| Message ID | 20250220110752.137639-1-jirislaby@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c180188ec02281126045414e90d08422a80f75b4 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: set the minimum for net_hotdata.netdev_budget_usecs | expand |
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Thu, 20 Feb 2025 12:07:52 +0100 you wrote: > Commit 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs > to enable softirq tuning") added a possibility to set > net_hotdata.netdev_budget_usecs, but added no lower bound checking. > > Commit a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") > made the *initial* value HZ-dependent, so the initial value is at least > 2 jiffies even for lower HZ values (2 ms for 1000 Hz, 8ms for 250 Hz, 20 > ms for 100 Hz). > > [...] Here is the summary with links: - net: set the minimum for net_hotdata.netdev_budget_usecs https://git.kernel.org/netdev/net/c/c180188ec022 You are awesome, thank you!
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index ad2741f1346a..c7769ee0d9c5 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -34,6 +34,7 @@ static int min_sndbuf = SOCK_MIN_SNDBUF; static int min_rcvbuf = SOCK_MIN_RCVBUF; static int max_skb_frags = MAX_SKB_FRAGS; static int min_mem_pcpu_rsv = SK_MEMORY_PCPU_RESERVE; +static int netdev_budget_usecs_min = 2 * USEC_PER_SEC / HZ; static int net_msg_warn; /* Unused, but still a sysctl */ @@ -587,7 +588,7 @@ static struct ctl_table net_core_table[] = { .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ZERO, + .extra1 = &netdev_budget_usecs_min, }, { .procname = "fb_tunnels_only_for_init_net",
Commit 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") added a possibility to set net_hotdata.netdev_budget_usecs, but added no lower bound checking. Commit a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") made the *initial* value HZ-dependent, so the initial value is at least 2 jiffies even for lower HZ values (2 ms for 1000 Hz, 8ms for 250 Hz, 20 ms for 100 Hz). But a user still can set improper values by a sysctl. Set .extra1 (the lower bound) for net_hotdata.netdev_budget_usecs to the same value as in the latter commit. That is to 2 jiffies. Fixes: a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org> Cc: Dmitry Yakunin <zeil@yandex-team.ru> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: David S. Miller <davem@davemloft.net> --- net/core/sysctl_net_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)