From: David S. Miller Date: Thu, 23 Feb 2006 22:19:28 +0000 (-0800) Subject: [SPARC64]: Fix TLB context allocation with SMT style shared TLBs. X-Git-Tag: v2.6.17-rc1~1184^2~42 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a0663a79ad4faebe1db4a56e2e767b120b12333a;p=linux-2.6 [SPARC64]: Fix TLB context allocation with SMT style shared TLBs. The context allocation scheme we use depends upon there being a 1<-->1 mapping from cpu to physical TLB for correctness. Chips like Niagara break this assumption. So what we do is notify all cpus with a cross call when the context version number changes, and if necessary this makes them allocate a valid context for the address space they are running at the time. Stress tested with make -j1024, make -j2048, and make -j4096 kernel builds on a 32-strand, 8 core, T2000 with 16GB of ram. Signed-off-by: David S. Miller --- diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c index 0cd9b16612..1ce9408114 100644 --- a/arch/sparc64/kernel/smp.c +++ b/arch/sparc64/kernel/smp.c @@ -885,26 +885,44 @@ void flush_dcache_page_all(struct mm_struct *mm, struct page *page) put_cpu(); } +static void __smp_receive_signal_mask(cpumask_t mask) +{ + smp_cross_call_masked(&xcall_receive_signal, 0, 0, 0, mask); +} + void smp_receive_signal(int cpu) { cpumask_t mask = cpumask_of_cpu(cpu); - if (cpu_online(cpu)) { - u64 data0 = (((u64)&xcall_receive_signal) & 0xffffffff); - - if (tlb_type == spitfire) - spitfire_xcall_deliver(data0, 0, 0, mask); - else if (tlb_type == cheetah || tlb_type == cheetah_plus) - cheetah_xcall_deliver(data0, 0, 0, mask); - else if (tlb_type == hypervisor) - hypervisor_xcall_deliver(data0, 0, 0, mask); - } + if (cpu_online(cpu)) + __smp_receive_signal_mask(mask); } void smp_receive_signal_client(int irq, struct pt_regs *regs) { - /* Just return, rtrap takes care of the rest. */ + struct mm_struct *mm; + clear_softint(1 << irq); + + /* See if we need to allocate a new TLB context because + * the version of the one we are using is now out of date. + */ + mm = current->active_mm; + if (likely(mm)) { + if (unlikely(!CTX_VALID(mm->context))) { + unsigned long flags; + + spin_lock_irqsave(&mm->context.lock, flags); + get_new_mmu_context(mm); + load_secondary_context(mm); + spin_unlock_irqrestore(&mm->context.lock, flags); + } + } +} + +void smp_new_mmu_context_version(void) +{ + __smp_receive_signal_mask(cpu_online_map); } void smp_report_regs(void) diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c index 16f0db38d9..ccf083aecb 100644 --- a/arch/sparc64/mm/init.c +++ b/arch/sparc64/mm/init.c @@ -629,17 +629,20 @@ void __flush_dcache_range(unsigned long start, unsigned long end) * let the user have CTX 0 (nucleus) or we ever use a CTX * version of zero (and thus NO_CONTEXT would not be caught * by version mis-match tests in mmu_context.h). + * + * Always invoked with interrupts disabled. */ void get_new_mmu_context(struct mm_struct *mm) { unsigned long ctx, new_ctx; unsigned long orig_pgsz_bits; - + int new_version; spin_lock(&ctx_alloc_lock); orig_pgsz_bits = (mm->context.sparc64_ctx_val & CTX_PGSZ_MASK); ctx = (tlb_context_cache + 1) & CTX_NR_MASK; new_ctx = find_next_zero_bit(mmu_context_bmap, 1 << CTX_NR_BITS, ctx); + new_version = 0; if (new_ctx >= (1 << CTX_NR_BITS)) { new_ctx = find_next_zero_bit(mmu_context_bmap, ctx, 1); if (new_ctx >= ctx) { @@ -662,6 +665,7 @@ void get_new_mmu_context(struct mm_struct *mm) mmu_context_bmap[i + 2] = 0; mmu_context_bmap[i + 3] = 0; } + new_version = 1; goto out; } } @@ -671,6 +675,9 @@ out: tlb_context_cache = new_ctx; mm->context.sparc64_ctx_val = new_ctx | orig_pgsz_bits; spin_unlock(&ctx_alloc_lock); + + if (unlikely(new_version)) + smp_new_mmu_context_version(); } void sparc_ultra_dump_itlb(void) diff --git a/include/asm-sparc64/mmu.h b/include/asm-sparc64/mmu.h index 473d990848..1504d303a1 100644 --- a/include/asm-sparc64/mmu.h +++ b/include/asm-sparc64/mmu.h @@ -102,6 +102,7 @@ extern void __tsb_insert(unsigned long ent, unsigned long tag, unsigned long pte extern void tsb_flush(unsigned long ent, unsigned long tag); typedef struct { + spinlock_t lock; unsigned long sparc64_ctx_val; struct tsb *tsb; unsigned long tsb_rss_limit; diff --git a/include/asm-sparc64/mmu_context.h b/include/asm-sparc64/mmu_context.h index eb660b1609..4be40c58e3 100644 --- a/include/asm-sparc64/mmu_context.h +++ b/include/asm-sparc64/mmu_context.h @@ -19,6 +19,12 @@ extern unsigned long tlb_context_cache; extern unsigned long mmu_context_bmap[]; extern void get_new_mmu_context(struct mm_struct *mm); +#ifdef CONFIG_SMP +extern void smp_new_mmu_context_version(void); +#else +#define smp_new_mmu_context_version() do { } while (0) +#endif + extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm); extern void destroy_context(struct mm_struct *mm); @@ -58,21 +64,17 @@ extern void smp_tsb_sync(struct mm_struct *mm); extern void __flush_tlb_mm(unsigned long, unsigned long); -/* Switch the current MM context. */ +/* Switch the current MM context. Interrupts are disabled. */ static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk) { unsigned long ctx_valid; int cpu; - /* Note: page_table_lock is used here to serialize switch_mm - * and activate_mm, and their calls to get_new_mmu_context. - * This use of page_table_lock is unrelated to its other uses. - */ - spin_lock(&mm->page_table_lock); + spin_lock(&mm->context.lock); ctx_valid = CTX_VALID(mm->context); if (!ctx_valid) get_new_mmu_context(mm); - spin_unlock(&mm->page_table_lock); + spin_unlock(&mm->context.lock); if (!ctx_valid || (old_mm != mm)) { load_secondary_context(mm); @@ -98,19 +100,16 @@ static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, str /* Activate a new MM instance for the current task. */ static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm) { + unsigned long flags; int cpu; - /* Note: page_table_lock is used here to serialize switch_mm - * and activate_mm, and their calls to get_new_mmu_context. - * This use of page_table_lock is unrelated to its other uses. - */ - spin_lock(&mm->page_table_lock); + spin_lock_irqsave(&mm->context.lock, flags); if (!CTX_VALID(mm->context)) get_new_mmu_context(mm); cpu = smp_processor_id(); if (!cpu_isset(cpu, mm->cpu_vm_mask)) cpu_set(cpu, mm->cpu_vm_mask); - spin_unlock(&mm->page_table_lock); + spin_unlock_irqrestore(&mm->context.lock, flags); load_secondary_context(mm); __flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT);