From nobody Tue Sep 9 16:21:03 2025 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.3]) by smtp.subspace.kernel.org (Postfix) with ESMTP id F28991EB193; Sat, 6 Sep 2025 17:30:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.3 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757179849; cv=none; b=On8Dl42LLeqZdYwkxLt/k+B6o5mUb9i+TLxi5nmIjbEvsg72VMStFAADfvm3clZIZK1IOAXX56TnwYMaB1iP5f0/1Ogr779PXlqXlIiQFDb/Oilj69Bn+PpGyJjRQ8ixd7tzcxdnyX4qJ3zl3tkzruPyEvJGL/u910luKzv39SE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757179849; c=relaxed/simple; bh=k/e+GxLzaLWHXW4ybilZi/DyVV97aJCPpbq+l5+E5pM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OIgrA2L7yjDvFZ8HKGorhT3t56f9ba96FkEvzxfw4iHe8UhqlrHMWca5+QPj7XYMIvht7RBpGLzZ2dnA2xaiedPL5CeDdNIo08b2hLu0WXJ34xO1s+a6hI/UY5aWLJrSBKID+XNC0E1SXNe3kJZW0zkDPXxF+W/6GHcXUwg4lNk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=DDL+Ec0w; arc=none smtp.client-ip=117.135.210.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="DDL+Ec0w" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=JJ aR7eeM4R1xw7uwZoMzi6TmSyd6BYr9d5jerFk/sIU=; b=DDL+Ec0wWWOGi0407M YZnQOwGRQHs7YJyvTm545MPjwoGJ4Ol8cv2gw7sph7+Hj5wLSw5PHJQOVRC/Efe2 B9xLPNjqlFmq1sPznKRWp7xnDvs/F5UwUtrsKZHrn9nE5Bu1gSC4CszoDE25oxY8 qk4MXTZ3sCNyN57eVedbO6new= Received: from zhaoxin-MS-7E12.. (unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wD3f+Wbb7xoubfqGQ--.36512S3; Sun, 07 Sep 2025 01:30:07 +0800 (CST) From: Xin Zhao To: willemdebruijn.kernel@gmail.com, kerneljasonxing@gmail.com, edumazet@google.com, ferenc@fejes.dev Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Xin Zhao Subject: [PATCH net-next v11 1/2] net: af_packet: remove last_kactive_blk_num field Date: Sun, 7 Sep 2025 01:30:00 +0800 Message-Id: <20250906173001.3656356-2-jackzxcui1989@163.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250906173001.3656356-1-jackzxcui1989@163.com> References: <20250906173001.3656356-1-jackzxcui1989@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wD3f+Wbb7xoubfqGQ--.36512S3 X-Coremail-Antispam: 1Uf129KBjvJXoWxurWUJrWxAFWkXFW5Ar1kZrb_yoWruF4xpF WYkw13Gw1DGr42gw4xZwnrZr15Ww45XFyUGr98Jw4fAasxJryaya9F9ry7WFyFyFZ3Zay2 qrs5t345Cw1DJrDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0z_E_MUUUUUU= X-CM-SenderInfo: pmdfy650fxxiqzyzqiywtou0bp/1tbiJQ3ACmi8a+ReEgABs0 Content-Type: text/plain; charset="utf-8" kactive_blk_num (K) is only incremented on block close. In timer callback prb_retire_rx_blk_timer_expired, except delete_blk_timer is true, last_kactive_blk_num (L) is set to match kactive_blk_num (K) in all cases. L is also set to match K in prb_open_block. The only case K not equal to L is when scheduled by tpacket_rcv and K is just incremented on block close but no new block could be opened, so that it does not call prb_open_block in prb_dispatch_next_block. This patch modifies the prb_retire_rx_blk_timer_expired function by simply=20 removing the check for L =3D=3D K. This patch just provides another checkpo= int to thaw the might-be-frozen block in any case. It doesn't have any effect because __packet_lookup_frame_in_block() has the same logic and does it again without this patch when detecting the ring is frozen. The patch only advances checking the status of the ring. Suggested-by: Willem de Bruijn Reviewed-by: Willem de Bruijn Reviewed-by: Jason Xing Link: https://lore.kernel.org/all/20250831100822.1238795-1-jackzxcui1989@16= 3.com/ Signed-off-by: Xin Zhao --- net/packet/af_packet.c | 60 ++++++++++++++++++++---------------------- net/packet/internal.h | 6 ----- 2 files changed, 28 insertions(+), 38 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index a7017d7f0..d4eb4a4fe 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -669,7 +669,6 @@ static void init_prb_bdqc(struct packet_sock *po, p1->knum_blocks =3D req_u->req3.tp_block_nr; p1->hdrlen =3D po->tp_hdrlen; p1->version =3D po->tp_version; - p1->last_kactive_blk_num =3D 0; po->stats.stats3.tp_freeze_q_cnt =3D 0; if (req_u->req3.tp_retire_blk_tov) p1->retire_blk_tov =3D req_u->req3.tp_retire_blk_tov; @@ -693,7 +692,6 @@ static void _prb_refresh_rx_retire_blk_timer(struct tpa= cket_kbdq_core *pkc) { mod_timer(&pkc->retire_blk_timer, jiffies + pkc->tov_in_jiffies); - pkc->last_kactive_blk_num =3D pkc->kactive_blk_num; } =20 /* @@ -750,38 +748,36 @@ static void prb_retire_rx_blk_timer_expired(struct ti= mer_list *t) write_unlock(&pkc->blk_fill_in_prog_lock); } =20 - if (pkc->last_kactive_blk_num =3D=3D pkc->kactive_blk_num) { - if (!frozen) { - if (!BLOCK_NUM_PKTS(pbd)) { - /* An empty block. Just refresh the timer. */ - goto refresh_timer; - } - prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO); - if (!prb_dispatch_next_block(pkc, po)) - goto refresh_timer; - else - goto out; + if (!frozen) { + if (!BLOCK_NUM_PKTS(pbd)) { + /* An empty block. Just refresh the timer. */ + goto refresh_timer; + } + prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO); + if (!prb_dispatch_next_block(pkc, po)) + goto refresh_timer; + else + goto out; + } else { + /* Case 1. Queue was frozen because user-space was + * lagging behind. + */ + if (prb_curr_blk_in_use(pbd)) { + /* + * Ok, user-space is still behind. + * So just refresh the timer. + */ + goto refresh_timer; } else { - /* Case 1. Queue was frozen because user-space was - * lagging behind. + /* Case 2. queue was frozen,user-space caught up, + * now the link went idle && the timer fired. + * We don't have a block to close.So we open this + * block and restart the timer. + * opening a block thaws the queue,restarts timer + * Thawing/timer-refresh is a side effect. */ - if (prb_curr_blk_in_use(pbd)) { - /* - * Ok, user-space is still behind. - * So just refresh the timer. - */ - goto refresh_timer; - } else { - /* Case 2. queue was frozen,user-space caught up, - * now the link went idle && the timer fired. - * We don't have a block to close.So we open this - * block and restart the timer. - * opening a block thaws the queue,restarts timer - * Thawing/timer-refresh is a side effect. - */ - prb_open_block(pkc, pbd); - goto out; - } + prb_open_block(pkc, pbd); + goto out; } } =20 diff --git a/net/packet/internal.h b/net/packet/internal.h index 1e743d031..d367b9f93 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -24,12 +24,6 @@ struct tpacket_kbdq_core { unsigned short kactive_blk_num; unsigned short blk_sizeof_priv; =20 - /* last_kactive_blk_num: - * trick to see if user-space has caught up - * in order to avoid refreshing timer when every single pkt arrives. - */ - unsigned short last_kactive_blk_num; - char *pkblk_start; char *pkblk_end; int kblk_size; --=20 2.34.1 From nobody Tue Sep 9 16:21:03 2025 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.4]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D12C82F0683; Sat, 6 Sep 2025 