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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2013-11-14 14:31:51 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-15 09:32:20 +0900
commit49076ec2ccaf68610aa03d96bced9a6694b93ca1 (patch)
tree876564edb5cd164c7f9eaf39008f8f01fb164db6 /mm/memory.c
parentf820e2805c7acb157a78438d07e47f4fc57fe679 (diff)
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mm: dynamically allocate page->ptl if it cannot be embedded to struct page
If split page table lock is in use, we embed the lock into struct page of table's page. We have to disable split lock, if spinlock_t is too big be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC enabled. This patch add support for dynamic allocation of split page table lock if we can't embed it to struct page. page->ptl is unsigned long now and we use it as spinlock_t if sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to spinlock_t. The spinlock_t allocated in pgtable_page_ctor() for PTE table and in pgtable_pmd_page_ctor() for PMD table. All other helpers converted to support dynamically allocated page->ptl. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index d05c6b10e926..24ffae2a530e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4270,3 +4270,22 @@ void copy_user_huge_page(struct page *dst, struct page *src,
}
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
+
+#if USE_SPLIT_PTE_PTLOCKS
+bool __ptlock_alloc(struct page *page)
+{
+ spinlock_t *ptl;
+
+ ptl = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
+ if (!ptl)
+ return false;
+ page->ptl = (unsigned long)ptl;
+ return true;
+}
+
+void __ptlock_free(struct page *page)
+{
+ if (sizeof(spinlock_t) > sizeof(page->ptl))
+ kfree((spinlock_t *)page->ptl);
+}
+#endif