Re: [PATCH net v3] net: Force inlining of checksum functions in net/checksum.h
From: Joe Perches <joe@perches.com>
Date: 2022-02-17 15:42:15
Also in:
linuxppc-dev, lkml
On Thu, 2022-02-17 at 13:19 +0100, Christophe Leroy wrote:
All functions defined as static inline in net/checksum.h are
meant to be inlined for performance reason.
But since commit ac7c3e4ff401 ("compiler: enable
CONFIG_OPTIMIZE_INLINING forcibly") the compiler is allowed to
uninline functions when it wants.
Fair enough in the general case, but for tiny performance critical
checksum helpers that's counter-productive.Thanks. Trivial style notes:
quoted hunk ↗ jump to hunk
diff --git a/include/net/checksum.h b/include/net/checksum.h
[]
quoted hunk ↗ jump to hunk
@@ -22,7 +22,7 @@ #include <asm/checksum.h> #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER -static inline +static __always_inline __wsum csum_and_copy_from_user (const void __user *src, void *dst, int len) {
__wsum might be better placed on the previous line. []
quoted hunk ↗ jump to hunk
@@ -45,7 +45,7 @@ static __inline__ __wsum csum_and_copy_to_user #endif #ifndef _HAVE_ARCH_CSUM_AND_COPY -static inline __wsum +static __always_inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
To be consistent with the location of the __wsum return value when splitting the function definitions across multiple lines. (like the below)
quoted hunk ↗ jump to hunk
@@ -88,42 +88,43 @@ static inline __wsum csum_shift(__wsum sum, int offset) return sum; } -static inline __wsum +static __always_inline __wsum csum_block_add(__wsum csum, __wsum csum2, int offset) { return csum_add(csum, csum_shift(csum2, offset)); } -static inline __wsum +static __always_inline __wsum csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len) { return csum_block_add(csum, csum2, offset); } -static inline __wsum +static __always_inline __wsum csum_block_sub(__wsum csum, __wsum csum2, int offset) { return csum_block_add(csum, ~csum2, offset); } -static inline __wsum csum_unfold(__sum16 n) +static __always_inline __wsum csum_unfold(__sum16 n) { return (__force __wsum)n; }
[]
-static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
+static __always_inline
+__wsum csum_partial_ext(const void *buff, int len, __wsum sum)
{
return csum_partial(buff, len, sum);
}And this __wsum could be moved too.
quoted hunk ↗ jump to hunk
@@ -150,15 +151,15 @@ void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
[]
-static inline __wsum remcsum_adjust(void *ptr, __wsum csum,
+static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum,
int start, int offset)
{
__sum16 *psum = (__sum16 *)(ptr + offset);And this one could be split like the above static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum, int start, int offset)