsection 2\n"
1149 "6: ldl %1,%0;"
1150 " blt %2,4b # debug\n"
1151 " subl %2,1,%2 # debug\n"
1152 " blbs %1,6b;"
1153 " br 1b\n"
1154 ".previous"
1155 : "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (stuck_lock)
1156 : "m" (*(volatile int *)lock), "2" (stuck_lock) : "memory");
1157
1158 if (stuck_lock < 0) {
1159 printk(KERN_WARNING "read_lock stuck at %p\n", inline_pc);
1160 goto try_again;
1161 }
1162}
1163#endif /* CONFIG_DEBUG_RWLOCK */