On Mon, Apr 24, 2017 at 11:41:51AM -0700, Dan Williams wrote:
> On Mon, Apr 24, 2017 at 11:25 AM, Kirill A. Shutemov
> <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
> > On Mon, Apr 24, 2017 at 09:01:58PM +0300, Kirill A. Shutemov wrote:
> >> On Mon, Apr 24, 2017 at 10:47:43AM -0700, Dan Williams wrote:
> >> I think it's still better to do it on page_ref_* level.
> >
> > Something like patch below? What do you think?
>
> From a quick glance, I think this looks like the right way to go.
Okay, but I still would like to remove manipulation with pgmap->ref from
hot path.
Can we just check that page_count() match our expectation on
devm_memremap_pages_release() instead of this?
I probably miss something in bigger picture, but would something like
patch work too? It seems work for the test case.
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a835edd2db34..695da2a19b4c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -762,19 +762,11 @@ static inline enum zone_type page_zonenum(const struct page *page)
}
#ifdef CONFIG_ZONE_DEVICE
-void get_zone_device_page(struct page *page);
-void put_zone_device_page(struct page *page);
static inline bool is_zone_device_page(const struct page *page)
{
return page_zonenum(page) == ZONE_DEVICE;
}
#else
-static inline void get_zone_device_page(struct page *page)
-{
-}
-static inline void put_zone_device_page(struct page *page)
-{
-}
static inline bool is_zone_device_page(const struct page *page)
{
return false;
@@ -790,9 +782,6 @@ static inline void get_page(struct page *page)
*/
VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page);
page_ref_inc(page);
-
- if (unlikely(is_zone_device_page(page)))
- get_zone_device_page(page);
}
static inline void put_page(struct page *page)
@@ -801,9 +790,6 @@ static inline void put_page(struct page *page)
if (put_page_testzero(page))
__put_page(page);
-
- if (unlikely(is_zone_device_page(page)))
- put_zone_device_page(page);
}
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 07e85e5229da..e542bb2f7ab0 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -182,18 +182,6 @@ struct page_map {
struct vmem_altmap altmap;
};
-void get_zone_device_page(struct page *page)
-{
- percpu_ref_get(page->pgmap->ref);
-}
-EXPORT_SYMBOL(get_zone_device_page);
-
-void put_zone_device_page(struct page *page)
-{
- put_dev_pagemap(page->pgmap);
-}
-EXPORT_SYMBOL(put_zone_device_page);
-
static void pgmap_radix_release(struct resource *res)
{
resource_size_t key, align_start, align_size, align_end;
@@ -237,12 +225,21 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
struct resource *res = &page_map->res;
resource_size_t align_start, align_size;
struct dev_pagemap *pgmap = &page_map->pgmap;
+ unsigned long pfn;
if (percpu_ref_tryget_live(pgmap->ref)) {
dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
percpu_ref_put(pgmap->ref);
}
+ for_each_device_pfn(pfn, page_map) {
+ struct page *page = pfn_to_page(pfn);
+
+ dev_WARN_ONCE(dev, page_count(page) != 1,
+ "%s: unexpected page count: %d!\n",
+ __func__, page_count(page));
+ }
+
/* pages are dead and unused, undo the arch mapping */
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(resource_size(res), SECTION_SIZE);
--
Kirill A. Shutemov
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
