[PATCH v6 14/18] s390/tlb: convert to generic mmu_gather

From: Peter Zijlstra
Date: Tue Feb 19 2019 - 05:33:37 EST



Cc: heiko.carstens@xxxxxxxxxx
Cc: npiggin@xxxxxxxxx
Cc: akpm@xxxxxxxxxxxxxxxxxxxx
Cc: aneesh.kumar@xxxxxxxxxxxxxxxxxx
Cc: will.deacon@xxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: linux@xxxxxxxxxxxxxxx
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180918125151.31744-3-schwidefsky@xxxxxxxxxx
---
arch/s390/Kconfig | 2
arch/s390/include/asm/tlb.h | 128 +++++++++++++-------------------------------
arch/s390/mm/pgalloc.c | 63 ---------------------
3 files changed, 42 insertions(+), 151 deletions(-)

--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -163,11 +163,13 @@ config S390
select HAVE_PERF_USER_STACK_DUMP
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MEMBLOCK_PHYS_MAP
+ select HAVE_MMU_GATHER_NO_GATHER
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NOP_MCOUNT
select HAVE_OPROFILE
select HAVE_PCI
select HAVE_PERF_EVENTS
+ select HAVE_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -22,98 +22,39 @@
* Pages used for the page tables is a different story. FIXME: more
*/

-#include <linux/mm.h>
-#include <linux/pagemap.h>
-#include <linux/swap.h>
-#include <asm/processor.h>
-#include <asm/pgalloc.h>
-#include <asm/tlbflush.h>
-
-struct mmu_gather {
- struct mm_struct *mm;
- struct mmu_table_batch *batch;
- unsigned int fullmm;
- unsigned long start, end;
-};
-
-struct mmu_table_batch {
- struct rcu_head rcu;
- unsigned int nr;
- void *tables[0];
-};
-
-#define MAX_TABLE_BATCH \
- ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
-
-extern void tlb_table_flush(struct mmu_gather *tlb);
-extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
-
-static inline void
-arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
- unsigned long start, unsigned long end)
-{
- tlb->mm = mm;
- tlb->start = start;
- tlb->end = end;
- tlb->fullmm = !(start | (end+1));
- tlb->batch = NULL;
-}
-
-static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
-{
- __tlb_flush_mm_lazy(tlb->mm);
-}
-
-static inline void tlb_flush_mmu_free(struct mmu_gather *tlb)
-{
- tlb_table_flush(tlb);
-}
-
+void __tlb_remove_table(void *_table);
+static inline void tlb_flush(struct mmu_gather *tlb);
+static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
+ struct page *page, int page_size);

-static inline void tlb_flush_mmu(struct mmu_gather *tlb)
-{
- tlb_flush_mmu_tlbonly(tlb);
- tlb_flush_mmu_free(tlb);
-}
+#define tlb_start_vma(tlb, vma) do { } while (0)
+#define tlb_end_vma(tlb, vma) do { } while (0)

-static inline void
-arch_tlb_finish_mmu(struct mmu_gather *tlb,
- unsigned long start, unsigned long end, bool force)
-{
- if (force) {
- tlb->start = start;
- tlb->end = end;
- }
+#define tlb_flush tlb_flush
+#define pte_free_tlb pte_free_tlb
+#define pmd_free_tlb pmd_free_tlb
+#define p4d_free_tlb p4d_free_tlb
+#define pud_free_tlb pud_free_tlb

- tlb_flush_mmu(tlb);
-}
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm-generic/tlb.h>

/*
* Release the page cache reference for a pte removed by
* tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
* has already been freed, so just do free_page_and_swap_cache.
*/
-static inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- free_page_and_swap_cache(page);
- return false; /* avoid calling tlb_flush_mmu */
-}
-
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- free_page_and_swap_cache(page);
-}
-
static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
struct page *page, int page_size)
{
- return __tlb_remove_page(tlb, page);
+ free_page_and_swap_cache(page);
+ return false;
}

-static inline void tlb_remove_page_size(struct mmu_gather *tlb,
- struct page *page, int page_size)
+static inline void tlb_flush(struct mmu_gather *tlb)
{
- return tlb_remove_page(tlb, page);
+ __tlb_flush_mm_lazy(tlb->mm);
}

