On 2024/5/28 22:17, Lance Yang wrote:
Hi Kefeng,
On Tue, May 28, 2024 at 9:45 PM Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
Add a #MC variant of folio_copy() which uses copy_mc_highpage() to
support #MC handled during folio copy, it will be used in folio
migration soon.
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
include/linux/mm.h | 1 +
mm/util.c | 20 ++++++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 12bf20ebae5a..0c78d67f787d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1321,6 +1321,7 @@ void put_pages_list(struct list_head *pages);
void split_page(struct page *page, unsigned int order);
void folio_copy(struct folio *dst, struct folio *src);
+int folio_mc_copy(struct folio *dst, struct folio *src);
unsigned long nr_free_buffer_pages(void);
diff --git a/mm/util.c b/mm/util.c
index c9e519e6811f..9462dbf7ce02 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -828,6 +828,26 @@ void folio_copy(struct folio *dst, struct folio *src)
}
EXPORT_SYMBOL(folio_copy);
+int folio_mc_copy(struct folio *dst, struct folio *src)
+{
+ long nr = folio_nr_pages(src);
+ long i = 0;
+ int ret = 0;
+
+ for (;;) {
+ if (copy_mc_highpage(folio_page(dst, i), folio_page(src, i))) {
+ ret = -EFAULT;
+ break;
+ }
+ if (++i == nr)
+ break;
+ cond_resched();
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(folio_mc_copy);
The code below might be clearer:
+int folio_mc_copy(struct folio *dst, struct folio *src)
+{
+ long nr = folio_nr_pages(src);
+ long i = 0;
+
+ for (;;) {
+ if (copy_mc_highpage(folio_page(dst, i), folio_page(src, i)))
+ return -EFAULT;
+ if (++i == nr)
+ break;
+ cond_resched();
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(folio_mc_copy);
IMO, we can return the error code directly without needing to use the 'ret'.
Clearer, will update, thanks
Thanks,
Lance
+
int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;
int sysctl_overcommit_ratio __read_mostly = 50;
unsigned long sysctl_overcommit_kbytes __read_mostly;
--
2.27.0
