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mm/rmap: make rmap_walk to get the rmap_walk_control argument
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In each rmap traverse case, there is some difference so that we need
function pointers and arguments to them in order to handle these

For this purpose, struct rmap_walk_control is introduced in this patch,
and will be extended in following patch.  Introducing and extending are
separate, because it clarify changes.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Joonsoo Kim authored and Linus Torvalds committed Jan 22, 2014
1 parent faecd8d commit 051ac83
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Showing 5 changed files with 27 additions and 21 deletions.
7 changes: 3 additions & 4 deletions include/linux/ksm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,8 +76,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
int page_referenced_ksm(struct page *page,
struct mem_cgroup *memcg, unsigned long *vm_flags);
int try_to_unmap_ksm(struct page *page, enum ttu_flags flags);
int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg);
int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
void ksm_migrate_page(struct page *newpage, struct page *oldpage);

#else /* !CONFIG_KSM */
Expand Down Expand Up @@ -120,8 +119,8 @@ static inline int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
return 0;
}

static inline int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page*,
struct vm_area_struct *, unsigned long, void *), void *arg)
static inline int rmap_walk_ksm(struct page *page,
struct rmap_walk_control *rwc)
{
return 0;
}
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9 changes: 7 additions & 2 deletions include/linux/rmap.h
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Original file line number Diff line number Diff line change
Expand Up @@ -235,11 +235,16 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page);
void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);

struct rmap_walk_control {
void *arg;
int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
unsigned long addr, void *arg);
};

/*
* Called by migrate.c to remove migration ptes, but might be used more later.
*/
int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg);
int rmap_walk(struct page *page, struct rmap_walk_control *rwc);

#else /* !CONFIG_MMU */

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6 changes: 3 additions & 3 deletions mm/ksm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1997,8 +1997,7 @@ int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
}

#ifdef CONFIG_MIGRATION
int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg)
int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
{
struct stable_node *stable_node;
struct rmap_item *rmap_item;
Expand Down Expand Up @@ -2033,7 +2032,8 @@ int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
if ((rmap_item->mm == vma->vm_mm) == search_new_forks)
continue;

ret = rmap_one(page, vma, rmap_item->address, arg);
ret = rwc->rmap_one(page, vma,
rmap_item->address, rwc->arg);
if (ret != SWAP_AGAIN) {
anon_vma_unlock_read(anon_vma);
goto out;
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7 changes: 6 additions & 1 deletion mm/migrate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -199,7 +199,12 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
*/
static void remove_migration_ptes(struct page *old, struct page *new)
{
rmap_walk(new, remove_migration_pte, old);
struct rmap_walk_control rwc = {
.rmap_one = remove_migration_pte,
.arg = old,
};

rmap_walk(new, &rwc);
}

/*
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19 changes: 8 additions & 11 deletions mm/rmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1706,8 +1706,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page)
* rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file():
* Called by migrate.c to remove migration ptes, but might be used more later.
*/
static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg)
static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
{
struct anon_vma *anon_vma;
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
Expand All @@ -1721,16 +1720,15 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
ret = rmap_one(page, vma, address, arg);
ret = rwc->rmap_one(page, vma, address, rwc->arg);
if (ret != SWAP_AGAIN)
break;
}
anon_vma_unlock_read(anon_vma);
return ret;
}

static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg)
static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
{
struct address_space *mapping = page->mapping;
pgoff_t pgoff = page->index << compound_order(page);
Expand All @@ -1742,7 +1740,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
mutex_lock(&mapping->i_mmap_mutex);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
ret = rmap_one(page, vma, address, arg);
ret = rwc->rmap_one(page, vma, address, rwc->arg);
if (ret != SWAP_AGAIN)
break;
}
Expand All @@ -1755,17 +1753,16 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
return ret;
}

int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg)
int rmap_walk(struct page *page, struct rmap_walk_control *rwc)
{
VM_BUG_ON(!PageLocked(page));

if (unlikely(PageKsm(page)))
return rmap_walk_ksm(page, rmap_one, arg);
return rmap_walk_ksm(page, rwc);
else if (PageAnon(page))
return rmap_walk_anon(page, rmap_one, arg);
return rmap_walk_anon(page, rwc);
else
return rmap_walk_file(page, rmap_one, arg);
return rmap_walk_file(page, rwc);
}
#endif /* CONFIG_MIGRATION */

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