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From: Liang Chen <liangchen.linux@gmail.com>
To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, hawk@kernel.org, ilias.apalodimas@linaro.org,
	linyunsheng@huawei.com
Cc: netdev@vger.kernel.org, linux-mm@kvack.org, jasowang@redhat.com,
	liangchen.linux@gmail.com
Subject: [PATCH net-next v7 2/4] page_pool: halve BIAS_MAX for multiple user references of a fragment
Date: Wed,  6 Dec 2023 18:54:17 +0800	[thread overview]
Message-ID: <20231206105419.27952-3-liangchen.linux@gmail.com> (raw)
In-Reply-To: <20231206105419.27952-1-liangchen.linux@gmail.com>

Referring to patch [1], in order to support multiple users referencing the
same fragment and prevent overflow from pp_ref_count growing, the initial
value of pp_ref_count is halved, leaving room for pp_ref_count to increment
before the page is drained.

[1]
https://lore.kernel.org/all/20211009093724.10539-3-linyunsheng@huawei.com/

Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Reviewed-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 net/core/page_pool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 106220b1f89c..436f7ffea7b4 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -26,7 +26,7 @@
 #define DEFER_TIME (msecs_to_jiffies(1000))
 #define DEFER_WARN_INTERVAL (60 * HZ)
 
-#define BIAS_MAX	LONG_MAX
+#define BIAS_MAX	(LONG_MAX >> 1)
 
 #ifdef CONFIG_PAGE_POOL_STATS
 /* alloc_stat_inc is intended to be used in softirq context */
-- 
2.31.1



  parent reply	other threads:[~2023-12-06 10:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-06 10:54 [PATCH net-next v7 0/4] skbuff: Optimize SKB coalescing for page pool Liang Chen
2023-12-06 10:54 ` [PATCH net-next v7 1/4] page_pool: transition to reference count management after page draining Liang Chen
2023-12-09  1:38   ` Jakub Kicinski
2023-12-11  3:31     ` Liang Chen
2023-12-06 10:54 ` Liang Chen [this message]
2023-12-06 10:54 ` [PATCH net-next v7 3/4] skbuff: Add a function to check if a page belongs to page_pool Liang Chen
2023-12-06 10:54 ` [PATCH net-next v7 4/4] skbuff: Optimization of SKB coalescing for page pool Liang Chen
2023-12-09  2:18   ` Mina Almasry
2023-12-11  3:38     ` Liang Chen
2023-12-11  4:21       ` Mina Almasry
2023-12-11 19:32         ` Jakub Kicinski
2023-12-11 20:07           ` Mina Almasry

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