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authorIngo Molnar <mingo@elte.hu>2005-09-10 00:25:56 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-10 10:06:21 -0700
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 fc5ef90c4fc..24ae9a36607 100644
--- a/arch/alpha/kernel/alpha_ksyms.c
+++ b/arch/alpha/kernel/alpha_ksyms.c
@@ -185,15 +185,6 @@ EXPORT_SYMBOL(smp_num_cpus);
EXPORT_SYMBOL(smp_call_function);
EXPORT_SYMBOL(smp_call_function_on_cpu);
EXPORT_SYMBOL(_atomic_dec_and_lock);
-#ifdef CONFIG_DEBUG_SPINLOCK
-EXPORT_SYMBOL(_raw_spin_unlock);
-EXPORT_SYMBOL(debug_spin_lock);
-EXPORT_SYMBOL(debug_spin_trylock);
-#endif
-#ifdef CONFIG_DEBUG_RWLOCK
-EXPORT_SYMBOL(_raw_write_lock);
-EXPORT_SYMBOL(_raw_read_lock);
-#endif
EXPORT_SYMBOL(cpu_present_mask);
#endif /* CONFIG_SMP */
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index e211aa7404e..da0be346579 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,
preempt_enable();
}
-
-#ifdef CONFIG_DEBUG_SPINLOCK
-void
-_raw_spin_unlock(spinlock_t * lock)
-{
- mb();
- lock->lock = 0;
-
- lock->on_cpu = -1;
- lock->previous = NULL;
- lock->task = NULL;
- lock->base_file = "none";
- lock->line_no = 0;
-}
-
-void
-debug_spin_lock(spinlock_t * lock, const char *base_file, int line_no)
-{
- long tmp;
- long stuck;
- void *inline_pc = __builtin_return_address(0);
- unsigned long started = jiffies;
- int printed = 0;
- int cpu = smp_processor_id();
-
- stuck = 1L << 30;
- try_again:
-
- /* Use sub-sections to put the actual loop at the end
- of this object file's text section so as to perfect
- branch prediction. */
- __asm__ __volatile__(
- "1: ldl_l %0,%1\n"
- " subq %2,1,%2\n"
- " blbs %0,2f\n"
- " or %0,1,%0\n"
- " stl_c %0,%1\n"
- " beq %0,3f\n"
- "4: mb\n"
- ".subsection 2\n"
- "2: ldl %0,%1\n"
- " subq %2,1,%2\n"
- "3: blt %2,4b\n"
- " blbs %0,2b\n"
- " br 1b\n"
- ".previous"
- : "=r" (tmp), "=m" (lock->lock), "=r" (stuck)
- : "m" (lock->lock), "2" (stuck) : "memory");
-
- if (stuck < 0) {
- printk(KERN_WARNING
- "%s:%d spinlock stuck in %s at %p(%d)"
- " owner %s at %p(%d) %s:%d\n",
- base_file, line_no,
- current->comm, inline_pc, cpu,
- lock->task->comm, lock->previous,
- lock->on_cpu, lock->base_file, lock->line_no);
- stuck = 1L << 36;
- printed = 1;
- goto try_again;
- }
-
- /* Exiting. Got the lock. */
- lock->on_cpu = cpu;
- lock->previous = inline_pc;
- lock->task = current;
- lock->base_file = base_file;
- lock->line_no = line_no;
-
- if (printed) {
- printk(KERN_WARNING
- "%s:%d spinlock grabbed in %s at %p(%d) %ld ticks\n",
- base_file, line_no, current->comm, inline_pc,
- cpu, jiffies - started);
- }
-}
-
-int
-debug_spin_trylock(spinlock_t * lock, const char *base_file, int line_no)
-{
- int ret;
- if ((ret = !test_and_set_bit(0, lock))) {
- lock->on_cpu = smp_processor_id();
- lock->previous = __builtin_return_address(0);
- lock->task = current;
- } else {
- lock->base_file = base_file;
- lock->line_no = line_no;
- }
- return ret;
-}
-#endif /* CONFIG_DEBUG_SPINLOCK */
-
-#ifdef CONFIG_DEBUG_RWLOCK
-void _raw_write_lock(rwlock_t * lock)
-{
- long regx, regy;
- int stuck_lock, stuck_reader;
- void *inline_pc = __builtin_return_address(0);
-
- try_again:
-
- stuck_lock = 1<<30;
- stuck_reader = 1<<30;
-
- __asm__ __volatile__(
- "1: ldl_l %1,%0\n"
- " blbs %1,6f\n"
- " blt %1,8f\n"
- " mov 1,%1\n"
- " stl_c %1,%0\n"
- " beq %1,6f\n"
- "4: mb\n"
- ".subsection 2\n"
- "6: blt %3,4b # debug\n"
- " subl %3,1,%3 # debug\n"
- " ldl %1,%0\n"
- " blbs %1,6b\n"
- "8: blt %4,4b # debug\n"
- " subl %4,1,%4 # debug\n"
- " ldl %1,%0\n"
- " blt %1,8b\n"
- " br 1b\n"
- ".previous"
- : "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (regy),
- "=&r" (stuck_lock), "=&r" (stuck_reader)
- : "m" (*(volatile int *)lock), "3" (stuck_lock), "4" (stuck_reader) : "memory");
-
- if (stuck_lock < 0) {
- printk(KERN_WARNING "write_lock stuck at %p\n", inline_pc);
- goto try_again;
- }
- if (stuck_reader < 0) {
- printk(KERN_WARNING "write_lock stuck on readers at %p\n",
- inline_pc);
- goto try_again;
- }
-}
-
-void _raw_read_lock(rwlock_t * lock)
-{
- long regx;
- int stuck_lock;
- void *inline_pc = __builtin_return_address(0);
-
- try_again:
-
- stuck_lock = 1<<30;
-
- __asm__ __volatile__(
- "1: ldl_l %1,%0;"
- " blbs %1,6f;"
- " subl %1,2,%1;"
- " stl_c %1,%0;"
- " beq %1,6f;"
- "4: mb\n"
- ".subsection 2\n"
- "6: ldl %1,%0;"
- " blt %2,4b # debug\n"
- " subl %2,1,%2 # debug\n"
- " blbs %1,6b;"
- " br 1b\n"
- ".previous"
- : "=m" (*(volatile int *)lock), "=&r" (regx), "=&r" (stuck_lock)
- : "m" (*(volatile int *)lock), "2" (stuck_lock) : "memory");
-
- if (stuck_lock < 0) {
- printk(KERN_WARNING "read_lock stuck at %p\n", inline_pc);
- goto try_again;
- }
-}
-#endif /* CONFIG_DEBUG_RWLOCK */