/*
@@ -121,8 +62,17 @@ static inline void tlb_remove_page_size(
* page table from the tlb.
*/
static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
- unsigned long address)
+ unsigned long address)
{
+ __tlb_adjust_range(tlb, address, PAGE_SIZE);
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_ptes = 1;
+ /*
+ * page_table_free_rcu takes care of the allocation bit masks
+ * of the 2K table fragments in the 4K page table page,
+ * then calls tlb_remove_table.
+ */
page_table_free_rcu(tlb, (unsigned long *) pte, address);
}

@@ -139,6 +89,10 @@ static inline void pmd_free_tlb(struct m
if (mm_pmd_folded(tlb->mm))
return;
pgtable_pmd_page_dtor(virt_to_page(pmd));
+ __tlb_adjust_range(tlb, address, PAGE_SIZE);
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_puds = 1;
tlb_remove_table(tlb, pmd);
}

@@ -154,6 +108,10 @@ static inline void p4d_free_tlb(struct m
{
if (mm_p4d_folded(tlb->mm))
return;
+ __tlb_adjust_range(tlb, address, PAGE_SIZE);
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_p4ds = 1;
tlb_remove_table(tlb, p4d);
}

@@ -169,19 +127,11 @@ static inline void pud_free_tlb(struct m
{
if (mm_pud_folded(tlb->mm))
return;
+ tlb->mm->context.flush_mm = 1;
+ tlb->freed_tables = 1;
+ tlb->cleared_puds = 1;
tlb_remove_table(tlb, pud);
}

-#define tlb_start_vma(tlb, vma) do { } while (0)
-#define tlb_end_vma(tlb, vma) do { } while (0)
-#define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0)
-#define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0)
-#define tlb_migrate_finish(mm) do { } while (0)
-#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \
- tlb_remove_tlb_entry(tlb, ptep, address)
-
-static inline void tlb_change_page_size(struct mmu_gather *tlb, unsigned int page_size)
-{
-}

#endif /* _S390_TLB_H */
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -290,7 +290,7 @@ void page_table_free_rcu(struct mmu_gath
tlb_remove_table(tlb, table);
}

-static void __tlb_remove_table(void *_table)
+void __tlb_remove_table(void *_table)
{
unsigned int mask = (unsigned long) _table & 3;
void *table = (void *)((unsigned long) _table ^ mask);
@@ -316,67 +316,6 @@ static void __tlb_remove_table(void *_ta
}
}

-static void tlb_remove_table_smp_sync(void *arg)
-{
- /* Simply deliver the interrupt */
-}
-
-static void tlb_remove_table_one(void *table)
-{
- /*
- * This isn't an RCU grace period and hence the page-tables cannot be
- * assumed to be actually RCU-freed.
- *
- * It is however sufficient for software page-table walkers that rely
- * on IRQ disabling. See the comment near struct mmu_table_batch.
- */
- smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
- __tlb_remove_table(table);
-}
-
-static void tlb_remove_table_rcu(struct rcu_head *head)
-{
- struct mmu_table_batch *batch;
- int i;
-
- batch = container_of(head, struct mmu_table_batch, rcu);
-
- for (i = 0; i < batch->nr; i++)
- __tlb_remove_table(batch->tables[i]);
-
- free_page((unsigned long)batch);
-}
-
-void tlb_table_flush(struct mmu_gather *tlb)
-{
- struct mmu_table_batch **batch = &tlb->batch;
-
- if (*batch) {
- call_rcu(&(*batch)->rcu, tlb_remove_table_rcu);
- *batch = NULL;
- }
-}
-
-void tlb_remove_table(struct mmu_gather *tlb, void *table)
-{
- struct mmu_table_batch **batch = &tlb->batch;
-
- tlb->mm->context.flush_mm = 1;
- if (*batch == NULL) {
- *batch = (struct mmu_table_batch *)
- __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
- if (*batch == NULL) {
- __tlb_flush_mm_lazy(tlb->mm);
- tlb_remove_table_one(table);
- return;
- }
- (*batch)->nr = 0;
- }
- (*batch)->tables[(*batch)->nr++] = table;
- if ((*batch)->nr == MAX_TABLE_BATCH)
- tlb_flush_mmu(tlb);
-}
-
/*
* Base infrastructure required to generate basic asces, region, segment,
* and page tables that do not make use of enhanced features like EDAT1.