diff mbox series

[net-next] ipv4: avoid quadratic behavior in FIB insertion of common address

Message ID 20240926100807.3790287-1-alexandre.ferrieux@orange.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net-next] ipv4: avoid quadratic behavior in FIB insertion of common address | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
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: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 3 maintainers not CCed: pabeni@redhat.com kuba@kernel.org dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 16 this patch: 16
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: 16 this patch: 16
netdev/checkpatch warning WARNING: From:/Signed-off-by: email address mismatch: 'From: Alexandre Ferrieux <alexandre.ferrieux@gmail.com>' != 'Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com>' WARNING: line length of 83 exceeds 80 columns
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
netdev/contest success net-next-2024-09-26--12-00 (tests: 760)

Commit Message

Alexandre Ferrieux Sept. 26, 2024, 10:08 a.m. UTC
Mix netns into all IPv4 FIB hashes to avoid massive collision
when inserting the same address in many netns.

Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com>
---
 net/ipv4/fib_semantics.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

Comments

Nicolas Dichtel Sept. 26, 2024, 10:19 a.m. UTC | #1
Le 26/09/2024 à 12:08, Alexandre Ferrieux a écrit :
> Mix netns into all IPv4 FIB hashes to avoid massive collision
> when inserting the same address in many netns.
> 
> Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com>
> ---
Please, wait 24 hours before send the v2:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/maintainer-netdev.rst#n394

Also, update the commit title with the version number, for example ([PATCH
net-next v2]).
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst#n666

And add a log explaining the changes.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst#n723


Regards,
Nicolas
Simon Horman Sept. 26, 2024, 3:43 p.m. UTC | #2
On Thu, Sep 26, 2024 at 12:08:07PM +0200, Alexandre Ferrieux wrote:
> Mix netns into all IPv4 FIB hashes to avoid massive collision
> when inserting the same address in many netns.
> 
> Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com>

Hi Alexandre,

Thanks for your updated patch.

net-next is currently closed for the v6.12 merge window. It should
reopen next week, after v6.12-rc1 has been released. Please repost
your patch, keeping in mind other feedback from Nicolas Dichtel after
it has reopned.

> ---
>  net/ipv4/fib_semantics.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
> index ba2df3d2ac15..e25c8bc56067 100644
> --- a/net/ipv4/fib_semantics.c
> +++ b/net/ipv4/fib_semantics.c
> @@ -347,11 +347,9 @@ static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
>  	return val;
>  }
>  
> -static unsigned int fib_info_hashfn_result(unsigned int val)
> +static unsigned int fib_info_hashfn_result(const struct net *net, unsigned int val)

Please line wrap the above so it fits within 80 columns, as is still
preferred by Networking code.

checkpatch can be run with an option to flag this.

>  {
> -	unsigned int mask = (fib_info_hash_size - 1);
> -
> -	return (val ^ (val >> 7) ^ (val >> 12)) & mask;
> +	return hash_32(val ^ net_hash_mix(net), fib_info_hash_bits);
>  }
>  
>  static inline unsigned int fib_info_hashfn(struct fib_info *fi)

...
diff mbox series

Patch

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index ba2df3d2ac15..e25c8bc56067 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -347,11 +347,9 @@  static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
 	return val;
 }
 
-static unsigned int fib_info_hashfn_result(unsigned int val)
+static unsigned int fib_info_hashfn_result(const struct net *net, unsigned int val)
 {
-	unsigned int mask = (fib_info_hash_size - 1);
-
-	return (val ^ (val >> 7) ^ (val >> 12)) & mask;
+	return hash_32(val ^ net_hash_mix(net), fib_info_hash_bits);
 }
 
 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
@@ -370,7 +368,7 @@  static inline unsigned int fib_info_hashfn(struct fib_info *fi)
 		} endfor_nexthops(fi)
 	}
 
-	return fib_info_hashfn_result(val);
+	return fib_info_hashfn_result(fi->fib_net, val);
 }
 
 /* no metrics, only nexthop id */
@@ -385,7 +383,7 @@  static struct fib_info *fib_find_info_nh(struct net *net,
 				 cfg->fc_protocol, cfg->fc_scope,
 				 (__force u32)cfg->fc_prefsrc,
 				 cfg->fc_priority);
-	hash = fib_info_hashfn_result(hash);
+	hash = fib_info_hashfn_result(net, hash);
 	head = &fib_info_hash[hash];
 
 	hlist_for_each_entry(fi, head, fib_hash) {