Re: [Nouveau] [PATCH 09/27] mm: generalize the pgmap based page_free infrastructure

[Logan Gunthorpe]

On 2022-02-10 12:28 a.m., Christoph Hellwig wrote:
> Key off on the existence of ->page_free to prepare for adding support for
> more pgmap types that are device managed and thus need the free callback.
> 
> Signed-off-by: Christoph Hellwig 

Great! This makes my patch simpler.

Reviewed-by: Logan Gunthorpe 


> ---
>  mm/memremap.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/memremap.c b/mm/memremap.c
> index fef5734d5e4933..e00ffcdba7b632 100644
> --- a/mm/memremap.c
> +++ b/mm/memremap.c
> @@ -452,7 +452,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
>  
>  void free_zone_device_page(struct page *page)
>  {
> - if (WARN_ON_ONCE(!is_device_private_page(page)))
> + if (WARN_ON_ONCE(!page->pgmap->ops || !page->pgmap->ops->page_free))
>   return;
>  
>   __ClearPageWaiters(page);
> @@ -460,7 +460,7 @@ void free_zone_device_page(struct page *page)
>   mem_cgroup_uncharge(page_folio(page));
>  
>   /*
> -  * When a device_private page is freed, the page->mapping field
> +  * When a device managed page is freed, the page->mapping field
>* may still contain a (stale) mapping value. For example, the
>* lower bits of page->mapping may still identify the page as an
>* anonymous page. Ultimately, this entire field is just stale
> 

[Nouveau] [PATCH 09/27] mm: generalize the pgmap based page_free infrastructure

[Christoph Hellwig]

Key off on the existence of ->page_free to prepare for adding support for
more pgmap types that are device managed and thus need the free callback.

Signed-off-by: Christoph Hellwig 
---
 mm/memremap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memremap.c b/mm/memremap.c
index fef5734d5e4933..e00ffcdba7b632 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -452,7 +452,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);
 
 void free_zone_device_page(struct page *page)
 {
-   if (WARN_ON_ONCE(!is_device_private_page(page)))
+   if (WARN_ON_ONCE(!page->pgmap->ops || !page->pgmap->ops->page_free))
return;
 
__ClearPageWaiters(page);
@@ -460,7 +460,7 @@ void free_zone_device_page(struct page *page)
mem_cgroup_uncharge(page_folio(page));
 
/*
-* When a device_private page is freed, the page->mapping field
+* When a device managed page is freed, the page->mapping field
 * may still contain a (stale) mapping value. For example, the
 * lower bits of page->mapping may still identify the page as an
 * anonymous page. Ultimately, this entire field is just stale
-- 
2.30.2