[PATCH 3/3] thp: introduce khugepaged_cleanup_page

From: Xiao Guangrong
Date: Wed Sep 12 2012 - 08:57:29 EST


It is used to release the page on the fail path, then the page need not
be cleaned up in khugepaged_prealloc_page anymore

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 19 +++++++++++++++----
1 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5622347..de0a028 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1827,9 +1827,6 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
*wait = false;
*hpage = NULL;
khugepaged_alloc_sleep();
- } else if (*hpage) {
- put_page(*hpage);
- *hpage = NULL;
}

return true;
@@ -1863,6 +1860,13 @@ static struct page
count_vm_event(THP_COLLAPSE_ALLOC);
return *hpage;
}
+
+static void khugepaged_cleanup_page(struct page **hpage)
+{
+ VM_BUG_ON(!*hpage);
+ put_page(*hpage);
+ *hpage = NULL;
+}
#else
static struct page *khugepaged_alloc_hugepage(bool *wait)
{
@@ -1903,6 +1907,10 @@ static struct page
VM_BUG_ON(!*hpage);
return *hpage;
}
+
+static void khugepaged_cleanup_page(struct page **hpage)
+{
+}
#endif

static void collapse_huge_page(struct mm_struct *mm,
@@ -1936,8 +1944,10 @@ static void collapse_huge_page(struct mm_struct *mm,
if (!new_page)
return;

- if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)))
+ if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
+ khugepaged_cleanup_page(hpage);
return;
+ }

/*
* Prevent all access to pagetables with the exception of
@@ -2048,6 +2058,7 @@ out_up_write:
return;

out:
+ khugepaged_cleanup_page(hpage);
mem_cgroup_uncharge_page(new_page);
goto out_up_write;
}
--
1.7.7.6

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