Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266275AbUFYOYs (ORCPT ); Fri, 25 Jun 2004 10:24:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266743AbUFYOYs (ORCPT ); Fri, 25 Jun 2004 10:24:48 -0400 Received: from cfcafw.sgi.com ([198.149.23.1]:58067 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S266275AbUFYOX5 (ORCPT ); Fri, 25 Jun 2004 10:23:57 -0400 Date: Fri, 25 Jun 2004 09:23:16 -0500 From: Jack Steiner To: Andrew Morton Cc: davidm@hpl.hp.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] - Reduce TLB flushing during process migration Message-ID: <20040625142315.GA22598@sgi.com> References: <20040623143844.GA15670@sgi.com> <20040623143318.07932255.akpm@osdl.org> <20040624125544.GA15742@sgi.com> <20040624114449.47fe2f67.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040624114449.47fe2f67.akpm@osdl.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8895 Lines: 248 On Thu, Jun 24, 2004 at 11:44:49AM -0700, Andrew Morton wrote: > > And it's calling it with a null pointer for kernel threads, which oopses on > i386. We went over this weeks ago. Whoops. I missed that. On IA64, it is safe to call flush_tlb_mm() with a NULL pointer. > > Shouldn't asm-generic.h be doing > > #define tlb_migrate_finish(mm) do {} while (0) > > ? > You are right. I made the change that you suggested. Here is the updated patch (includes the update to cachetlb.txt). Signed-off-by: Jack Steiner diff -uprN linuxbase/arch/ia64/kernel/machvec.c linux/arch/ia64/kernel/machvec.c --- linuxbase/arch/ia64/kernel/machvec.c 2004-05-21 20:47:20.000000000 -0500 +++ linux/arch/ia64/kernel/machvec.c 2004-06-22 15:04:06.000000000 -0500 @@ -62,6 +62,12 @@ machvec_timer_interrupt (int irq, void * EXPORT_SYMBOL(machvec_timer_interrupt); void +machvec_tlb_migrate_finish (struct mm_struct *mm) +{ +} +EXPORT_SYMBOL(machvec_tlb_migrate_finish); + +void machvec_dma_sync_single (struct device *hwdev, dma_addr_t dma_handle, size_t size, int dir) { mb(); diff -uprN linuxbase/arch/ia64/sn/kernel/sn2/sn2_smp.c linux/arch/ia64/sn/kernel/sn2/sn2_smp.c --- linuxbase/arch/ia64/sn/kernel/sn2/sn2_smp.c 2004-05-21 20:47:20.000000000 -0500 +++ linux/arch/ia64/sn/kernel/sn2/sn2_smp.c 2004-06-22 15:04:06.000000000 -0500 @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -60,6 +61,13 @@ wait_piowc(void) } +void +sn_tlb_migrate_finish(struct mm_struct *mm) +{ + if (mm == current->mm) + flush_tlb_mm(mm); +} + /** * sn2_global_tlb_purge - globally purge translation cache of virtual address range @@ -114,6 +122,13 @@ sn2_global_tlb_purge (unsigned long star return; } + if (atomic_read(&mm->mm_users) == 1) { + flush_tlb_mm(mm); + preempt_enable(); + return; + } + + nix = 0; for (cnode=find_first_bit(&nodes_flushed, NR_NODES); cnode < NR_NODES; cnode=find_next_bit(&nodes_flushed, NR_NODES, ++cnode)) diff -uprN linuxbase/Documentation/cachetlb.txt linux/Documentation/cachetlb.txt --- linuxbase/Documentation/cachetlb.txt 2004-06-22 07:15:46.000000000 -0500 +++ linux/Documentation/cachetlb.txt 2004-06-24 07:54:50.000000000 -0500 @@ -132,6 +132,17 @@ changes occur: translations for software managed TLB configurations. The sparc64 port currently does this. +7) void tlb_migrate_finish(struct mm_struct *mm) + + This interface is called at the end of an explicit + process migration. This interface provides a hook + to allow a platform to update TLB or context-specific + information for the address space. + + The ia64 sn2 platform is one example of a platform + that uses this interface. + + Next, we have the cache flushing interfaces. In general, when Linux is changing an existing virtual-->physical mapping to a new value, the sequence will be in one of the following forms: diff -uprN linuxbase/include/asm-generic/tlb.h linux/include/asm-generic/tlb.h --- linuxbase/include/asm-generic/tlb.h 2004-06-22 07:15:51.000000000 -0500 +++ linux/include/asm-generic/tlb.h 2004-06-25 09:00:01.000000000 -0500 @@ -147,4 +147,6 @@ static inline void tlb_remove_page(struc __pmd_free_tlb(tlb, pmdp); \ } while (0) +#define tlb_migrate_finish(mm) do {} while (0) + #endif /* _ASM_GENERIC__TLB_H */ diff -uprN linuxbase/include/asm-ia64/machvec.h linux/include/asm-ia64/machvec.h --- linuxbase/include/asm-ia64/machvec.h 2004-05-21 20:47:29.000000000 -0500 +++ linux/include/asm-ia64/machvec.h 2004-06-22 15:04:06.000000000 -0500 @@ -19,6 +19,7 @@ struct pt_regs; struct scatterlist; struct irq_desc; struct page; +struct mm_struct; typedef void ia64_mv_setup_t (char **); typedef void ia64_mv_cpu_init_t (void); @@ -26,6 +27,7 @@ typedef void ia64_mv_irq_init_t (void); typedef void ia64_mv_send_ipi_t (int, int, int, int); typedef void ia64_mv_timer_interrupt_t (int, void *, struct pt_regs *); typedef void ia64_mv_global_tlb_purge_t (unsigned long, unsigned long, unsigned long); +typedef void ia64_mv_tlb_migrate_finish_t (struct mm_struct *); typedef struct irq_desc *ia64_mv_irq_desc (unsigned int); typedef u8 ia64_mv_irq_to_vector (u8); typedef unsigned int ia64_mv_local_vector_to_irq (u8 vector); @@ -72,6 +74,7 @@ typedef unsigned long ia64_mv_readq_rela extern void machvec_noop (void); extern void machvec_setup (char **); extern void machvec_timer_interrupt (int, void *, struct pt_regs *); +extern void machvec_tlb_migrate_finish (struct mm_struct *); extern void machvec_dma_sync_single (struct device *, dma_addr_t, size_t, int); extern void machvec_dma_sync_sg (struct device *, struct scatterlist *, int, int); @@ -95,6 +98,7 @@ extern void machvec_dma_sync_sg (struct # define platform_send_ipi ia64_mv.send_ipi # define platform_timer_interrupt ia64_mv.timer_interrupt # define platform_global_tlb_purge ia64_mv.global_tlb_purge +# define platform_tlb_migrate_finish ia64_mv.tlb_migrate_finish # define platform_dma_init ia64_mv.dma_init # define platform_dma_alloc_coherent ia64_mv.dma_alloc_coherent # define platform_dma_free_coherent ia64_mv.dma_free_coherent @@ -140,6 +144,7 @@ struct ia64_machine_vector { ia64_mv_send_ipi_t *send_ipi; ia64_mv_timer_interrupt_t *timer_interrupt; ia64_mv_global_tlb_purge_t *global_tlb_purge; + ia64_mv_tlb_migrate_finish_t *tlb_migrate_finish; ia64_mv_dma_init *dma_init; ia64_mv_dma_alloc_coherent *dma_alloc_coherent; ia64_mv_dma_free_coherent *dma_free_coherent; @@ -181,6 +186,7 @@ struct ia64_machine_vector { platform_send_ipi, \ platform_timer_interrupt, \ platform_global_tlb_purge, \ + platform_tlb_migrate_finish, \ platform_dma_init, \ platform_dma_alloc_coherent, \ platform_dma_free_coherent, \ @@ -260,6 +266,9 @@ extern ia64_mv_dma_supported swiotlb_dm #ifndef platform_global_tlb_purge # define platform_global_tlb_purge ia64_global_tlb_purge /* default to architected version */ #endif +#ifndef platform_tlb_migrate_finish +# define platform_tlb_migrate_finish machvec_tlb_migrate_finish +#endif #ifndef platform_dma_init # define platform_dma_init swiotlb_init #endif diff -uprN linuxbase/include/asm-ia64/machvec_sn2.h linux/include/asm-ia64/machvec_sn2.h --- linuxbase/include/asm-ia64/machvec_sn2.h 2004-05-21 20:47:29.000000000 -0500 +++ linux/include/asm-ia64/machvec_sn2.h 2004-06-22 15:04:06.000000000 -0500 @@ -39,6 +39,7 @@ extern ia64_mv_irq_init_t sn_irq_init; extern ia64_mv_send_ipi_t sn2_send_IPI; extern ia64_mv_timer_interrupt_t sn_timer_interrupt; extern ia64_mv_global_tlb_purge_t sn2_global_tlb_purge; +extern ia64_mv_tlb_migrate_finish_t sn_tlb_migrate_finish; extern ia64_mv_irq_desc sn_irq_desc; extern ia64_mv_irq_to_vector sn_irq_to_vector; extern ia64_mv_local_vector_to_irq sn_local_vector_to_irq; @@ -83,6 +84,7 @@ extern ia64_mv_dma_supported sn_dma_sup #define platform_send_ipi sn2_send_IPI #define platform_timer_interrupt sn_timer_interrupt #define platform_global_tlb_purge sn2_global_tlb_purge +#define platform_tlb_migrate_finish sn_tlb_migrate_finish #define platform_pci_fixup sn_pci_fixup #define platform_inb __sn_inb #define platform_inw __sn_inw diff -uprN linuxbase/include/asm-ia64/tlb.h linux/include/asm-ia64/tlb.h --- linuxbase/include/asm-ia64/tlb.h 2004-05-21 20:47:29.000000000 -0500 +++ linux/include/asm-ia64/tlb.h 2004-06-22 15:04:06.000000000 -0500 @@ -44,6 +44,7 @@ #include #include #include +#include #ifdef CONFIG_SMP # define FREE_PTE_NR 2048 @@ -211,6 +212,8 @@ __tlb_remove_tlb_entry (struct mmu_gathe tlb->end_addr = address + PAGE_SIZE; } +#define tlb_migrate_finish(mm) platform_tlb_migrate_finish(mm) + #define tlb_start_vma(tlb, vma) do { } while (0) #define tlb_end_vma(tlb, vma) do { } while (0) diff -uprN linuxbase/kernel/sched.c linux/kernel/sched.c --- linuxbase/kernel/sched.c 2004-06-22 07:15:51.000000000 -0500 +++ linux/kernel/sched.c 2004-06-22 15:05:15.000000000 -0500 @@ -40,6 +40,7 @@ #include #include #include +#include #include @@ -3335,6 +3336,7 @@ int set_cpus_allowed(task_t *p, cpumask_ task_rq_unlock(rq, &flags); wake_up_process(rq->migration_thread); wait_for_completion(&req.done); + tlb_migrate_finish(p->mm); return 0; } out: -- Thanks Jack Steiner (steiner@sgi.com) 651-683-5302 Principal Engineer SGI - Silicon Graphics, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/