[PATCH v2 10/20] mm: Introduce __lru_cache_add_active_or_unevictable

From: Laurent Dufour
Date: Thu Aug 17 2017 - 18:11:35 EST


The speculative page fault handler which is run without holding the
mmap_sem is calling lru_cache_add_active_or_unevictable() but the vm_flags
is not guaranteed to remain constant.
Introducing __lru_cache_add_active_or_unevictable() which has the vma flags
value parameter instead of the vma pointer.

Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
---
include/linux/swap.h | 11 +++++++++--
mm/memory.c | 8 ++++----
mm/swap.c | 12 ++++++------
3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index d83d28e53e62..fdea932fe10f 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -285,8 +285,15 @@ extern void swap_setup(void);

extern void add_page_to_unevictable_list(struct page *page);

-extern void lru_cache_add_active_or_unevictable(struct page *page,
- struct vm_area_struct *vma);
+extern void __lru_cache_add_active_or_unevictable(struct page *page,
+ unsigned long vma_flags);
+
+static inline void lru_cache_add_active_or_unevictable(struct page *page,
+ struct vm_area_struct *vma)
+{
+ return __lru_cache_add_active_or_unevictable(page, vma->vm_flags);
+}
+

/* linux/mm/vmscan.c */
extern unsigned long zone_reclaimable_pages(struct zone *zone);
diff --git a/mm/memory.c b/mm/memory.c
index 53528eeee2b3..c6b18cc87e90 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2370,7 +2370,7 @@ static int wp_page_copy(struct vm_fault *vmf)
ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
page_add_new_anon_rmap(new_page, vma, vmf->address, false);
mem_cgroup_commit_charge(new_page, memcg, false, false);
- lru_cache_add_active_or_unevictable(new_page, vma);
+ __lru_cache_add_active_or_unevictable(new_page, vmf->vma_flags);
/*
* We call the notify macro here because, when using secondary
* mmu page tables (such as kvm shadow page tables), we want the
@@ -2840,7 +2840,7 @@ int do_swap_page(struct vm_fault *vmf)
} else { /* ksm created a completely new copy */
page_add_new_anon_rmap(page, vma, vmf->address, false);
mem_cgroup_commit_charge(page, memcg, false, false);
- lru_cache_add_active_or_unevictable(page, vma);
+ __lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
}

swap_free(entry);
@@ -2978,7 +2978,7 @@ static int do_anonymous_page(struct vm_fault *vmf)
inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
page_add_new_anon_rmap(page, vma, vmf->address, false);
mem_cgroup_commit_charge(page, memcg, false, false);
- lru_cache_add_active_or_unevictable(page, vma);
+ __lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
setpte:
set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);

@@ -3230,7 +3230,7 @@ int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
page_add_new_anon_rmap(page, vma, vmf->address, false);
mem_cgroup_commit_charge(page, memcg, false, false);
- lru_cache_add_active_or_unevictable(page, vma);
+ __lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
} else {
inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
page_add_file_rmap(page, false);
diff --git a/mm/swap.c b/mm/swap.c
index 60b1d2a75852..ece0826a205b 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -470,21 +470,21 @@ void add_page_to_unevictable_list(struct page *page)
}

/**
- * lru_cache_add_active_or_unevictable
- * @page: the page to be added to LRU
- * @vma: vma in which page is mapped for determining reclaimability
+ * __lru_cache_add_active_or_unevictable
+ * @page: the page to be added to LRU
+ * @vma_flags: vma in which page is mapped for determining reclaimability
*
* Place @page on the active or unevictable LRU list, depending on its
* evictability. Note that if the page is not evictable, it goes
* directly back onto it's zone's unevictable list, it does NOT use a
* per cpu pagevec.
*/
-void lru_cache_add_active_or_unevictable(struct page *page,
- struct vm_area_struct *vma)
+void __lru_cache_add_active_or_unevictable(struct page *page,
+ unsigned long vma_flags)
{
VM_BUG_ON_PAGE(PageLRU(page), page);

- if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) {
+ if (likely((vma_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) {
SetPageActive(page);
lru_cache_add(page);
return;
--
2.7.4