#include <linux/memcontrol.h>
#include <linux/gfp.h>
#include <linux/uio.h>
-#include <linux/hugetlb.h>
#include "internal.h"
spin_lock_irqsave(&zone->lru_lock, flags);
lruvec = mem_cgroup_page_lruvec(page, zone);
- VM_BUG_ON(!PageLRU(page));
+ VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
spin_unlock_irqrestore(&zone->lru_lock, flags);
static void put_compound_page(struct page *page)
{
- if (unlikely(PageTail(page))) {
- /* __split_huge_page_refcount can run under us */
- struct page *page_head = compound_trans_head(page);
-
- if (likely(page != page_head &&
- get_page_unless_zero(page_head))) {
- unsigned long flags;
+ struct page *page_head;
+ if (likely(!PageTail(page))) {
+ if (put_page_testzero(page)) {
/*
- * THP can not break up slab pages so avoid taking
- * compound_lock(). Slab performs non-atomic bit ops
- * on page->flags for better performance. In particular
- * slab_unlock() in slub used to be a hot path. It is
- * still hot on arches that do not support
- * this_cpu_cmpxchg_double().
+ * By the time all refcounts have been released
+ * split_huge_page cannot run anymore from under us.
*/
- if (PageSlab(page_head) || PageHeadHuge(page_head)) {
- if (likely(PageTail(page))) {
- /*
- * __split_huge_page_refcount
- * cannot race here.
- */
- VM_BUG_ON(!PageHead(page_head));
- atomic_dec(&page->_mapcount);
- if (put_page_testzero(page_head))
- VM_BUG_ON(1);
- if (put_page_testzero(page_head))
- __put_compound_page(page_head);
- return;
- } else
- /*
- * __split_huge_page_refcount
- * run before us, "page" was a
- * THP tail. The split
- * page_head has been freed
- * and reallocated as slab or
- * hugetlbfs page of smaller
- * order (only possible if
- * reallocated as slab on
- * x86).
- */
- goto skip_lock;
- }
+ if (PageHead(page))
+ __put_compound_page(page);
+ else
+ __put_single_page(page);
+ }
+ return;
+ }
+
+ /* __split_huge_page_refcount can run under us */
+ page_head = compound_head(page);
+
+ /*
+ * THP can not break up slab pages so avoid taking
+ * compound_lock() and skip the tail page refcounting (in
+ * _mapcount) too. Slab performs non-atomic bit ops on
+ * page->flags for better performance. In particular
+ * slab_unlock() in slub used to be a hot path. It is still
+ * hot on arches that do not support
+ * this_cpu_cmpxchg_double().
+ *
+ * If "page" is part of a slab or hugetlbfs page it cannot be
+ * splitted and the head page cannot change from under us. And
+ * if "page" is part of a THP page under splitting, if the
+ * head page pointed by the THP tail isn't a THP head anymore,
+ * we'll find PageTail clear after smp_rmb() and we'll treat
+ * it as a single page.
+ */
+ if (!__compound_tail_refcounted(page_head)) {
+ /*
+ * If "page" is a THP tail, we must read the tail page
+ * flags after the head page flags. The
+ * split_huge_page side enforces write memory barriers
+ * between clearing PageTail and before the head page
+ * can be freed and reallocated.
+ */
+ smp_rmb();
+ if (likely(PageTail(page))) {
/*
- * page_head wasn't a dangling pointer but it
- * may not be a head page anymore by the time
- * we obtain the lock. That is ok as long as it
- * can't be freed from under us.
+ * __split_huge_page_refcount cannot race
+ * here.
*/
- flags = compound_lock_irqsave(page_head);
- if (unlikely(!PageTail(page))) {
- /* __split_huge_page_refcount run before us */
- compound_unlock_irqrestore(page_head, flags);
-skip_lock:
- if (put_page_testzero(page_head)) {
- /*
- * The head page may have been
- * freed and reallocated as a
- * compound page of smaller
- * order and then freed again.
- * All we know is that it
- * cannot have become: a THP
- * page, a compound page of
- * higher order, a tail page.
- * That is because we still
- * hold the refcount of the
- * split THP tail and
- * page_head was the THP head
- * before the split.
- */
- if (PageHead(page_head))
- __put_compound_page(page_head);
- else
- __put_single_page(page_head);
- }
-out_put_single:
- if (put_page_testzero(page))
- __put_single_page(page);
- return;
+ VM_BUG_ON_PAGE(!PageHead(page_head), page_head);
+ VM_BUG_ON_PAGE(page_mapcount(page) != 0, page);
+ if (put_page_testzero(page_head)) {
+ /*
+ * If this is the tail of a slab
+ * compound page, the tail pin must
+ * not be the last reference held on
+ * the page, because the PG_slab
+ * cannot be cleared before all tail
+ * pins (which skips the _mapcount
+ * tail refcounting) have been
+ * released. For hugetlbfs the tail
+ * pin may be the last reference on
+ * the page instead, because
+ * PageHeadHuge will not go away until
+ * the compound page enters the buddy
+ * allocator.
+ */
+ VM_BUG_ON_PAGE(PageSlab(page_head), page_head);
+ __put_compound_page(page_head);
}
- VM_BUG_ON(page_head != page->first_page);
+ return;
+ } else
/*
- * We can release the refcount taken by
- * get_page_unless_zero() now that
- * __split_huge_page_refcount() is blocked on
- * the compound_lock.
+ * __split_huge_page_refcount run before us,
+ * "page" was a THP tail. The split page_head
+ * has been freed and reallocated as slab or
+ * hugetlbfs page of smaller order (only
+ * possible if reallocated as slab on x86).
