linux-kernel - [PATCH net-next v3 03/13] mm: page_frag: use free_unref

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Date: Wed, 8 May 2024 21:33:58 +0800
From: Yunsheng Lin <linyunsheng@...wei.com>
To: <davem@...emloft.net>, <kuba@...nel.org>, <pabeni@...hat.com>
CC: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Yunsheng Lin
	<linyunsheng@...wei.com>, Alexander Duyck <alexander.duyck@...il.com>, Andrew
 Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>
Subject: [PATCH net-next v3 03/13] mm: page_frag: use free_unref_page() to free page fragment

free_the_page() used by page_frag call free_unref_page() or
__free_pages_ok() depending on pcp_allowed_order(), as the
max order of page allocated for page_frag is 3, the checking
in pcp_allowed_order() is unnecessary.

So call free_unref_page() directly to free a page_frag page
to aovid the unnecessary checking.

As the free_the_page() is a static function in page_alloc.c,
using the new one also allow moving page_frag related code
to a new file in the next patch.

CC: Alexander Duyck <alexander.duyck@...il.com>
Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
---
 mm/page_alloc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 14d39f34d336..7adb29f8f364 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4693,6 +4693,9 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
 	gfp_t gfp = gfp_mask;
 
 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+	/* Ensure free_unref_page() can be used to free the page fragment */
+	BUILD_BUG_ON(PAGE_FRAG_CACHE_MAX_ORDER > PAGE_ALLOC_COSTLY_ORDER);
+
 	gfp_mask = (gfp_mask & ~__GFP_DIRECT_RECLAIM) |  __GFP_COMP |
 		   __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC;
 	page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
@@ -4722,7 +4725,7 @@ void __page_frag_cache_drain(struct page *page, unsigned int count)
 	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
 
 	if (page_ref_sub_and_test(page, count))
-		free_the_page(page, compound_order(page));
+		free_unref_page(page, compound_order(page));
 }
 EXPORT_SYMBOL(__page_frag_cache_drain);
 
@@ -4763,7 +4766,7 @@ void *__page_frag_alloc_align(struct page_frag_cache *nc,
 			goto refill;
 
 		if (unlikely(nc->pfmemalloc)) {
-			free_the_page(page, compound_order(page));
+			free_unref_page(page, compound_order(page));
 			goto refill;
 		}
 
@@ -4807,7 +4810,7 @@ void page_frag_free(void *addr)
 	struct page *page = virt_to_head_page(addr);
 
 	if (unlikely(put_page_testzero(page)))
-		free_the_page(page, compound_order(page));
+		free_unref_page(page, compound_order(page));
 }
 EXPORT_SYMBOL(page_frag_free);
 
-- 
2.33.0