From f32c9e03d4a8dfe4880c830a353de7cfb49a3755 Mon Sep 17 00:00:00 2001 From: Martin Peschke Date: Fri, 28 Jul 2017 12:31:08 +0200 Subject: [PATCH] scsi: zfcp: early returns for traces disabled via level This patch adds early checks to avoid burning CPU cycles on the assembly of trace entries which would be skipped anyway. Introduce a static const variable to keep the trace level to check with debug_level_enabled() in sync with the actual trace emit with debug_event(). In order not to refactor the SAN tracing too much, simply use a define instead. This change is only for the non / semi hot paths, while the actual (I/O) hot path was already improved earlier: zfcp_dbf_scsi() is already guarded by its only caller _zfcp_dbf_scsi() since commit dcd20e2316cd ("[SCSI] zfcp: Only collect SCSI debug data for matching trace levels"). zfcp_dbf_hba_fsf_res() is already guarded by its only caller zfcp_dbf_hba_fsf_response() since commit 2e261af84cdb ("[SCSI] zfcp: Only collect FSF/HBA debug data for matching trace levels"). Signed-off-by: Martin Peschke [maier@linux.vnet.ibm.com: rebase, reword, default level 3 branch prediction] Signed-off-by: Steffen Maier Reviewed-by: Benjamin Block Signed-off-by: Benjamin Block Signed-off-by: Martin K. Petersen --- drivers/s390/scsi/zfcp_dbf.c | 54 ++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 8 deletions(-) diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c index 484da0b2d678..8227076c9cbb 100644 --- a/drivers/s390/scsi/zfcp_dbf.c +++ b/drivers/s390/scsi/zfcp_dbf.c @@ -113,8 +113,12 @@ void zfcp_dbf_hba_fsf_uss(char *tag, struct zfcp_fsf_req *req) struct zfcp_dbf *dbf = req->adapter->dbf; struct fsf_status_read_buffer *srb = req->data; struct zfcp_dbf_hba *rec = &dbf->hba_buf; + static int const level = 2; unsigned long flags; + if (unlikely(!debug_level_enabled(dbf->hba, level))) + return; + spin_lock_irqsave(&dbf->hba_lock, flags); memset(rec, 0, sizeof(*rec)); @@ -142,7 +146,7 @@ void zfcp_dbf_hba_fsf_uss(char *tag, struct zfcp_fsf_req *req) zfcp_dbf_pl_write(dbf, srb->payload.data, rec->pl_len, "fsf_uss", req->req_id); log: - debug_event(dbf->hba, 2, rec, sizeof(*rec)); + debug_event(dbf->hba, level, rec, sizeof(*rec)); spin_unlock_irqrestore(&dbf->hba_lock, flags); } @@ -156,8 +160,12 @@ void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req) struct zfcp_dbf *dbf = req->adapter->dbf; struct zfcp_dbf_hba *rec = &dbf->hba_buf; struct fsf_status_read_buffer *sr_buf = req->data; + static int const level = 1; unsigned long flags; + if (unlikely(!debug_level_enabled(dbf->hba, level))) + return; + spin_lock_irqsave(&dbf->hba_lock, flags); memset(rec, 0, sizeof(*rec)); @@ -169,7 +177,7 @@ void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req) memcpy(&rec->u.be, &sr_buf->payload.bit_error, sizeof(struct fsf_bit_error_payload)); - debug_event(dbf->hba, 1, rec, sizeof(*rec)); + debug_event(dbf->hba, level, rec, sizeof(*rec)); spin_unlock_irqrestore(&dbf->hba_lock, flags); } @@ -186,8 +194,12 @@ void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount, struct zfcp_dbf *dbf = adapter->dbf; struct zfcp_dbf_pay *payload = &dbf->pay_buf; unsigned long flags; + static int const level = 1; u16 length; + if (unlikely(!debug_level_enabled(dbf->pay, level))) + return; + if (!pl) return; @@ -202,7 +214,7 @@ void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount, while (payload->counter < scount && (char *)pl[payload->counter]) { memcpy(payload->data, (char *)pl[payload->counter], length); - debug_event(dbf->pay, 1, payload, zfcp_dbf_plen(length)); + debug_event(dbf->pay, level, payload, zfcp_dbf_plen(length)); payload->counter++; } @@ -217,15 +229,19 @@ void zfcp_dbf_hba_basic(char *tag, struct zfcp_adapter *adapter) { struct zfcp_dbf *dbf = adapter->dbf; struct zfcp_dbf_hba *rec = &dbf->hba_buf; + static int const level = 1; unsigned long