*/
- if (put_page_testzero(page_head))
- VM_BUG_ON(1);
- /* __split_huge_page_refcount will wait now */
- VM_BUG_ON(page_mapcount(page) <= 0);
- atomic_dec(&page->_mapcount);
- VM_BUG_ON(atomic_read(&page_head->_count) <= 0);
- VM_BUG_ON(atomic_read(&page->_count) != 0);
- compound_unlock_irqrestore(page_head, flags);
+ goto out_put_single;
+ }
+ if (likely(page != page_head && get_page_unless_zero(page_head))) {
+ unsigned long flags;
+
+ /*
+ * page_head wasn't a dangling pointer but it may not
+ * be a head page anymore by the time we obtain the
+ * lock. That is ok as long as it can't be freed from
+ * under us.
+ */
+ flags = compound_lock_irqsave(page_head);
+ if (unlikely(!PageTail(page))) {
+ /* __split_huge_page_refcount run before us */
+ compound_unlock_irqrestore(page_head, flags);
if (put_page_testzero(page_head)) {
+ /*
+ * The head page may have been freed
+ * and reallocated as a compound page
+ * of smaller order and then freed
+ * again. All we know is that it
+ * cannot have become: a THP page, a
+ * compound page of higher order, a
+ * tail page. That is because we
+ * still hold the refcount of the
+ * split THP tail and page_head was
+ * the THP head before the split.
+ */
if (PageHead(page_head))
__put_compound_page(page_head);
else
__put_single_page(page_head);
}
- } else {
- /* page_head is a dangling pointer */
- VM_BUG_ON(PageTail(page));
- goto out_put_single;
+out_put_single:
+ if (put_page_testzero(page))
+ __put_single_page(page);
+ return;
}
- } else if (put_page_testzero(page)) {
- if (PageHead(page))
- __put_compound_page(page);
- else
- __put_single_page(page);
+ VM_BUG_ON_PAGE(page_head != page->first_page, page);
+ /*
+ * We can release the refcount taken by
+ * get_page_unless_zero() now that
+ * __split_huge_page_refcount() is blocked on the
+ * compound_lock.
+ */
+ if (put_page_testzero(page_head))
+ VM_BUG_ON_PAGE(1, page_head);
+ /* __split_huge_page_refcount will wait now */
+ VM_BUG_ON_PAGE(page_mapcount(page) <= 0, page);
+ atomic_dec(&page->_mapcount);
+ VM_BUG_ON_PAGE(atomic_read(&page_head->_count) <= 0, page_head);
+ VM_BUG_ON_PAGE(atomic_read(&page->_count) != 0, page);
+ compound_unlock_irqrestore(page_head, flags);
+
+ if (put_page_testzero(page_head)) {
+ if (PageHead(page_head))
+ __put_compound_page(page_head);
+ else
+ __put_single_page(page_head);
+ }
+ } else {
+ /* page_head is a dangling pointer */
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ goto out_put_single;
}
}
* split_huge_page().
*/
unsigned long flags;
- bool got = false;
- struct page *page_head = compound_trans_head(page);
+ bool got;
+ struct page *page_head = compound_head(page);
- if (likely(page != page_head && get_page_unless_zero(page_head))) {
- /* Ref to put_compound_page() comment. */
- if (PageSlab(page_head) || PageHeadHuge(page_head)) {
- if (likely(PageTail(page))) {
- /*
- * This is a hugetlbfs page or a slab
- * page. __split_huge_page_refcount
- * cannot race here.
- */
- VM_BUG_ON(!PageHead(page_head));
- __get_page_tail_foll(page, false);
- return true;
- } else {
- /*
- * __split_huge_page_refcount run
- * before us, "page" was a THP
- * tail. The split page_head has been
- * freed and reallocated as slab or
- * hugetlbfs page of smaller order
- * (only possible if reallocated as
- * slab on x86).
- */
- put_page(page_head);
- return false;
- }
+ /* Ref to put_compound_page() comment. */
+ if (!__compound_tail_refcounted(page_head)) {
+ smp_rmb();
+ if (likely(PageTail(page))) {
+ /*
+ * This is a hugetlbfs page or a slab
+ * page. __split_huge_page_refcount
+ * cannot race here.
+ */
+ VM_BUG_ON_PAGE(!PageHead(page_head), page_head);
+ __get_page_tail_foll(page, true);
+ return true;
+ } else {
+ /*
+ * __split_huge_page_refcount run
+ * before us, "page" was a THP
+ * tail. The split page_head has been
+ * freed and reallocated as slab or
+ * hugetlbfs page of smaller order
+ * (only possible if reallocated as
+ * slab on x86).
+ */
+ return false;
}
+ }
+ got = false;
+ if (likely(page != page_head && get_page_unless_zero(page_head))) {
/*
* page_head wasn't a dangling pointer but it
* may not be a head page anymore by the time
*/
void lru_cache_add(struct page *page)
{
- VM_BUG_ON(PageActive(page) && PageUnevictable(page));
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
+ VM_BUG_ON_PAGE(PageLRU(page), page);
__lru_cache_add(page);
}
}
lruvec = mem_cgroup_page_lruvec(page, zone);
- VM_BUG_ON(!PageLRU(page));
+ VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
}
{
const int file = 0;
- VM_BUG_ON(!PageHead(page));
- VM_BUG_ON(PageCompound(page_tail));
- VM_BUG_ON(PageLRU(page_tail));
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ VM_BUG_ON_PAGE(PageCompound(page_tail), page);
+ VM_BUG_ON_PAGE(PageLRU(page_tail), page);
VM_BUG_ON(NR_CPUS != 1 &&
!spin_is_locked(&lruvec_zone(lruvec)->lru_lock));
int active = PageActive(page);
enum lru_list lru = page_lru(page);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, lru);
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blobdiff