[RFC/PATCH 4/12] disconnect sparc64 tlb flush from mmu_gather

From: Benjamin Herrenschmidt
Date: Tue Aug 07 2007 - 03:21:31 EST

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sparc64 current tlb flush needs it's per-cpu list of vaddr's. This
patch disconnect that from the mmu_gather, allowing sparc64 to use
the generic implementation of the later for now.

This is somewhat temporary. It allows to keep sparc64 working while
I'm doing surgery on mmu_gather. Once the later goes fully stack
based and provide a non-percpu way of storing the page list along
with arch specific informations, I'll be able to reconnect sparc64
to it (and get rid of the get_cpu/put_cpu and associated preempt
disabling).

Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
---

arch/sparc64/kernel/smp.c | 2
arch/sparc64/mm/tlb.c | 43 ++++++++++--------
arch/sparc64/mm/tsb.c | 6 +-
arch/sparc64/mm/ultra.S | 12 ++---
include/asm-sparc64/system.h | 2
include/asm-sparc64/tlb.h | 95 +++++++++--------------------------------
include/asm-sparc64/tlbflush.h | 4 -
7 files changed, 59 insertions(+), 105 deletions(-)

Index: linux-work/arch/sparc64/mm/tlb.c
===================================================================
--- linux-work.orig/arch/sparc64/mm/tlb.c 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/arch/sparc64/mm/tlb.c 2007-07-27 18:06:44.000000000 +1000
@@ -19,35 +19,38 @@

/* Heavily inspired by the ppc64 code. */

-DEFINE_PER_CPU(struct mmu_gather, mmu_gathers) = { 0, };
+DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
+DEFINE_PER_CPU(struct tlb_batch, tlb_batch);

-void flush_tlb_pending(void)
+void __flush_tlb_pending(struct tlb_batch *mp)
{
- struct mmu_gather *mp = &__get_cpu_var(mmu_gathers);
-
- preempt_disable();
-
- if (mp->tlb_nr) {
+ if (mp->nr) {
flush_tsb_user(mp);

if (CTX_VALID(mp->mm->context)) {
#ifdef CONFIG_SMP
- smp_flush_tlb_pending(mp->mm, mp->tlb_nr,
+ smp_flush_tlb_pending(mp->mm, mp->nr,
&mp->vaddrs[0]);
#else
- __flush_tlb_pending(CTX_HWBITS(mp->mm->context),
- mp->tlb_nr, &mp->vaddrs[0]);
+ local_flush_tlb_pending(CTX_HWBITS(mp->mm->context),
+ mp->nr, &mp->vaddrs[0]);
#endif
}
- mp->tlb_nr = 0;
+ mp->nr = 0;
}
+}
+
+void flush_tlb_pending(void)
+{
+ struct tlb_batch *mp = &get_cpu_var(tlb_batch);

- preempt_enable();
+ __flush_tlb_pending(mp);
+ put_cpu_var(tlb_batch);
}

void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, pte_t *ptep, pte_t orig)
{
- struct mmu_gather *mp = &__get_cpu_var(mmu_gathers);
+ struct tlb_batch *mp;
unsigned long nr;

vaddr &= PAGE_MASK;
@@ -79,13 +82,17 @@ void tlb_batch_add(struct mm_struct *mm,

no_cache_flush:

- if (mp->fullmm)
+ if (test_bit(MMF_DEAD, &mm->flags))
return;

- nr = mp->tlb_nr;
+ /* we are called with enough spinlocks held to make
+ * preempt disable useless here
+ */
+ mp = &__get_cpu_var(tlb_batch);
+ nr = mp->nr;

if (unlikely(nr != 0 && mm != mp->mm)) {
- flush_tlb_pending();
+ __flush_tlb_pending(mp);
nr = 0;
}

@@ -93,7 +100,7 @@ no_cache_flush:
mp->mm = mm;

mp->vaddrs[nr] = vaddr;
- mp->tlb_nr = ++nr;
+ mp->nr = ++nr;
if (nr >= TLB_BATCH_NR)
- flush_tlb_pending();
+ __flush_tlb_pending(mp);
}
Index: linux-work/arch/sparc64/mm/tsb.c
===================================================================
--- linux-work.orig/arch/sparc64/mm/tsb.c 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/arch/sparc64/mm/tsb.c 2007-07-27 18:06:44.000000000 +1000
@@ -47,11 +47,11 @@ void flush_tsb_kernel_range(unsigned lon
}
}

