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authorSong Liu <songliubraving@fb.com>2019-09-24 01:38:19 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-25 01:54:11 +0300
commit010c164a5fa7e169deab0a4d8211611f1930c1cd (patch)
treefb07bdd2cf844ccf1e1aaf6fc40e42399fb0dc19 /mm/util.c
parent87eaceb3faa59b9b4d940ec9554ce251325d83fe (diff)
downloadlinux-010c164a5fa7e169deab0a4d8211611f1930c1cd.tar.xz
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@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>
Diffstat (limited to 'mm/util.c')
-rw-r--r--mm/util.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index bab284d69c8c..37f7b6711514 100644
--- a/mm/util.c
+++ b/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;
+}