[PATCH] mm/secretmem: use a folio in secretmem_fault()

[PATCH] mm/secretmem: use a folio in secretmem_fault()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Saves three implicit call to compound_head().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 mm/secretmem.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 86442a15d12f..3afb5ad701e1 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -55,6 +55,7 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf)
 	gfp_t gfp = vmf->gfp_mask;
 	unsigned long addr;
 	struct page *page;
+	struct folio *folio;
 	vm_fault_t ret;
 	int err;
 
@@ -66,23 +67,24 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf)
 retry:
 	page = find_lock_page(mapping, offset);
 	if (!page) {
-		page = alloc_page(gfp | __GFP_ZERO);
-		if (!page) {
+		folio = folio_alloc(gfp | __GFP_ZERO, 0);
+		if (!folio) {
 			ret = VM_FAULT_OOM;
 			goto out;
 		}
 
+		page = &folio->page;
 		err = set_direct_map_invalid_noflush(page);
 		if (err) {
-			put_page(page);
+			folio_put(folio);
 			ret = vmf_error(err);
 			goto out;
 		}
 
-		__SetPageUptodate(page);
-		err = add_to_page_cache_lru(page, mapping, offset, gfp);
+		__folio_mark_uptodate(folio);
+		err = filemap_add_folio(mapping, folio, offset, gfp);
 		if (unlikely(err)) {
-			put_page(page);
+			folio_put(folio);
 			/*
 			 * If a split of large page was required, it
 			 * already happened when we marked the page invalid
-- 
2.25.1

Re: [PATCH] mm/secretmem: use a folio in secretmem_fault()

[Matthew Wilcox]

On Sat, Aug 12, 2023 at 09:58:35AM +0800, Peng Zhang wrote:
> From: ZhangPeng <zhangpeng362@huawei.com>
> 
> Saves three implicit call to compound_head().

I count four!

>  		if (err) {
> -			put_page(page);
> +			folio_put(folio);
>  			ret = vmf_error(err);

One.

>  
> -		__SetPageUptodate(page);
> -		err = add_to_page_cache_lru(page, mapping, offset, gfp);
> +		__folio_mark_uptodate(folio);
> +		err = filemap_add_folio(mapping, folio, offset, gfp);

Two, three.

>  		if (unlikely(err)) {
> -			put_page(page);
> +			folio_put(folio);

Four!

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Re: [PATCH] mm/secretmem: use a folio in secretmem_fault()

[zhangpeng (AS)]

On 2023/8/12 11:53, Matthew Wilcox wrote:

> On Sat, Aug 12, 2023 at 09:58:35AM +0800, Peng Zhang wrote:
>> From: ZhangPeng <zhangpeng362@huawei.com>
>>
>> Saves three implicit call to compound_head().
> I count four!
>
>>   		if (err) {
>> -			put_page(page);
>> +			folio_put(folio);
>>   			ret = vmf_error(err);
> One.
>
>>   
>> -		__SetPageUptodate(page);
>> -		err = add_to_page_cache_lru(page, mapping, offset, gfp);
>> +		__folio_mark_uptodate(folio);
>> +		err = filemap_add_folio(mapping, folio, offset, gfp);
> Two, three.
>
>>   		if (unlikely(err)) {
>> -			put_page(page);
>> +			folio_put(folio);
> Four!
>
> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Indeed. Thanks!

-- 
Best Regards,
Peng