-static void __flush_tsb_one(struct mmu_gather *mp, unsigned long hash_shift, unsigned long tsb, unsigned long nentries)
+static void __flush_tsb_one(struct tlb_batch *mp, unsigned long hash_shift, unsigned long tsb, unsigned long nentries)
{
unsigned long i;

- for (i = 0; i < mp->tlb_nr; i++) {
+ for (i = 0; i < mp->nr; i++) {
unsigned long v = mp->vaddrs[i];
unsigned long tag, ent, hash;

@@ -65,7 +65,7 @@ static void __flush_tsb_one(struct mmu_g
}
}

-void flush_tsb_user(struct mmu_gather *mp)
+void flush_tsb_user(struct tlb_batch *mp)
{
struct mm_struct *mm = mp->mm;
unsigned long nentries, base, flags;
Index: linux-work/arch/sparc64/mm/ultra.S
===================================================================
--- linux-work.orig/arch/sparc64/mm/ultra.S 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/arch/sparc64/mm/ultra.S 2007-07-27 18:06:44.000000000 +1000
@@ -52,8 +52,8 @@ __flush_tlb_mm: /* 18 insns */
nop

.align 32
- .globl __flush_tlb_pending
-__flush_tlb_pending: /* 26 insns */
+ .globl local_flush_tlb_pending
+local_flush_tlb_pending: /* 26 insns */
/* %o0 = context, %o1 = nr, %o2 = vaddrs[] */
rdpr %pstate, %g7
sllx %o1, 3, %o1
@@ -346,8 +346,8 @@ cheetah_patch_cachetlbops:
call tlb_patch_one
mov 19, %o2

- sethi %hi(__flush_tlb_pending), %o0
- or %o0, %lo(__flush_tlb_pending), %o0
+ sethi %hi(local_flush_tlb_pending), %o0
+ or %o0, %lo(local_flush_tlb_pending), %o0
sethi %hi(__cheetah_flush_tlb_pending), %o1
or %o1, %lo(__cheetah_flush_tlb_pending), %o1
call tlb_patch_one
@@ -699,8 +699,8 @@ hypervisor_patch_cachetlbops:
call tlb_patch_one
mov 10, %o2

- sethi %hi(__flush_tlb_pending), %o0
- or %o0, %lo(__flush_tlb_pending), %o0
+ sethi %hi(local_flush_tlb_pending), %o0
+ or %o0, %lo(local_flush_tlb_pending), %o0
sethi %hi(__hypervisor_flush_tlb_pending), %o1
or %o1, %lo(__hypervisor_flush_tlb_pending), %o1
call tlb_patch_one
Index: linux-work/include/asm-sparc64/tlb.h
===================================================================
--- linux-work.orig/include/asm-sparc64/tlb.h 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/include/asm-sparc64/tlb.h 2007-07-27 18:06:44.000000000 +1000
@@ -7,62 +7,38 @@
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>

-#define TLB_BATCH_NR 192
+#define tlb_flush(mp) \
+do { \
+ if (!test_bit(MMF_DEAD, &mp->mm->flags)) \
+ flush_tlb_pending(); \
+} while(0)

-/*
- * For UP we don't need to worry about TLB flush
- * and page free order so much..
- */
-#ifdef CONFIG_SMP
- #define FREE_PTE_NR 506
- #define tlb_fast_mode(bp) ((bp)->pages_nr == ~0U)
-#else
- #define FREE_PTE_NR 1
- #define tlb_fast_mode(bp) 1
-#endif
+#include <asm-generic/tlb.h>
+
+#define TLB_BATCH_NR 192

-struct mmu_gather {
+struct tlb_batch {
struct mm_struct *mm;
- unsigned int pages_nr;
- unsigned int need_flush;
- unsigned int fullmm;
- unsigned int tlb_nr;
unsigned long vaddrs[TLB_BATCH_NR];
- struct page *pages[FREE_PTE_NR];
+ unsigned int nr;
};
-
-DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+DECLARE_PER_CPU(struct tlb_batch, tlb_batch);

#ifdef CONFIG_SMP
extern void smp_flush_tlb_pending(struct mm_struct *,
unsigned long, unsigned long *);
#endif

-extern void __flush_tlb_pending(unsigned long, unsigned long, unsigned long *);
+extern void local_flush_tlb_pending(unsigned long, unsigned long, unsigned long *);
+extern void __flush_tlb_pending(struct tlb_batch *mp);
extern void flush_tlb_pending(void);