flags; + if (unlikely(!debug_level_enabled(dbf->hba, level))) + return; + spin_lock_irqsave(&dbf->hba_lock, flags); memset(rec, 0, sizeof(*rec)); memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN); rec->id = ZFCP_DBF_HBA_BASIC; - debug_event(dbf->hba, 1, rec, sizeof(*rec)); + debug_event(dbf->hba, level, rec, sizeof(*rec)); spin_unlock_irqrestore(&dbf->hba_lock, flags); } @@ -264,9 +280,13 @@ void zfcp_dbf_rec_trig(char *tag, struct zfcp_adapter *adapter, { struct zfcp_dbf *dbf = adapter->dbf; struct zfcp_dbf_rec *rec = &dbf->rec_buf; + static int const level = 1; struct list_head *entry; unsigned long flags; + if (unlikely(!debug_level_enabled(dbf->rec, level))) + return; + spin_lock_irqsave(&dbf->rec_lock, flags); memset(rec, 0, sizeof(*rec)); @@ -283,7 +303,7 @@ void zfcp_dbf_rec_trig(char *tag, struct zfcp_adapter *adapter, rec->u.trig.want = want; rec->u.trig.need = need; - debug_event(dbf->rec, 1, rec, sizeof(*rec)); + debug_event(dbf->rec, level, rec, sizeof(*rec)); spin_unlock_irqrestore(&dbf->rec_lock, flags); } @@ -300,6 +320,9 @@ void zfcp_dbf_rec_run_lvl(int level, char *tag, struct zfcp_erp_action *erp) struct zfcp_dbf_rec *rec = &dbf->rec_buf; unsigned long flags; + if (!debug_level_enabled(dbf->rec, level)) + return; + spin_lock_irqsave(&dbf->rec_lock, flags); memset(rec, 0, sizeof(*rec)); @@ -345,8 +368,12 @@ void zfcp_dbf_rec_run_wka(char *tag, struct zfcp_fc_wka_port *wka_port, { struct zfcp_dbf *dbf = wka_port->adapter->dbf; struct zfcp_dbf_rec *rec = &dbf->rec_buf; + static int const level = 1; unsigned long flags; + if (unlikely(!debug_level_enabled(dbf->rec, level))) + return; + spin_lock_irqsave(&dbf->rec_lock, flags); memset(rec, 0, sizeof(*rec)); @@ -362,10 +389,12 @@ void zfcp_dbf_rec_run_wka(char *tag, struct zfcp_fc_wka_port *wka_port, rec->u.run.rec_action = ~0; rec->u.run.rec_count = ~0; - debug_event(dbf->rec, 1, rec, sizeof(*rec)); + debug_event(dbf->rec, level, rec, sizeof(*rec)); spin_unlock_irqrestore(&dbf->rec_lock, flags); } +#define ZFCP_DBF_SAN_LEVEL 1 + static inline void zfcp_dbf_san(char *tag, struct zfcp_dbf *dbf, char *paytag, struct scatterlist *sg, u8 id, u16 len, @@ -408,7 +437,7 @@ void zfcp_dbf_san(char *tag, struct zfcp_dbf *dbf, (u16)(sg->length - offset)); /* cap_len <= pay_sum < cap_len+ZFCP_DBF_PAY_MAX_REC */ memcpy(payload->data, sg_virt(sg) + offset, pay_len); - debug_event(dbf->pay, 1, payload, + debug_event(dbf->pay, ZFCP_DBF_SAN_LEVEL, payload, zfcp_dbf_plen(pay_len)); payload->counter++; offset += pay_len; @@ -418,7 +447,7 @@ void zfcp_dbf_san(char *tag, struct zfcp_dbf *dbf, spin_unlock(&dbf->pay_lock); out: - debug_event(dbf->san, 1, rec, sizeof(*rec)); + debug_event(dbf->san, ZFCP_DBF_SAN_LEVEL, rec, sizeof(*rec)); spin_unlock_irqrestore(&dbf->san_lock, flags); } @@ -434,6 +463,9 @@ void zfcp_dbf_san_req(char *tag, struct zfcp_fsf_req *fsf, u32 d_id) struct zfcp_fsf_ct_els *ct_els = fsf->data; u16 length; + if (unlikely(!debug_level_enabled(dbf->san, ZFCP_DBF_SAN_LEVEL))) + return; + length = (u16)zfcp_qdio_real_bytes(ct_els->req); zfcp_dbf_san(tag, dbf, "san_req", ct_els->req, ZFCP_DBF_SAN_REQ, length, fsf->req_id, d_id, length); @@ -512,6 +544,9 @@ void zfcp_dbf_san_res(char *tag, struct zfcp_fsf_req *fsf) struct zfcp_fsf_ct_els *ct_els = fsf->data; u16 length; + if (unlikely(!debug_level_enabled(dbf->san, ZFCP_DBF_SAN_LEVEL))) + return; + length = (u16)zfcp_qdio_real_bytes(ct_els->resp); zfcp_dbf_san(tag, dbf, "san_res", ct_els->resp, ZFCP_DBF_SAN_RES, length, fsf->req_id, ct_els->d_id, @@ -531,6 +566,9 @@ void zfcp_dbf_san_in_els(char *tag, struct zfcp_fsf_req *fsf) u16 length; struct scatterlist sg; + if (unlikely(!debug_level_enabled(dbf->san, ZFCP_DBF_SAN_LEVEL))) + return; + length = (u16)(srb->length - offsetof(struct fsf_status_read_buffer, payload)); sg_init_one(&sg, srb->payload.data, length); -- 2.45.2