On 9/15/2024 4:37 PM, Jason Gunthorpe wrote:
On Sat, Sep 14, 2024 at 06:05:50AM -0700, Steve Sistare wrote:
diff --git a/mm/gup.c b/mm/gup.c
index 947881ff..f8f3f2a 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3720,3 +3720,21 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end,
return ret;
}
EXPORT_SYMBOL_GPL(memfd_pin_folios);
+
+/**
+ * repin_folio_unhugely() - repin a folio at small page granularity
+ * @folio: the folio to repin
+ * @npin: the number of pages pinned in the folio
+ *
+ * Given a huge page folio that is already pinned, and the number of small
+ * pages that are pinned in it, adjust the pincount to reflect small-page
+ * granularity. Each small page can later be unpinned individually.
+ */
I think the language choice here is probably not entirely consistent
with the rest of the code
Yes, a good name was not obvious to me, to I submitted a slightly flippant
name to generate some discussion :)
Maybe
folio_split_user_page_pin(folio, npages)
@npages: The new number of pages the folio pin reference should hold
Given a high order folio that is already pinned adjust the reference
count to allow unpin_user_page_range() and related to be called on a
the folio. npages is the number of pages that will be passed to a
future unpin_user_page_range().
Which anchors it in the purpose a little more
Thanks, I will use this if no one objects.
- Steve
The implementation looked OK to me
Jason
