diff mbox series

[net-next,v3,2/3] eventpoll: Add per-epoll busy poll packet budget

Message ID 20240125225704.12781-3-jdamato@fastly.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Per epoll context busy poll support | 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; 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: 1069 this patch: 1069
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 0 of 0 maintainers
netdev/build_clang success Errors and warnings before: 1082 this patch: 1082
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: 1087 this patch: 1087
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 30 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

Commit Message

Joe Damato Jan. 25, 2024, 10:56 p.m. UTC
When using epoll-based busy poll, the packet budget is hardcoded to
BUSY_POLL_BUDGET (8). Users may desire larger busy poll budgets, which
can potentially increase throughput when busy polling under high network
load.

Other busy poll methods allow setting the busy poll budget via
SO_BUSY_POLL_BUDGET, but epoll-based busy polling uses a hardcoded
value.

Fix this edge case by adding support for a per-epoll context busy poll
packet budget. If not specified, the default value (BUSY_POLL_BUDGET) is
used.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 fs/eventpoll.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4503fec01278..40bd97477b91 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -229,6 +229,8 @@  struct eventpoll {
 	unsigned int napi_id;
 	/* busy poll timeout */
 	u64 busy_poll_usecs;
+	/* busy poll packet budget */
+	u16 busy_poll_budget;
 #endif
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -437,10 +439,14 @@  static bool ep_busy_loop_end(void *p, unsigned long start_time)
 static bool ep_busy_loop(struct eventpoll *ep, int nonblock)
 {
 	unsigned int napi_id = READ_ONCE(ep->napi_id);
+	u16 budget = READ_ONCE(ep->busy_poll_budget);
+
+	if (!budget)
+		budget = BUSY_POLL_BUDGET;
 
 	if ((napi_id >= MIN_NAPI_ID) && ep_busy_loop_on(ep)) {
 		napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false,
-			       BUSY_POLL_BUDGET);
+			       budget);
 		if (ep_events_available(ep))
 			return true;
 		/*
@@ -2098,6 +2104,7 @@  static int do_epoll_create(int flags)
 	}
 #ifdef CONFIG_NET_RX_BUSY_POLL
 	ep->busy_poll_usecs = 0;
+	ep->busy_poll_budget = 0;
 #endif
 	ep->file = file;
 	fd_install(fd, file);