From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- net/nfc/digital.h | 171 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 171 insertions(+) create mode 100644 net/nfc/digital.h (limited to 'net/nfc/digital.h') diff --git a/net/nfc/digital.h b/net/nfc/digital.h new file mode 100644 index 000000000..c33b2f7e1 --- /dev/null +++ b/net/nfc/digital.h @@ -0,0 +1,171 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * NFC Digital Protocol stack + * Copyright (c) 2013, Intel Corporation. + */ + +#ifndef __DIGITAL_H +#define __DIGITAL_H + +#include +#include + +#include +#include + +#define PROTOCOL_ERR(req) pr_err("%d: NFC Digital Protocol error: %s\n", \ + __LINE__, req) + +#define DIGITAL_CMD_IN_SEND 0 +#define DIGITAL_CMD_TG_SEND 1 +#define DIGITAL_CMD_TG_LISTEN 2 +#define DIGITAL_CMD_TG_LISTEN_MDAA 3 +#define DIGITAL_CMD_TG_LISTEN_MD 4 + +#define DIGITAL_MAX_HEADER_LEN 7 +#define DIGITAL_CRC_LEN 2 + +#define DIGITAL_SENSF_NFCID2_NFC_DEP_B1 0x01 +#define DIGITAL_SENSF_NFCID2_NFC_DEP_B2 0xFE + +#define DIGITAL_SENS_RES_NFC_DEP 0x0100 +#define DIGITAL_SEL_RES_NFC_DEP 0x40 +#define DIGITAL_SENSF_FELICA_SC 0xFFFF + +#define DIGITAL_DRV_CAPS_IN_CRC(ddev) \ + ((ddev)->driver_capabilities & NFC_DIGITAL_DRV_CAPS_IN_CRC) +#define DIGITAL_DRV_CAPS_TG_CRC(ddev) \ + ((ddev)->driver_capabilities & NFC_DIGITAL_DRV_CAPS_TG_CRC) + +struct digital_data_exch { + data_exchange_cb_t cb; + void *cb_context; +}; + +struct sk_buff *digital_skb_alloc(struct nfc_digital_dev *ddev, + unsigned int len); + +int digital_send_cmd(struct nfc_digital_dev *ddev, u8 cmd_type, + struct sk_buff *skb, struct digital_tg_mdaa_params *params, + u16 timeout, nfc_digital_cmd_complete_t cmd_cb, + void *cb_context); + +int digital_in_configure_hw(struct nfc_digital_dev *ddev, int type, int param); +static inline int digital_in_send_cmd(struct nfc_digital_dev *ddev, + struct sk_buff *skb, u16 timeout, + nfc_digital_cmd_complete_t cmd_cb, + void *cb_context) +{ + return digital_send_cmd(ddev, DIGITAL_CMD_IN_SEND, skb, NULL, timeout, + cmd_cb, cb_context); +} + +void digital_poll_next_tech(struct nfc_digital_dev *ddev); + +int digital_in_send_sens_req(struct nfc_digital_dev *ddev, u8 rf_tech); +int digital_in_send_sensb_req(struct nfc_digital_dev *ddev, u8 rf_tech); +int digital_in_send_sensf_req(struct nfc_digital_dev *ddev, u8 rf_tech); +int digital_in_send_iso15693_inv_req(struct nfc_digital_dev *ddev, u8 rf_tech); + +int digital_in_iso_dep_pull_sod(struct nfc_digital_dev *ddev, + struct sk_buff *skb); +int digital_in_iso_dep_push_sod(struct nfc_digital_dev *ddev, + struct sk_buff *skb); + +int digital_target_found(struct nfc_digital_dev *ddev, + struct nfc_target *target, u8 protocol); + +int digital_in_recv_mifare_res(struct sk_buff *resp); + +int digital_in_send_atr_req(struct nfc_digital_dev *ddev, + struct nfc_target *target, __u8 comm_mode, __u8 *gb, + size_t gb_len); +int digital_in_send_dep_req(struct nfc_digital_dev *ddev, + struct nfc_target *target, struct sk_buff *skb, + struct digital_data_exch *data_exch); + +int digital_tg_configure_hw(struct nfc_digital_dev *ddev, int type, int param); +static inline int digital_tg_send_cmd(struct nfc_digital_dev *ddev, + struct sk_buff *skb, u16 timeout, + nfc_digital_cmd_complete_t cmd_cb, void *cb_context) +{ + return digital_send_cmd(ddev, DIGITAL_CMD_TG_SEND, skb, NULL, timeout, + cmd_cb, cb_context); +} + +void digital_tg_recv_sens_req(struct nfc_digital_dev *ddev, void *arg, + struct sk_buff *resp); + +void digital_tg_recv_sensf_req(struct nfc_digital_dev *ddev, void *arg, + struct sk_buff *resp); + +static inline int digital_tg_listen(struct nfc_digital_dev *ddev, u16 timeout, + nfc_digital_cmd_complete_t cb, void *arg) +{ + return digital_send_cmd(ddev, DIGITAL_CMD_TG_LISTEN, NULL, NULL, + timeout, cb, arg); +} + +void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg, + struct sk_buff *resp); + +int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb); + +int digital_tg_listen_nfca(struct nfc_digital_dev *ddev, u8 rf_tech); +int digital_tg_listen_nfcf(struct nfc_digital_dev *ddev, u8 rf_tech); +void digital_tg_recv_md_req(struct nfc_digital_dev *ddev, void *arg, + struct sk_buff *resp); + +typedef u16 (*crc_func_t)(u16, const u8 *, size_t); + +#define CRC_A_INIT 0x6363 +#define CRC_B_INIT 0xFFFF +#define CRC_F_INIT 0x0000 + +void digital_skb_add_crc(struct sk_buff *skb, crc_func_t crc_func, u16 init, + u8 bitwise_inv, u8 msb_first); + +static inline void digital_skb_add_crc_a(struct sk_buff *skb) +{ + digital_skb_add_crc(skb, crc_ccitt, CRC_A_INIT, 0, 0); +} + +static inline void digital_skb_add_crc_b(struct sk_buff *skb) +{ + digital_skb_add_crc(skb, crc_ccitt, CRC_B_INIT, 1, 0); +} + +static inline void digital_skb_add_crc_f(struct sk_buff *skb) +{ + digital_skb_add_crc(skb, crc_itu_t, CRC_F_INIT, 0, 1); +} + +static inline void digital_skb_add_crc_none(struct sk_buff *skb) +{ + return; +} + +int digital_skb_check_crc(struct sk_buff *skb, crc_func_t crc_func, + u16 crc_init, u8 bitwise_inv, u8 msb_first); + +static inline int digital_skb_check_crc_a(struct sk_buff *skb) +{ + return digital_skb_check_crc(skb, crc_ccitt, CRC_A_INIT, 0, 0); +} + +static inline int digital_skb_check_crc_b(struct sk_buff *skb) +{ + return digital_skb_check_crc(skb, crc_ccitt, CRC_B_INIT, 1, 0); +} + +static inline int digital_skb_check_crc_f(struct sk_buff *skb) +{ + return digital_skb_check_crc(skb, crc_itu_t, CRC_F_INIT, 0, 1); +} + +static inline int digital_skb_check_crc_none(struct sk_buff *skb) +{ + return 0; +} + +#endif /* __DIGITAL_H */ -- cgit v1.3.1