Subject: + mm-rmap-use-rmap_walk-in-try_to_munlock.patch added to -mm tree
To: iamjoonsoo.kim@xxxxxxx,dhillf@xxxxxxxxx,hughd@xxxxxxxxxx,mgorman@xxxxxxx,mingo@xxxxxxxxxx,n-horiguchi@xxxxxxxxxxxxx,riel@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 04 Dec 2013 14:16:48 -0800
The patch titled
Subject: mm/rmap: use rmap_walk() in try_to_munlock()
has been added to the -mm tree. Its filename is
mm-rmap-use-rmap_walk-in-try_to_munlock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-rmap-use-rmap_walk-in-try_to_munlock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-rmap-use-rmap_walk-in-try_to_munlock.patch
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From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm/rmap: use rmap_walk() in try_to_munlock()
Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.
So, just use it in try_to_munlock().
In this patch, I change following things.
1. remove some variants of rmap traversing functions.
cf> try_to_unmap_ksm, try_to_unmap_anon, try_to_unmap_file
2. mechanical change to use rmap_walk() in try_to_munlock().
3. copy and paste comments.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Hillf Danton <dhillf@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/ksm.h | 6 -
mm/ksm.c | 50 -------------
mm/rmap.c | 154 +++++++++++-------------------------------
3 files changed, 42 insertions(+), 168 deletions(-)
diff -puN include/linux/ksm.h~mm-rmap-use-rmap_walk-in-try_to_munlock include/linux/ksm.h
--- a/include/linux/ksm.h~mm-rmap-use-rmap_walk-in-try_to_munlock
+++ a/include/linux/ksm.h
@@ -75,7 +75,6 @@ struct page *ksm_might_need_to_copy(stru
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, struct rmap_walk_control *rwc);
void ksm_migrate_page(struct page *newpage, struct page *oldpage);
@@ -113,11 +112,6 @@ static inline int page_referenced_ksm(st
{
return 0;
}
-
-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,
struct rmap_walk_control *rwc)
diff -puN mm/ksm.c~mm-rmap-use-rmap_walk-in-try_to_munlock mm/ksm.c
--- a/mm/ksm.c~mm-rmap-use-rmap_walk-in-try_to_munlock
+++ a/mm/ksm.c
@@ -1946,56 +1946,6 @@ out:
return referenced;
}
-int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
-{
- struct stable_node *stable_node;
- struct rmap_item *rmap_item;
- int ret = SWAP_AGAIN;
- int search_new_forks = 0;
-
- VM_BUG_ON(!PageKsm(page));
- VM_BUG_ON(!PageLocked(page));
-
- stable_node = page_stable_node(page);
- if (!stable_node)
- return SWAP_FAIL;
-again:
- hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
- struct anon_vma *anon_vma = rmap_item->anon_vma;
- struct anon_vma_chain *vmac;
- struct vm_area_struct *vma;
-
- anon_vma_lock_read(anon_vma);
- anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
- 0, ULONG_MAX) {
- vma = vmac->vma;
- if (rmap_item->address < vma->vm_start ||
- rmap_item->address >= vma->vm_end)
- continue;
- /*
- * Initially we examine only the vma which covers this
- * rmap_item; but later, if there is still work to do,
- * we examine covering vmas in other mms: in case they
- * were forked from the original since ksmd passed.
- */
- if ((rmap_item->mm == vma->vm_mm) == search_new_forks)
- continue;
-
- ret = try_to_unmap_one(page, vma,
- rmap_item->address, (void *)flags);
- if (ret != SWAP_AGAIN || !page_mapped(page)) {
- anon_vma_unlock_read(anon_vma);
- goto out;
- }
- }
- anon_vma_unlock_read(anon_vma);
- }
- if (!search_new_forks++)
- goto again;
-out:
- return ret;
-}
-
int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
{
struct stable_node *stable_node;
diff -puN mm/rmap.c~mm-rmap-use-rmap_walk-in-try_to_munlock mm/rmap.c
--- a/mm/rmap.c~mm-rmap-use-rmap_walk-in-try_to_munlock
+++ a/mm/rmap.c
@@ -1173,9 +1173,6 @@ out:
}
/*
- * Subfunctions of try_to_unmap: try_to_unmap_one called
- * repeatedly from try_to_unmap_ksm, try_to_unmap_anon or try_to_unmap_file.
- *
* @arg: enum ttu_flags will be passed to this argument
*/
int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
@@ -1517,107 +1514,6 @@ static bool invalid_migration_vma(struct
return is_vma_temporary_stack(vma);
}
-/**
- * try_to_unmap_anon - unmap or unlock anonymous page using the object-based
- * rmap method
- * @page: the page to unmap/unlock
- * @flags: action and flags
- *
- * Find all the mappings of a page using the mapping pointer and the vma chains
- * contained in the anon_vma struct it points to.
- *
- * This function is only called from try_to_unmap/try_to_munlock for
- * anonymous pages.
- * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
- * where the page was found will be held for write. So, we won't recheck
- * vm_flags for that VMA. That should be OK, because that vma shouldn't be
- * 'LOCKED.
- */
-static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
-{
- struct anon_vma *anon_vma;
- pgoff_t pgoff;
- struct anon_vma_chain *avc;
- int ret = SWAP_AGAIN;
-
- anon_vma = page_lock_anon_vma_read(page);
- if (!anon_vma)
- return ret;
-
- pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
- struct vm_area_struct *vma = avc->vma;
- unsigned long address;
-
- /*
- * During exec, a temporary VMA is setup and later moved.
