diff mbox series

[net-next,2/8] vxlan: Read jiffies once when updating FDB 'used' time

Message ID 20250204145549.1216254-3-idosch@nvidia.com (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series vxlan: Age FDB entries based on Rx traffic | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
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: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
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: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 14 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
netdev/contest success net-next-2025-02-05--00-00 (tests: 886)

Commit Message

Ido Schimmel Feb. 4, 2025, 2:55 p.m. UTC 
Avoid two volatile reads in the data path. Instead, read jiffies once
and only if an FDB entry was found.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 drivers/net/vxlan/vxlan_core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

Eric Dumazet Feb. 4, 2025, 3:42 p.m. UTC | #1 
On Tue, Feb 4, 2025 at 3:56 PM Ido Schimmel <idosch@nvidia.com> wrote:
>
> Avoid two volatile reads in the data path. Instead, read jiffies once
> and only if an FDB entry was found.
>
> Reviewed-by: Petr Machata <petrm@nvidia.com>
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>

Reviewed-by: Eric Dumazet <edumazet@google.com>
Nikolay Aleksandrov Feb. 4, 2025, 4:36 p.m. UTC | #2 
On 2/4/25 16:55, Ido Schimmel wrote:
> Avoid two volatile reads in the data path. Instead, read jiffies once
> and only if an FDB entry was found.
> 
> Reviewed-by: Petr Machata <petrm@nvidia.com>
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> ---
>  drivers/net/vxlan/vxlan_core.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
diff mbox series

Patch

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 2f2c6606f719..676a93ce3a19 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -434,8 +434,12 @@  static struct vxlan_fdb *vxlan_find_mac(struct vxlan_dev *vxlan,
 	struct vxlan_fdb *f;
 
 	f = __vxlan_find_mac(vxlan, mac, vni);
-	if (f && READ_ONCE(f->used) != jiffies)
-		WRITE_ONCE(f->used, jiffies);
+	if (f) {
+		unsigned long now = jiffies;
+
+		if (READ_ONCE(f->used) != now)
+			WRITE_ONCE(f->used, now);
+	}
 
 	return f;
 }