The patch titled
Subject: mm: move memcmp_pages() and pages_identical()
has been added to the -mm tree. Its filename is
mm-move-memcmp_pages-and-pages_identical.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-move-memcmp_pages-and-pages_identical.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-move-memcmp_pages-and-pages_identical.patch
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------------------------------------------------------
From: Song Liu <songliubraving@xxxxxx>
Subject: mm: move memcmp_pages() and pages_identical()
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@xxxxxx
Signed-off-by: Song Liu <songliubraving@xxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox <matthew.wilcox@xxxxxxxxxx>
Cc: William Kucharski <william.kucharski@xxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 7 +++++++
mm/ksm.c | 18 ------------------
mm/util.c | 13 +++++++++++++
3 files changed, 20 insertions(+), 18 deletions(-)
--- a/include/linux/mm.h~mm-move-memcmp_pages-and-pages_identical
+++ a/include/linux/mm.h
@@ -2910,5 +2910,12 @@ 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 */
--- a/mm/ksm.c~mm-move-memcmp_pages-and-pages_identical
+++ a/mm/ksm.c
@@ -1029,24 +1029,6 @@ static u32 calc_checksum(struct page *pa
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)
{
--- a/mm/util.c~mm-move-memcmp_pages-and-pages_identical
+++ a/mm/util.c
@@ -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;
+}
_
Patches currently in -mm which might be from songliubraving@xxxxxx are
filemap-check-compound_headpage-mapping-in-filemap_fault.patch
filemap-check-compound_headpage-mapping-in-pagecache_get_page.patch
filemap-update-offset-check-in-filemap_fault.patch
mmthp-stats-for-file-backed-thp.patch
khugepaged-rename-collapse_shmem-and-khugepaged_scan_shmem.patch
mmthp-add-read-only-thp-support-for-non-shmem-fs.patch
mmthp-add-read-only-thp-support-for-non-shmem-fs-fix.patch
mmthp-add-read-only-thp-support-for-non-shmem-fs-fix-2.patch
mmthp-avoid-writes-to-file-with-thp-in-pagecache.patch
mm-move-memcmp_pages-and-pages_identical.patch
uprobe-use-original-page-when-all-uprobes-are-removed.patch
mm-thp-introduce-foll_split_pmd.patch
uprobe-use-foll_split_pmd-instead-of-foll_split.patch
khugepaged-enable-collapse-pmd-for-pte-mapped-thp.patch
uprobe-collapse-thp-pmd-after-removing-all-uprobes.patch