- * The VMA is moved under the anon_vma lock but not the
- * page tables leading to a race where migration cannot
- * find the migration ptes. Rather than increasing the
- * locking requirements of exec(), migration skips
- * temporary VMAs until after exec() completes.
- */
- if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) &&
- is_vma_temporary_stack(vma))
- continue;
-
- address = vma_address(page, vma);
- ret = try_to_unmap_one(page, vma, address, (void *)flags);
- if (ret != SWAP_AGAIN || !page_mapped(page))
- break;
- }
-
- page_unlock_anon_vma_read(anon_vma);
- return ret;
-}
-
-/**
- * try_to_unmap_file - unmap/unlock file page using the object-based rmap method
- * @page: the page to unmap/unlock
- * @flags: action and flags
- *
- * Find all the mappings of a page using the mapping pointer and the vma chains
- * contained in the address_space struct it points to.
- *
- * This function is only called from try_to_unmap/try_to_munlock for
- * object-based pages.
- * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
- * where the page was found will be held for write. So, we won't recheck
- * vm_flags for that VMA. That should be OK, because that vma shouldn't be
- * 'LOCKED.
- */
-static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
-{
- struct address_space *mapping = page->mapping;
- pgoff_t pgoff = page->index << compound_order(page);
- struct vm_area_struct *vma;
- int ret = SWAP_AGAIN;
-
- mutex_lock(&mapping->i_mmap_mutex);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
- unsigned long address = vma_address(page, vma);
- ret = try_to_unmap_one(page, vma, address, (void *)flags);
- if (ret != SWAP_AGAIN || !page_mapped(page))
- goto out;
- }
-
- if (list_empty(&mapping->i_mmap_nonlinear))
- goto out;
-
- /*
- * We don't bother to try to find the munlocked page in nonlinears.
- * It's costly. Instead, later, page reclaim logic may call
- * try_to_unmap(TTU_MUNLOCK) and recover PG_mlocked lazily.
- */
- if (TTU_ACTION(flags) == TTU_MUNLOCK)
- goto out;
-
- ret = try_to_unmap_nonlinear(page, mapping, vma);
-out:
- mutex_unlock(&mapping->i_mmap_mutex);
- return ret;
-}
-
static int page_not_mapped(struct page *page)
{
return !page_mapped(page);
@@ -1685,14 +1581,25 @@ int try_to_unmap(struct page *page, enum
*/
int try_to_munlock(struct page *page)
{
+ int ret;
+ struct rmap_walk_control rwc = {
+ .rmap_one = try_to_unmap_one,
+ .arg = (void *)TTU_MUNLOCK,
+ .done = page_not_mapped,
+ /*
+ * We don't bother to try to find the munlocked page in
+ * nonlinears. It's costly. Instead, later, page reclaim logic
+ * may call try_to_unmap() and recover PG_mlocked lazily.
+ */
+ .file_nonlinear = NULL,
+ .anon_lock = page_lock_anon_vma_read,
+
+ };
+
VM_BUG_ON(!PageLocked(page) || PageLRU(page));
- if (unlikely(PageKsm(page)))
- return try_to_unmap_ksm(page, TTU_MUNLOCK);
- else if (PageAnon(page))
- return try_to_unmap_anon(page, TTU_MUNLOCK);
- else
- return try_to_unmap_file(page, TTU_MUNLOCK);
+ ret = rmap_walk(page, &rwc);
+ return ret;
}
void __put_anon_vma(struct anon_vma *anon_vma)
@@ -1728,8 +1635,18 @@ static struct anon_vma *rmap_walk_anon_l
}
/*
- * 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.
+ * rmap_walk_anon - do something to anonymous page using the object-based
+ * rmap method
+ * @page: the page to be handled
+ * @rwc: control variable according to each walk type
+ *
+ * Find all the mappings of a page using the mapping pointer and the vma chains
+ * contained in the anon_vma struct it points to.
+ *
+ * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
+ * where the page was found will be held for write. So, we won't recheck
+ * vm_flags for that VMA. That should be OK, because that vma shouldn't be
+ * LOCKED.
*/
static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
{
@@ -1759,6 +1676,19 @@ static int rmap_walk_anon(struct page *p
return ret;
}
+/*
+ * rmap_walk_file - do something to file page using the object-based rmap method
+ * @page: the page to be handled
+ * @rwc: control variable according to each walk type
+ *
+ * Find all the mappings of a page using the mapping pointer and the vma chains
+ * contained in the address_space struct it points to.
+ *
+ * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
+ * where the page was found will be held for write. So, we won't recheck
+ * vm_flags for that VMA. That should be OK, because that vma shouldn't be
+ * LOCKED.
+ */
static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
{
struct address_space *mapping = page->mapping;
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
mm-rmap-recompute-pgoff-for-huge-page.patch
mm-rmap-factor-nonlinear-handling-out-of-try_to_unmap_file.patch
mm-rmap-factor-lock-function-out-of-rmap_walk_anon.patch
mm-rmap-make-rmap_walk-to-get-the-rmap_walk_control-argument.patch
mm-rmap-extend-rmap_walk_xxx-to-cope-with-different-cases.patch
mm-rmap-use-rmap_walk-in-try_to_unmap.patch
mm-rmap-use-rmap_walk-in-try_to_munlock.patch
mm-rmap-use-rmap_walk-in-page_referenced.patch
mm-rmap-use-rmap_walk-in-page_mkclean.patch
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