diff mbox series

[net-next,v4,2/4] page_pool: halve BIAS_MAX for multiple user references of a fragment

Message ID 20231129031201.32014-3-liangchen.linux@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series skbuff: Optimize SKB coalescing for page pool | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/codegen success Generated files up to date
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1117 this patch: 1117
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 1143 this patch: 1143
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1144 this patch: 1144
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Liang Chen Nov. 29, 2023, 3:11 a.m. UTC 
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(-)
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Patch

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 */