On 10/31/19 11:35 AM, Ira Weiny wrote:

On Wed, Oct 30, 2019 at 03:49:13PM -0700, John Hubbard wrote:

...

quoted

+
+static void __remove_refs_from_head(struct page *page, int refs)
+{
+	/* Do a get_page() first, in case refs == page->_refcount */
+	get_page(page);
+	page_ref_sub(page, refs);
+	put_page(page);
+}

I wonder if this is better implemented as "put_compound_head()"?  To match the
try_get_compound_head() call below?

Hi Ira,

Good idea, I'll rename it to that.

quoted

+
+static int __huge_pt_done(struct page *head, int nr_recorded_pages, int *nr)
+{
+	*nr += nr_recorded_pages;
+	SetPageReferenced(head);
+	return 1;

When will this return anything but 1?

Never, but it saves a line at all four call sites, by having it return like that.

I could see how maybe people would prefer to just have it be a void function,
and return 1 directly at the call sites. Since this was a lower line count I
thought maybe it would be slightly better, but it's hard to say really.

thanks,

John Hubbard
NVIDIA