17:30:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757179852; cv=none; b=QdTSd5rGm1M+tXAm/xllbQGvqhYD2Le/RwUAYBqFOIBptT7drQFiY4fkUyUwmocRP/AdMgPfNXAa0nZq9IPWDQho7DCQPFwt5dYsn2qN3/U0kDhLX43N51KYGkixD0GDRftd6pSOXvYjQgwPHKiOCp1ZviQ0SSnR6DHQQXui0m4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757179852; c=relaxed/simple; bh=q9NCHowKlKz6nHsCo7VvMLD3zB7e1flipmhMfqKGZ1A=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=JExdL95ORCoBPBiKz4rX789Z30GnTpBhv9sD7NhMZ0tUNwcaPtr+QTIauI/AXjPbUNrBFgj8l8UXiMJ7XeXwFDrbbroW33G+9EXO0bIPWVbThM6PMpJs0pQY4gKAiqpUrHZ8vFV+kaeORFTeA73ihSYdPsna7bViieTa9JabsEE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=UrqIteyU; arc=none smtp.client-ip=117.135.210.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="UrqIteyU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=+U 177AoO1vSpOWYROAnxcIatY5dh9vLhXesL9jQaj3M=; b=UrqIteyU4wDu8XTrO7 6OvTa0SEJMi892lOezfaLii+ACalD+tJDuAtKdCongqUB1GNiMiaOLmCSvr+MMMK /eEC2KHpkyhAJZxABU3O2lnZPVCMQ4SUEYwtdIjqfSqgzVaVdUubdJ3lNhlzQhzY g0jX26DTY+qtaNQ115V6sNlS8= Received: from zhaoxin-MS-7E12.. (unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wD3f+Wbb7xoubfqGQ--.36512S4; Sun, 07 Sep 2025 01:30:10 +0800 (CST) From: Xin Zhao To: willemdebruijn.kernel@gmail.com, kerneljasonxing@gmail.com, edumazet@google.com, ferenc@fejes.dev Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Xin Zhao Subject: [PATCH net-next v11 2/2] net: af_packet: Use hrtimer to do the retire operation Date: Sun, 7 Sep 2025 01:30:01 +0800 Message-Id: <20250906173001.3656356-3-jackzxcui1989@163.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250906173001.3656356-1-jackzxcui1989@163.com> References: <20250906173001.3656356-1-jackzxcui1989@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wD3f+Wbb7xoubfqGQ--.36512S4 X-Coremail-Antispam: 1Uf129KBjvAXoW3uw4xCFyUGrykCr4DtF1DJrb_yoW8JryfCo Z3XrZ8Cr4ktry7J3ykCryjkFy7u3yDtr15Xr4F9ryku3Z0vr15uw1fJay3Z3yfuw1Sk3Wk AFy0g34rXF4Dtr1rn29KB7ZKAUJUUUU8529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UbIYCTnIWIevJa73UjIFyTuYvj4RumhFDUUUU X-CM-SenderInfo: pmdfy650fxxiqzyzqiywtou0bp/1tbiRxXACmi8bM1FVgAAs+ Content-Type: text/plain; charset="utf-8" In a system with high real-time requirements, the timeout mechanism of ordinary timers with jiffies granularity is insufficient to meet the demands for real-time performance. Meanwhile, the optimization of CPU usage with af_packet is quite significant. Use hrtimer instead of timer to help compensate for the shortcomings in real-time performance. In HZ=3D100 or HZ=3D250 system, the update of TP_STATUS_USER is not real-ti= me enough, with fluctuations reaching over 8ms (on a system with HZ=3D250). This is unacceptable in some high real-time systems that require timely processing of network packets. By replacing it with hrtimer, if a timeout of 2ms is set, the update of TP_STATUS_USER can be stabilized to within 3 ms. Reviewed-by: Willem de Bruijn Reviewed-by: Jason Xing Link: https://lore.kernel.org/all/20250831100822.1238795-1-jackzxcui1989@16= 3.com/ Signed-off-by: Xin Zhao --- Changes in v11: - structure tpacket_kbdq_core needs a new organization as suggested by Jason Xing. - Change the comments of prb_retire_rx_blk_timer_expired and prb_open_block as suggested by Jason Xing. Changes in v9: - Remove the function prb_setup_retire_blk_timer and move hrtimer setup and= start logic into function init_prb_bdqc as suggested by Willem de Bruijn. - Remove 'refresh_timer:' label which is not needed while I change goto log= ic to if-else implementation. Changes in v8: - Delete delete_blk_timer field, as suggested by Willem de