mm: move memcmp_pages() and pages_identical() (010c164a) · Commits · 戴 / test

Patch series "THP aware uprobe", v13. This patchset makes uprobe aware of THPs. Currently, when uprobe is attached to text on THP, the page is split by FOLL_SPLIT. As a result, uprobe eliminates the performance benefit of THP. This set makes uprobe THP-aware. Instead of FOLL_SPLIT, we introduces FOLL_SPLIT_PMD, which only split PMD for uprobe. After all uprobes within the THP are removed, the PTE-mapped pages are regrouped as huge PMD. This set (plus a few THP patches) is also available at https://github.com/liu-song-6/linux/tree/uprobe-thp This patch (of 6): Move memcmp_pages() to mm/util.c and pages_identical() to mm.h, so that we can use them in other files. Link: http://lkml.kernel.org/r/20190815164525.1848545-2-songliubraving@fb.com Signed-off-by:

Song Liu <songliubraving@fb.com> Acked-by:

Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by:

Oleg Nesterov <oleg@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <matthew.wilcox@oracle.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -2868,5 +2868,12 @@ void __init setup_nr_node_ids(void);
		static inline void setup_nr_node_ids(void) {}
		#endif

		extern int memcmp_pages(struct page page1, struct page page2);

		static inline int pages_identical(struct page page1, struct page page2)
		{
		return !memcmp_pages(page1, page2);
		}

		#endif /* __KERNEL__ */
		#endif /* _LINUX_MM_H */

mm/ksm.c

+0 −18

Original line number	Diff line number	Diff line
		@@ -1029,24 +1029,6 @@ static u32 calc_checksum(struct page *page)
		return checksum;
		}

		static int memcmp_pages(struct page page1, struct page page2)
		{
		char addr1, addr2;
		int ret;

		addr1 = kmap_atomic(page1);
		addr2 = kmap_atomic(page2);
		ret = memcmp(addr1, addr2, PAGE_SIZE);
		kunmap_atomic(addr2);
		kunmap_atomic(addr1);
		return ret;
		}

		static inline int pages_identical(struct page page1, struct page page2)
		{
		return !memcmp_pages(page1, page2);
		}

		static int write_protect_page(struct vm_area_struct vma, struct page page,
		pte_t *orig_pte)
		{

mm/util.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -783,3 +783,16 @@ out_mm:
		out:
		return res;
		}

		int memcmp_pages(struct page page1, struct page page2)
		{
		char addr1, addr2;
		int ret;

		addr1 = kmap_atomic(page1);
		addr2 = kmap_atomic(page2);
		ret = memcmp(addr1, addr2, PAGE_SIZE);
		kunmap_atomic(addr2);
		kunmap_atomic(addr1);
		return ret;
		}

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