[RFC/PATCH] Use mmu_gather for /proc stuff instead of flush_tlb_mm()

Benjamin Herrenschmidt
2007-07-09T06:46:54Z

Use mmu_gather for fs/proc/task_mmu.c

This removes the use of flush_tlb_mm() from that proc file, using
an mmu_gather instead.

No signed-off yet, not to be merged at this point.

Index: linux-work/fs/proc/task_mmu.c
===================================================================
--- linux-work.orig/fs/proc/task_mmu.c 2007-07-09 16:27:09.000000000 +1000
+++ linux-work/fs/proc/task_mmu.c 2007-07-09 16:27:47.000000000 +1000
@@ -9,7 +9,7 @@

#include <asm/elf.h>
#include <asm/uaccess.h>
-#include <asm/tlbflush.h>
+#include <asm/tlb.h>
#include "internal.h"

char *task_mem(struct mm_struct *mm, char *buffer)
@@ -124,11 +124,13 @@ struct mem_size_stats
unsigned long referenced;
};

+typedef void (*pmd_action_t)(struct mmu_gather *tlb, struct vm_area_struct *,
+ pmd_t *, unsigned long, unsigned long, void *);
struct pmd_walker {
+ struct mmu_gather *tlb;
struct vm_area_struct *vma;
void *private;
- void (*action)(struct vm_area_struct *, pmd_t *, unsigned long,
- unsigned long, void *);
+ pmd_action_t action;
};

static int show_map_internal(struct seq_file *m, void *v, struct mem_size_stats *mss)
@@ -218,7 +220,8 @@ static int show_map(struct seq_file *m,
return show_map_internal(m, v, NULL);
}

-static void smaps_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
+static void smaps_pte_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
void *private)
{
@@ -258,7 +261,8 @@ static void smaps_pte_range(struct vm_ar
cond_resched();
}

-static void clear_refs_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
+static void clear_refs_pte_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
void *private)
{
@@ -279,6 +283,8 @@ static void clear_refs_pte_range(struct
/* Clear accessed and referenced bits. */
ptep_test_and_clear_young(vma, addr, pte);
ClearPageReferenced(page);
+ if (tlb)
+ tlb_remove_tlb_entry(tlb, pte, addr);
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
@@ -295,7 +301,8 @@ static inline void walk_pmd_range(struct
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
- walker->action(walker->vma, pmd, addr, next, walker->private);
+ walker->action(walker->tlb, walker->vma, pmd, addr, next,
+ walker->private);
}
}

@@ -323,11 +330,9 @@ static inline void walk_pud_range(struct
* Recursively walk the page table for the memory area in a VMA, calling
* a callback for every bottom-level (PTE) page table.
*/
-static inline void walk_page_range(struct vm_area_struct *vma,
- void (*action)(struct vm_area_struct *,
- pmd_t *, unsigned long,
- unsigned long, void *),
- void *private)
+static inline void walk_page_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma,
+ pmd_action_t action, void *private)
{
unsigned long addr = vma->vm_start;
unsigned long end = vma->vm_end;
@@ -335,6 +340,7 @@ static inline void walk_page_range(struc
.vma = vma,
.private = private,
.action = action,
+ .tlb = tlb,
};
pgd_t *pgd;
unsigned long next;
@@ -355,19 +361,25 @@ static int show_smap(struct seq_file *m,

memset(&mss, 0, sizeof mss);
if (vma->vm_mm && !is_vm_hugetlb_page(vma))
- walk_page_range(vma, smaps_pte_range, &mss);
+ walk_page_range(NULL, vma, smaps_pte_range, &mss);
return show_map_internal(m, v, &mss);
}

void clear_refs_smap(struct mm_struct *mm)
{
struct vm_area_struct *vma;
+ struct mmu_gather *tlb;
+ unsigned long end_addr = 0;

down_read(&mm->mmap_sem);
+ tlb = tlb_gather_mmu(mm, 0);
for (vma = mm->mmap; vma; vma = vma->vm_next)
- if (vma->vm_mm && !is_vm_hugetlb_page(vma))
- walk_page_range(vma, clear_refs_pte_range, NULL);
- flush_tlb_mm(mm);
+ if (vma->vm_mm && !is_vm_hugetlb_page(vma)) {
+ end_addr = max(vma->vm_end, end_addr);
+ walk_page_range(tlb, vma, clear_refs_pte_range, NULL);
+ }
+ if (tlb)
+ tlb_finish_mmu(tlb, 0, end_addr);
up_read(&mm->mmap_sem);
}