Bruijn, hrtimer_cancel will check and wait until the timer callback return and en= sure enter enter callback again. - Simplify the logic related to setting timeout, as suggestd by Willem de B= ruijn. Currently timer callback just restarts itself unconditionally, so delete = the 'out:' label, do not forward hrtimer in prb_open_block, call hrtimer_forw= ard_now directly and always return HRTIMER_RESTART. The only special case is when prb_open_block is called from tpacket_rcv. = That would set the timeout further into the future than the already queued tim= er. An earlier timeout is not problematic. No need to add complexity to avoid= that. Changes in v7: - Only update the hrtimer expire time within the hrtimer callback. When the callback return, without sk_buff_head lock protection, __run_hrt= imer will enqueue the timer if return HRTIMER_RESTART. Setting the hrtimer expires = while enqueuing a timer may cause chaos in the hrtimer red-black tree. Changes in v2: - Drop the tov_in_msecs field of tpacket_kbdq_core added by the patch as suggested by Willem de Bruijn. Changes in v1: - Do not add another config for the current changes as suggested by Eric Dumazet. - Mention the beneficial cases 'HZ=3D100 or HZ=3D250' and performance detai= ls in the changelog as suggested by Eric Dumazet and Ferenc Fejes. - Delete the 'pkc->tov_in_msecs =3D=3D 0' bounds check which is not necessa= ry as suggested by Willem de Bruijn. --- net/packet/af_packet.c | 108 ++++++++++++----------------------------- net/packet/diag.c | 2 +- net/packet/internal.h | 10 ++-- 3 files changed, 38 insertions(+), 82 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index d4eb4a4fe..d55528776 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -203,8 +203,7 @@ static void prb_retire_current_block(struct tpacket_kbd= q_core *, static int prb_queue_frozen(struct tpacket_kbdq_core *); static void prb_open_block(struct tpacket_kbdq_core *, struct tpacket_block_desc *); -static void prb_retire_rx_blk_timer_expired(struct timer_list *); -static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *); +static enum hrtimer_restart prb_retire_rx_blk_timer_expired(struct hrtimer= *); static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hd= r *); static void prb_clear_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hdr *); @@ -579,33 +578,13 @@ static __be16 vlan_get_protocol_dgram(const struct sk= _buff *skb) return proto; } =20 -static void prb_del_retire_blk_timer(struct tpacket_kbdq_core *pkc) -{ - timer_delete_sync(&pkc->retire_blk_timer); -} - static void prb_shutdown_retire_blk_timer(struct packet_sock *po, struct sk_buff_head *rb_queue) { struct tpacket_kbdq_core *pkc; =20 pkc =3D GET_PBDQC_FROM_RB(&po->rx_ring); - - spin_lock_bh(&rb_queue->lock); - pkc->delete_blk_timer =3D 1; - spin_unlock_bh(&rb_queue->lock); - - prb_del_retire_blk_timer(pkc); -} - -static void prb_setup_retire_blk_timer(struct packet_sock *po) -{ - struct tpacket_kbdq_core *pkc; - - pkc =3D GET_PBDQC_FROM_RB(&po->rx_ring); - timer_setup(&pkc->retire_blk_timer, prb_retire_rx_blk_timer_expired, - 0); - pkc->retire_blk_timer.expires =3D jiffies; + hrtimer_cancel(&pkc->retire_blk_timer); } =20 static int prb_calc_retire_blk_tmo(struct packet_sock *po, @@ -671,53 +650,40 @@ static void init_prb_bdqc(struct packet_sock *po, p1->version =3D po->tp_version; po->stats.stats3.tp_freeze_q_cnt =3D 0; if (req_u->req3.tp_retire_blk_tov) - p1->retire_blk_tov =3D