-static inline struct mmu_gather *tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
-{
- struct mmu_gather *mp = &get_cpu_var(mmu_gathers);
-
- BUG_ON(mp->tlb_nr);
-
- mp->mm = mm;
- mp->pages_nr = num_online_cpus() > 1 ? 0U : ~0U;
- mp->fullmm = full_mm_flush;
-
- return mp;
-}
-
-
-static inline void tlb_flush_mmu(struct mmu_gather *mp)
+/* for use by _switch() */
+static inline void check_flush_tlb_pending(void)
{
- if (mp->need_flush) {
- free_pages_and_swap_cache(mp->pages, mp->pages_nr);
- mp->pages_nr = 0;
- mp->need_flush = 0;
- }
-
+ struct tlb_batch *mp = &__get_cpu_var(tlb_batch);
+ if (mp->nr)
+ __flush_tlb_pending(mp);
}

#ifdef CONFIG_SMP
@@ -72,39 +48,10 @@ extern void smp_flush_tlb_mm(struct mm_s
#define do_flush_tlb_mm(mm) __flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT)
#endif

-static inline void tlb_finish_mmu(struct mmu_gather *mp, unsigned long start, unsigned long end)
-{
- tlb_flush_mmu(mp);
-
- if (mp->fullmm)
- mp->fullmm = 0;
- else
- flush_tlb_pending();
-
- /* keep the page table cache within bounds */
- check_pgt_cache();
-
- put_cpu_var(mmu_gathers);
-}
-
-static inline void tlb_remove_page(struct mmu_gather *mp, struct page *page)
-{
- if (tlb_fast_mode(mp)) {
- free_page_and_swap_cache(page);
- return;
- }
- mp->need_flush = 1;
- mp->pages[mp->pages_nr++] = page;
- if (mp->pages_nr >= FREE_PTE_NR)
- tlb_flush_mmu(mp);
-}
-
-#define tlb_remove_tlb_entry(mp,ptep,addr) do { } while (0)
-#define pte_free_tlb(mp,ptepage) pte_free(ptepage)
-#define pmd_free_tlb(mp,pmdp) pmd_free(pmdp)
-#define pud_free_tlb(tlb,pudp) __pud_free_tlb(tlb,pudp)
+#define __tlb_remove_tlb_entry(mp,ptep,addr) do { } while (0)
+#define __pte_free_tlb(mp,ptepage) pte_free(ptepage)
+#define __pmd_free_tlb(mp,pmdp) pmd_free(pmdp)

-#define tlb_migrate_finish(mm) do { } while (0)
#define tlb_start_vma(tlb, vma) do { } while (0)
#define tlb_end_vma(tlb, vma) do { } while (0)

Index: linux-work/include/asm-sparc64/tlbflush.h
===================================================================
--- linux-work.orig/include/asm-sparc64/tlbflush.h 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/include/asm-sparc64/tlbflush.h 2007-07-27 18:06:44.000000000 +1000
@@ -5,9 +5,9 @@
#include <asm/mmu_context.h>

/* TSB flush operations. */
-struct mmu_gather;
+struct tlb_batch;
extern void flush_tsb_kernel_range(unsigned long start, unsigned long end);
-extern void flush_tsb_user(struct mmu_gather *mp);
+extern void flush_tsb_user(struct tlb_batch *mp);

/* TLB flush operations. */

Index: linux-work/arch/sparc64/kernel/smp.c
===================================================================
--- linux-work.orig/arch/sparc64/kernel/smp.c 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/arch/sparc64/kernel/smp.c 2007-07-27 18:06:44.000000000 +1000
@@ -1142,7 +1142,7 @@ void smp_flush_tlb_pending(struct mm_str
ctx, nr, (unsigned long) vaddrs,
mm->cpu_vm_mask);

- __flush_tlb_pending(ctx, nr, vaddrs);
+ local_flush_tlb_pending(ctx, nr, vaddrs);

put_cpu();
}
Index: linux-work/include/asm-sparc64/system.h
===================================================================
--- linux-work.orig/include/asm-sparc64/system.h 2007-07-27 18:06:08.000000000 +1000
+++ linux-work/include/asm-sparc64/system.h 2007-07-27 18:06:44.000000000 +1000
@@ -151,7 +151,7 @@ do { if (test_thread_flag(TIF_PERFCTR))
current_thread_info()->kernel_cntd0 += (unsigned int)(__tmp);\
current_thread_info()->kernel_cntd1 += ((__tmp) >> 32); \
} \
- flush_tlb_pending(); \
+ check_flush_tlb_pending(); \
save_and_clear_fpu(); \
/* If you are tempted to conditionalize the following */ \
/* so that ASI is only written if it changes, think again. */ \
-
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Next message: Benjamin Herrenschmidt: "[RFC/PATCH 5/12] Add mm argument to pte/pmd/pud/pgd_free."
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