Just forward mail.
-------- Forwarded Message --------
Subject: [PATCH] mm: memcontrol: Let mem_cgroup_move_account() have effect only
if MMU enabled
Date: Tue, 03 Mar 2015 06:42:01 +0800
From: Chen Gang <762976...@qq.com>
To: han...@cmpxchg.org, mho...@suse.cz
CC: cgro...@vger.kernel.org, linux...@kvack.org, linux-kernel@vger.kernel.org
<linux-kernel@vger.kernel.org>
When !MMU, it will report warning. The related warning with allmodconfig
under c6x:
CC mm/memcontrol.o
mm/memcontrol.c:2802:12: warning: 'mem_cgroup_move_account' defined but not
used [-Wunused-function]
static int mem_cgroup_move_account(struct page *page,
^
Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
---
mm/memcontrol.c | 172 ++++++++++++++++++++++++++++----------------------------
1 file changed, 86 insertions(+), 86 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0c86945..80f26f5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2785,92 +2785,6 @@ void mem_cgroup_split_huge_fixup(struct page *head)
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-/**
- * mem_cgroup_move_account - move account of the page
- * @page: the page
- * @nr_pages: number of regular pages (>1 for huge pages)
- * @from: mem_cgroup which the page is moved from.
- * @to: mem_cgroup which the page is moved to. @from != @to.
- *
- * The caller must confirm following.
- * - page is not on LRU (isolate_page() is useful.)
- * - compound_lock is held when nr_pages > 1
- *
- * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
- * from old cgroup.
- */
-static int mem_cgroup_move_account(struct page *page,
- unsigned int nr_pages,
- struct mem_cgroup *from,
- struct mem_cgroup *to)
-{
- unsigned long flags;
- int ret;
-
- VM_BUG_ON(from == to);
- VM_BUG_ON_PAGE(PageLRU(page), page);
- /*
- * The page is isolated from LRU. So, collapse function
- * will not handle this page. But page splitting can happen.
- * Do this check under compound_page_lock(). The caller should
- * hold it.
- */
- ret = -EBUSY;
- if (nr_pages > 1 && !PageTransHuge(page))
- goto out;
-
- /*
- * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup
- * of its source page while we change it: page migration takes
- * both pages off the LRU, but page cache replacement doesn't.
- */
- if (!trylock_page(page))
- goto out;
-
- ret = -EINVAL;
- if (page->mem_cgroup != from)
- goto out_unlock;
-
- spin_lock_irqsave(&from->move_lock, flags);
-
- if (!PageAnon(page) && page_mapped(page)) {
- __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
- nr_pages);
- __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
- nr_pages);
- }
-
- if (PageWriteback(page)) {
- __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
- nr_pages);
- __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
- nr_pages);
- }
-
- /*
- * It is safe to change page->mem_cgroup here because the page
- * is referenced, charged, and isolated - we can't race with
- * uncharging, charging, migration, or LRU putback.
- */
-
- /* caller should have done css_get */
- page->mem_cgroup = to;
- spin_unlock_irqrestore(&from->move_lock, flags);
-
- ret = 0;
-
- local_irq_disable();
- mem_cgroup_charge_statistics(to, page, nr_pages);
- memcg_check_events(to, page);
- mem_cgroup_charge_statistics(from, page, -nr_pages);
- memcg_check_events(from, page);
- local_irq_enable();
-out_unlock:
- unlock_page(page);
-out:
- return ret;
-}
-
#ifdef CONFIG_MEMCG_SWAP
static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
bool charge)
@@ -4822,6 +4736,92 @@ static struct page *mc_handle_file_pte(struct
vm_area_struct *vma,
return page;
}
+/**
+ * mem_cgroup_move_account - move account of the page
+ * @page: the page
+ * @nr_pages: number of regular pages (>1 for huge pages)
+ * @from: mem_cgroup which the page is moved from.
+ * @to: mem_cgroup which the page is moved to. @from != @to.
+ *
+ * The caller must confirm following.
+ * - page is not on LRU (isolate_page() is useful.)
+ * - compound_lock is held when nr_pages > 1
+ *
+ * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
+ * from old cgroup.
+ */
+static int mem_cgroup_move_account(struct page *page,
+ unsigned int nr_pages,
+ struct mem_cgroup *from,
+ struct mem_cgroup *to)
+{
+ unsigned long flags;
+ int ret;
+
+ VM_BUG_ON(from == to);
+ VM_BUG_ON_PAGE(PageLRU(page), page);
+ /*
+ * The page is isolated from LRU. So, collapse function
+ * will not handle this page. But page splitting can happen.
+ * Do this check under compound_page_lock(). The caller should
+ * hold it.
+ */
+ ret = -EBUSY;
+ if (nr_pages > 1 && !PageTransHuge(page))
+ goto out;
+
+ /*
+ * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup
+ * of its source page while we change it: page migration takes
+ * both pages off the LRU, but page cache replacement doesn't.
+ */
+ if (!trylock_page(page))
+ goto out;
+
+ ret = -EINVAL;
+ if (page->mem_cgroup != from)
+ goto out_unlock;
+
+ spin_lock_irqsave(&from->move_lock, flags);
+
+ if (!PageAnon(page) && page_mapped(page)) {
+ __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
+ nr_pages);
+ __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
+ nr_pages);
+ }
+
+ if (PageWriteback(page)) {
+ __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
+ nr_pages);
+ __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
+ nr_pages);
+ }
+
+ /*
+ * It is safe to change page->mem_cgroup here because the page
+ * is referenced, charged, and isolated - we can't race with
+ * uncharging, charging, migration, or LRU putback.
+ */
+
+ /* caller should have done css_get */
+ page->mem_cgroup = to;
+ spin_unlock_irqrestore(&from->move_lock, flags);
+
+ ret = 0;
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(to, page, nr_pages);
+ memcg_check_events(to, page);
+ mem_cgroup_charge_statistics(from, page, -nr_pages);
+ memcg_check_events(from, page);
+ local_irq_enable();
+out_unlock:
+ unlock_page(page);
+out:
+ return ret;
+}
+
static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent, union mc_target *target)
{
--
1.9.3
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