| Message ID | 20240604042454.2012091-5-alexs@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | use folio in ksm | expand |
On 04.06.24 06:24, alexs@kernel.org wrote: > From: "Alex Shi (tencent)" <alexs@kernel.org> > > To replace pages_identical() func and further reduce the 'page' using in > try_to_merge_one_page function. > > Signed-off-by: Alex Shi (tencent) <alexs@kernel.org> > --- > include/linux/mm.h | 17 +++++++++++++++++ > mm/ksm.c | 2 +- > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 9849dfda44d4..2d1f16ffc6ac 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -4164,6 +4164,23 @@ static inline void setup_nr_node_ids(void) {} > > extern int memcmp_pages(struct page *page1, struct page *page2); > > +static inline int identical_folio(struct folio *folio1, struct folio *folio2) > +{ > + int i, nr1, nr2, ret = 0; > + > + nr1 = folio_nr_pages(folio1); > + nr2 = folio_nr_pages(folio2); > + if (nr1 != nr2) > + return 0; > + > + for (i = 0; i < nr1; i++) { > + ret = memcmp_pages(folio_page(folio1, i), folio_page(folio2, i)); > + if (ret) > + break; > + } > + > + return !ret; > +} We never get there with large folios. So handling large folios is completely unnecessary. Keep it simple: either VM_WARN_ON_ONCE when a large folio is passed, or simply return "false". Then, check only a single page.
diff --git a/include/linux/mm.h b/include/linux/mm.h index 9849dfda44d4..2d1f16ffc6ac 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4164,6 +4164,23 @@ static inline void setup_nr_node_ids(void) {} extern int memcmp_pages(struct page *page1, struct page *page2); +static inline int identical_folio(struct folio *folio1, struct folio *folio2) +{ + int i, nr1, nr2, ret = 0; + + nr1 = folio_nr_pages(folio1); + nr2 = folio_nr_pages(folio2); + if (nr1 != nr2) + return 0; + + for (i = 0; i < nr1; i++) { + ret = memcmp_pages(folio_page(folio1, i), folio_page(folio2, i)); + if (ret) + break; + } + + return !ret; +} static inline int pages_identical(struct page *page1, struct page *page2) { return !memcmp_pages(page1, page2); diff --git a/mm/ksm.c b/mm/ksm.c index 21bfa9bfb210..2e4790842515 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1527,7 +1527,7 @@ static int try_to_merge_one_page(struct vm_area_struct *vma, struct folio *folio if (!folio_test_dirty(folio)) folio_set_dirty(folio); err = 0; - } else if (pages_identical(page, kpage)) + } else if (identical_folio(folio, kfolio)) err = replace_page(vma, page, kpage, orig_pte); }