On 18.12.23 17:07, Ryan Roberts wrote:
On 11/12/2023 15:56, David Hildenbrand wrote:
Let's factor it out to prepare for reuse as we convert
page_add_anon_rmap() to folio_add_anon_rmap_[pte|ptes|pmd]().
Make the compiler always special-case on the granularity by using
__always_inline.
Reviewed-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
mm/rmap.c | 81 ++++++++++++++++++++++++++++++-------------------------
1 file changed, 45 insertions(+), 36 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index 2ff2f11275e5..c5761986a411 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1157,6 +1157,49 @@ int folio_total_mapcount(struct folio *folio)
return mapcount;
}
+static __always_inline unsigned int __folio_add_rmap(struct folio *folio,
+ struct page *page, int nr_pages, enum rmap_mode mode,
+ unsigned int *nr_pmdmapped)
+{
+ atomic_t *mapped = &folio->_nr_pages_mapped;
+ int first, nr = 0;
+
+ __folio_rmap_sanity_checks(folio, page, nr_pages, mode);
+
+ /* Is page being mapped by PTE? Is this its first map to be added? */
I suspect this comment is left over from the old version? It sounds a bit odd in
its new context.
In this patch, I'm just moving the code, so it would have to be dropped
in a previous patch.
I'm happy to drop all these comments in previous patches.
+ switch (mode) {
+ case RMAP_MODE_PTE:
+ do {
+ first = atomic_inc_and_test(&page->_mapcount);
+ if (first && folio_test_large(folio)) {
+ first = atomic_inc_return_relaxed(mapped);
+ first = (first < COMPOUND_MAPPED);
+ }
+
+ if (first)
+ nr++;
+ } while (page++, --nr_pages > 0);
+ break;
+ case RMAP_MODE_PMD:
+ first = atomic_inc_and_test(&folio->_entire_mapcount);
+ if (first) {
+ nr = atomic_add_return_relaxed(COMPOUND_MAPPED, mapped);
+ if (likely(nr < COMPOUND_MAPPED + COMPOUND_MAPPED)) {
+ *nr_pmdmapped = folio_nr_pages(folio);
+ nr = *nr_pmdmapped - (nr & FOLIO_PAGES_MAPPED);
+ /* Raced ahead of a remove and another add? */
+ if (unlikely(nr < 0))
+ nr = 0;
+ } else {
+ /* Raced ahead of a remove of COMPOUND_MAPPED */
+ nr = 0;
+ }
+ }
+ break;
+ }
+ return nr;
+}
+
/**
* folio_move_anon_rmap - move a folio to our anon_vma
* @folio: The folio to move to our anon_vma
@@ -1380,45 +1423,11 @@ static __always_inline void __folio_add_file_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
enum rmap_mode mode)
{
- atomic_t *mapped = &folio->_nr_pages_mapped;
- unsigned int nr_pmdmapped = 0, first;
- int nr = 0;
+ unsigned int nr, nr_pmdmapped = 0;
You're still being inconsistent with signed/unsigned here. Is there a reason
these can't be signed like nr_pages in the interface?
I can turn them into signed values.
Personally, I think it's misleading to use "signed" for values that have
absolutely no meaning for negative meaning. But sure, we can be
consistent, at least in rmap code.
--
Cheers,
David / dhildenb