req_u->req3.tp_retire_blk_tov; + p1->interval_ktime =3D ms_to_ktime(req_u->req3.tp_retire_blk_tov); else - p1->retire_blk_tov =3D prb_calc_retire_blk_tmo(po, - req_u->req3.tp_block_size); - p1->tov_in_jiffies =3D msecs_to_jiffies(p1->retire_blk_tov); + p1->interval_ktime =3D ms_to_ktime(prb_calc_retire_blk_tmo(po, + req_u->req3.tp_block_size)); p1->blk_sizeof_priv =3D req_u->req3.tp_sizeof_priv; rwlock_init(&p1->blk_fill_in_prog_lock); =20 p1->max_frame_len =3D p1->kblk_size - BLK_PLUS_PRIV(p1->blk_sizeof_priv); prb_init_ft_ops(p1, req_u); - prb_setup_retire_blk_timer(po); + hrtimer_setup(&p1->retire_blk_timer, prb_retire_rx_blk_timer_expired, + CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT); + hrtimer_start(&p1->retire_blk_timer, p1->interval_ktime, + HRTIMER_MODE_REL_SOFT); prb_open_block(p1, pbd); } =20 -/* Do NOT update the last_blk_num first. - * Assumes sk_buff_head lock is held. - */ -static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *pkc) -{ - mod_timer(&pkc->retire_blk_timer, - jiffies + pkc->tov_in_jiffies); -} - /* - * Timer logic: - * 1) We refresh the timer only when we open a block. - * By doing this we don't waste cycles refreshing the timer - * on packet-by-packet basis. - * * With a 1MB block-size, on a 1Gbps line, it will take * i) ~8 ms to fill a block + ii) memcpy etc. * In this cut we are not accounting for the memcpy time. * - * So, if the user sets the 'tmo' to 10ms then the timer - * will never fire while the block is still getting filled - * (which is what we want). However, the user could choose - * to close a block early and that's fine. - * - * But when the timer does fire, we check whether or not to refresh it. * Since the tmo granularity is in msecs, it is not too expensive * to refresh the timer, lets say every '8' msecs. * Either the user can set the 'tmo' or we can derive it based on * a) line-speed and b) block-size. * prb_calc_retire_blk_tmo() calculates the tmo. * + * The retire hrtimer expiration is unconditional and periodic. + * See comment in prb_open_block. + * + * If there are numerous packet sockets on the system, please set an + * appropriate timeout to avoid frequent enqueueing of hrtimers. */ -static void prb_retire_rx_blk_timer_expired(struct timer_list *t) +static enum hrtimer_restart prb_retire_rx_blk_timer_expired(struct hrtimer= *t) { struct packet_sock *po =3D timer_container_of(po, t, rx_ring.prb_bdqc.retire_blk_timer); @@ -730,9 +696,6 @@ static void prb_retire_rx_blk_timer_expired(struct time= r_list *t) frozen =3D prb_queue_frozen(pkc); pbd =3D GET_CURR_PBLOCK_DESC_FROM_CORE(pkc); =20 - if (unlikely(pkc->delete_blk_timer)) - goto out; - /* We only need to plug the race when the block is partially filled. * tpacket_rcv: * lock(); increment BLOCK_NUM_PKTS; unlock() @@ -749,26 +712,16 @@ static void prb_retire_rx_blk_timer_expired(struct ti= mer_list *t) } =20 if (!frozen) { - if (!BLOCK_NUM_PKTS(pbd)) { - /* An empty block. Just refresh the timer. */ - goto refresh_timer; + if (BLOCK_NUM_PKTS(pbd)) { + /* Not an empty block. Need retire the block. */ + prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO); + prb_dispatch_next_block(pkc, po); } - prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO); - if (!prb_dispatch_next_block(pkc, po)) - goto refresh_timer; - else - goto out; } else { /* Case 1. Queue was frozen because user-space was * lagging behind. */ - if (prb_curr_blk_in_use(pbd)) { - /* - * Ok, user-space is still behind. - * So just refresh