[PATCH v3] mm/page_alloc: Consolidate unlikely handling in page_expected_state

[PATCH v3] mm/page_alloc: Consolidate unlikely handling in page_expected_state

[Ye Liu]

From: Ye Liu <liuye@kylinos.cn>

Consolidates the handling of unlikely conditions in the
page_expected_state function, reducing code duplication and improving
readability.

Previously, the check_new_page_bad function contained logic to handle
__PG_HWPOISON flags, which was called from check_new_page. This patch
moves the handling of __PG_HWPOISON flags into the page_expected_state
function and removes the check_new_page_bad function. The check_new_page
function now directly calls bad_page if the page has unexpected flags.

This change simplifies the code by reducing the number of functions and
centralizing the unlikely condition handling in one place.

Signed-off-by: Ye Liu <liuye@kylinos.cn>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

---
V3: Delete 'This patch'.
V2: return true instead of false in the PageHWPoison branch.
---
---
 mm/page_alloc.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2842da893eea..e8b95c6a96c2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -903,6 +903,12 @@ static inline bool page_expected_state(struct page *page,
 			(page->flags & check_flags)))
 		return false;
 
+	if (unlikely(PageHWPoison(page))) {
+		/* Don't complain about hwpoisoned pages */
+		if (PageBuddy(page))
+			__ClearPageBuddy(page);
+	}
+
 	return true;
 }
 
@@ -1586,29 +1592,15 @@ static __always_inline void page_del_and_expand(struct zone *zone,
 	account_freepages(zone, -nr_pages, migratetype);
 }
 
-static void check_new_page_bad(struct page *page)
-{
-	if (unlikely(PageHWPoison(page))) {
-		/* Don't complain about hwpoisoned pages */
-		if (PageBuddy(page))
-			__ClearPageBuddy(page);
-		return;
-	}
-
-	bad_page(page,
-		 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
-}
-
 /*
  * This page is about to be returned from the page allocator
  */
 static bool check_new_page(struct page *page)
 {
-	if (likely(page_expected_state(page,
-				PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
+	if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_PREP)))
 		return false;
 
-	check_new_page_bad(page);
+	bad_page(page, page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
 	return true;
 }
 
-- 
2.25.1

Re: [PATCH v3] mm/page_alloc: Consolidate unlikely handling in page_expected_state

[Markus Elfring]

> Consolidates the handling of
…
> This change simplifies
…
> ---
> V3: Delete 'This patch'.

How good does such information fit to the wording requirement “imperative mood”?
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14#n94

…
> ---
> ---
>  mm/page_alloc.c | 24 ++++++++----------------

How do you think about to omit redundant marker lines?

Regards,
Markus

Re: [PATCH v3] mm/page_alloc: Consolidate unlikely handling in page_expected_state

[Ye Liu]

在 2025/3/26 16:48, Markus Elfring 写道:
>> Consolidates the handling of
> …
>> This change simplifies
> …
>> ---
>> V3: Delete 'This patch'.
> How good does such information fit to the wording requirement “imperative mood”?
> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14#n94

How about this?

Consolidate the handling of unlikely conditions in the page_expected_state
function to reduce code duplication and improve readability.

Move the logic for handling __PG_HWPOISON flags from the check_new_page_bad
function to the page_expected_state function, and remove check_new_page_bad.

Call bad_page directly from the check_new_page function if the page has
unexpected flags.
                                                                            
Simplify the code by reducing the number of functions and centralizing the
handling of unlikely conditions.

> …
>> ---
>> ---
>>  mm/page_alloc.c | 24 ++++++++----------------
> How do you think about to omit redundant marker lines?

---  delete this one？
---
 mm/page_alloc.c | 24 ++++++++----------------


like this ?

V2: return true instead of false in the PageHWPoison branch.
---
 mm/page_alloc.c | 24 ++++++++----------------


Thanks for pointing out the formatting issue.
I would like to get your approval on the above changes before I send patch v4.


> Regards,
> Markus

Re: [v3] mm/page_alloc: Consolidate unlikely handling in page_expected_state

[Markus Elfring]

>> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14#n94
>
> How about this?

I hope that such review can trigger improvements in change descriptions
for further patch versions.


> Consolidate the handling of unlikely conditions in the page_expected_state
> function to reduce code duplication and improve readability.
…

Would you like to append parentheses to any function names?

Regards,
Markus

Re: [v3] mm/page_alloc: Consolidate unlikely handling in page_expected_state

[Ye Liu]

在 2025/3/27 23:05, Markus Elfring 写道:
>>> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14#n94
>> How about this?
> I hope that such review can trigger improvements in change descriptions
> for further patch versions.
>
Thanks for the review and suggestion! I appreciate the feedback and will
improve the change descriptions in future patch versions.               

>> Consolidate the handling of unlikely conditions in the page_expected_state
>> function to reduce code duplication and improve readability.
> …
>
> Would you like to append parentheses to any function names?

I'll adjust accordingly.

Best regards,
Ye           

> Regards,
> Markus