diff mbox series

[net-next,v7,2/6] net: Add control functions for irq suspension

Message ID 20241108023912.98416-3-jdamato@fastly.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Suspend IRQs during application busy periods | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; GEN HAS DIFF 2 files changed, 19 insertions(+);
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: 5 this patch: 5
netdev/build_tools success Errors and warnings before: 2 (+0) this patch: 2 (+0)
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 5 this patch: 5
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: 133 this patch: 133
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 54 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 79 this patch: 79
netdev/source_inline success Was 0 now: 0

Commit Message

Joe Damato Nov. 8, 2024, 2:38 a.m. UTC 
From: Martin Karsten <mkarsten@uwaterloo.ca>

The napi_suspend_irqs routine bootstraps irq suspension by elongating
the defer timeout to irq_suspend_timeout.

The napi_resume_irqs routine effectively cancels irq suspension by
forcing the napi to be scheduled immediately.

Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
 v7:
  - This is now patch 2 instead of patch 3; patch 2 from v6 was dropped.

 v1 -> v2:
   - Added a comment to napi_resume_irqs.

 include/net/busy_poll.h |  3 +++
 net/core/dev.c          | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

Comments

Jakub Kicinski Nov. 8, 2024, 4:21 a.m. UTC | #1 
On Fri,  8 Nov 2024 02:38:58 +0000 Joe Damato wrote:
> +EXPORT_SYMBOL(napi_suspend_irqs);

One more nit after all.. please drop the exports, epoll code can't
be a module. Feel free to repost without the 24h wait.
Joe Damato Nov. 8, 2024, 4:56 a.m. UTC | #2 
On Thu, Nov 07, 2024 at 08:21:19PM -0800, Jakub Kicinski wrote:
> On Fri,  8 Nov 2024 02:38:58 +0000 Joe Damato wrote:
> > +EXPORT_SYMBOL(napi_suspend_irqs);
> 
> One more nit after all.. please drop the exports, epoll code can't
> be a module. Feel free to repost without the 24h wait.

Done. Thanks for catching that and letting me re-send so quickly.
diff mbox series

Patch

diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h
index f03040baaefd..c858270141bc 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -52,6 +52,9 @@  void napi_busy_loop_rcu(unsigned int napi_id,
 			bool (*loop_end)(void *, unsigned long),
 			void *loop_end_arg, bool prefer_busy_poll, u16 budget);
 
+void napi_suspend_irqs(unsigned int napi_id);
+void napi_resume_irqs(unsigned int napi_id);
+
 #else /* CONFIG_NET_RX_BUSY_POLL */
 static inline unsigned long net_busy_loop_on(void)
 {
diff --git a/net/core/dev.c b/net/core/dev.c
index 4d910872963f..81f5e4175a6a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6507,6 +6507,45 @@  void napi_busy_loop(unsigned int napi_id,
 }
 EXPORT_SYMBOL(napi_busy_loop);
 
+void napi_suspend_irqs(unsigned int napi_id)
+{
+	struct napi_struct *napi;
+
+	rcu_read_lock();
+	napi = napi_by_id(napi_id);
+	if (napi) {
+		unsigned long timeout = napi_get_irq_suspend_timeout(napi);
+
+		if (timeout)
+			hrtimer_start(&napi->timer, ns_to_ktime(timeout),
+				      HRTIMER_MODE_REL_PINNED);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(napi_suspend_irqs);
+
+void napi_resume_irqs(unsigned int napi_id)
+{
+	struct napi_struct *napi;
+
+	rcu_read_lock();
+	napi = napi_by_id(napi_id);
+	if (napi) {
+		/* If irq_suspend_timeout is set to 0 between the call to
+		 * napi_suspend_irqs and now, the original value still
+		 * determines the safety timeout as intended and napi_watchdog
+		 * will resume irq processing.
+		 */
+		if (napi_get_irq_suspend_timeout(napi)) {
+			local_bh_disable();
+			napi_schedule(napi);
+			local_bh_enable();
+		}
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(napi_resume_irqs);
+
 #endif /* CONFIG_NET_RX_BUSY_POLL */
 
 static void __napi_hash_add_with_id(struct napi_struct *napi,