the timer. - */ - goto refresh_timer; - } else { + if (!prb_curr_blk_in_use(pbd)) { /* Case 2. queue was frozen,user-space caught up, * now the link went idle && the timer fired. * We don't have a block to close.So we open this @@ -777,15 +730,12 @@ static void prb_retire_rx_blk_timer_expired(struct ti= mer_list *t) * Thawing/timer-refresh is a side effect. */ prb_open_block(pkc, pbd); - goto out; } } =20 -refresh_timer: - _prb_refresh_rx_retire_blk_timer(pkc); - -out: + hrtimer_forward_now(&pkc->retire_blk_timer, pkc->interval_ktime); spin_unlock(&po->sk.sk_receive_queue.lock); + return HRTIMER_RESTART; } =20 static void prb_flush_block(struct tpacket_kbdq_core *pkc1, @@ -879,11 +829,18 @@ static void prb_thaw_queue(struct tpacket_kbdq_core *= pkc) } =20 /* - * Side effect of opening a block: + * prb_open_block is called by tpacket_rcv or timer callback. * - * 1) prb_queue is thawed. - * 2) retire_blk_timer is refreshed. + * Reasons why NOT update hrtimer in prb_open_block: + * 1) It will increase complexity to distinguish the two caller scenario. + * 2) hrtimer_cancel and hrtimer_start need to be called if you want to up= date + * TMO of an already enqueued hrtimer, leading to complex shutdown logic. * + * One side effect of NOT update hrtimer when called by tpacket_rcv is that + * a newly opened block triggered by tpacket_rcv may be retired earlier th= an + * expected. On the other hand, if timeout is updated in prb_open_block, t= he + * frequent reception of network packets that leads to prb_open_block being + * called may cause hrtimer to be removed and enqueued repeatedly. */ static void prb_open_block(struct tpacket_kbdq_core *pkc1, struct tpacket_block_desc *pbd1) @@ -917,7 +874,6 @@ static void prb_open_block(struct tpacket_kbdq_core *pk= c1, pkc1->pkblk_end =3D pkc1->pkblk_start + pkc1->kblk_size; =20 prb_thaw_queue(pkc1); - _prb_refresh_rx_retire_blk_timer(pkc1); =20 smp_wmb(); } diff --git a/net/packet/diag.c b/net/packet/diag.c index 6ce1dcc28..c8f43e0c1 100644 --- a/net/packet/diag.c +++ b/net/packet/diag.c @@ -83,7 +83,7 @@ static int pdiag_put_ring(struct packet_ring_buffer *ring= , int ver, int nl_type, pdr.pdr_frame_nr =3D ring->frame_max + 1; =20 if (ver > TPACKET_V2) { - pdr.pdr_retire_tmo =3D ring->prb_bdqc.retire_blk_tov; + pdr.pdr_retire_tmo =3D ktime_to_ms(ring->prb_bdqc.interval_ktime); pdr.pdr_sizeof_priv =3D ring->prb_bdqc.blk_sizeof_priv; pdr.pdr_features =3D ring->prb_bdqc.feature_req_word; } else { diff --git a/net/packet/internal.h b/net/packet/internal.h index d367b9f93..b76e645cd 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -20,10 +20,11 @@ struct tpacket_kbdq_core { unsigned int feature_req_word; unsigned int hdrlen; unsigned char reset_pending_on_curr_blk; - unsigned char delete_blk_timer; unsigned short kactive_blk_num; unsigned short blk_sizeof_priv; =20 + unsigned short version; + char *pkblk_start; char *pkblk_end; int kblk_size; @@ -32,6 +33,7 @@ struct tpacket_kbdq_core { uint64_t knxt_seq_num; char *prev; char *nxt_offset; + struct sk_buff *skb; =20 rwlock_t blk_fill_in_prog_lock; @@ -39,12 +41,10 @@ struct tpacket_kbdq_core { /* Default is set to 8ms */ #define DEFAULT_PRB_RETIRE_TOV (8) =20 - unsigned short retire_blk_tov; - unsigned short version; - unsigned long tov_in_jiffies; + ktime_t interval_ktime; =20 /* timer to retire an outstanding block */ - struct timer_list retire_blk_timer; + struct hrtimer retire_blk_timer; }; =20 struct pgv { --=20 2.34.1