Author: imp Date: Thu Jan 25 21:38:30 2018 New Revision: 328415 URL: https://svnweb.freebsd.org/changeset/base/328415
Log: Track Ref / DeRef and Hold / Unhold that da is doing to track down leaks. We assume each source can be taken / dropped only once and don't recurse. These are only enabled via DA_TRACK_REFS or INVARIANTS. There appreas to be a reference leak under extreme load, and these should help us colaberatively work it out. It also documents better the reference / holding protocol better. Reviewed by: ken@, scottl@ Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D14040 Modified: head/sys/cam/scsi/scsi_da.c head/sys/conf/options Modified: head/sys/cam/scsi/scsi_da.c ============================================================================== --- head/sys/cam/scsi/scsi_da.c Thu Jan 25 21:38:09 2018 (r328414) +++ head/sys/cam/scsi/scsi_da.c Thu Jan 25 21:38:30 2018 (r328415) @@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #ifdef _KERNEL +#include "opt_da.h" #include <sys/systm.h> #include <sys/kernel.h> #include <sys/bio.h> @@ -51,6 +52,7 @@ __FBSDID("$FreeBSD$"); #include <sys/sbuf.h> #include <geom/geom.h> #include <geom/geom_disk.h> +#include <machine/atomic.h> #endif /* _KERNEL */ #ifndef _KERNEL @@ -291,6 +293,18 @@ struct disk_params { #define DA_WORK_TUR (1 << 16) +typedef enum { + DA_REF_OPEN = 1, + DA_REF_OPEN_HOLD, + DA_REF_CLOSE_HOLD, + DA_REF_PROBE_HOLD, + DA_REF_TUR, + DA_REF_GEOM, + DA_REF_SYSCTL, + DA_REF_REPROBE, + DA_REF_MAX /* KEEP LAST */ +} da_ref_token; + struct da_softc { struct cam_iosched_softc *cam_iosched; struct bio_queue_head delete_run_queue; @@ -335,6 +349,7 @@ struct da_softc { uint8_t unmap_buf[UNMAP_BUF_SIZE]; struct scsi_read_capacity_data_long rcaplong; struct callout mediapoll_c; + int ref_flags[DA_REF_MAX]; #ifdef CAM_IO_STATS struct sysctl_ctx_list sysctl_stats_ctx; struct sysctl_oid *sysctl_stats_tree; @@ -1469,6 +1484,143 @@ PERIPHDRIVER_DECLARE(da, dadriver); static MALLOC_DEFINE(M_SCSIDA, "scsi_da", "scsi_da buffers"); +/* + * This driver takes out references / holds in well defined pairs, never + * recursively. These macros / inline functions enforce those rules. They + * are only enabled with DA_TRACK_REFS or INVARIANTS. If DA_TRACK_REFS is + * defined to be 2 or larger, the tracking also includes debug printfs. + */ +#if defined(DA_TRACK_REFS) || defined(INVARIANTS) + +#ifndef DA_TRACK_REFS +#define DA_TRACK_REFS 1 +#endif + +#if DA_TRACK_REFS > 1 +#define CAM_PERIPH_PRINT(p, msg, args...) \ + printf("%s%d:" msg, (periph)->periph_name, (periph)->unit_number, ##args) + +static const char *da_ref_text[] = { + "bogus", + "open", + "open hold", + "close hold", + "reprobe hold", + "Test Unit Ready", + "Geom", + "sysctl", + "reprobe", + "max -- also bogus" +}; + +#else +#define CAM_PERIPH_PRINT(p, msg, args...) +#endif + +static inline void +token_sanity(da_ref_token token) +{ + if ((unsigned)token >= DA_REF_MAX) + panic("Bad token value passed in %d\n", token); +} + +static inline int +da_periph_hold(struct cam_periph *periph, int priority, da_ref_token token) +{ + int err = cam_periph_hold(periph, priority); + + token_sanity(token); + CAM_PERIPH_PRINT(periph, "Holding device %s (%d): %d\n", + da_ref_text[token], token, err); + if (err == 0) { + int cnt; + struct da_softc *softc = periph->softc; + + cnt = atomic_fetchadd_int(&softc->ref_flags[token], 1); + if (cnt != 0) + panic("Re-holding for reason %d, cnt = %d", token, cnt); + } + return (err); +} + +static inline void +da_periph_unhold(struct cam_periph *periph, da_ref_token token) +{ + int cnt; + struct da_softc *softc = periph->softc; + + token_sanity(token); + cam_periph_unhold(periph); + CAM_PERIPH_PRINT(periph, "Unholding device %s (%d)\n", + da_ref_text[token], token); + cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1); + if (cnt != 1) + panic("Unholding %d with cnt = %d", token, cnt); +} + +static inline int +da_periph_acquire(struct cam_periph *periph, da_ref_token token) +{ + int err = cam_periph_acquire(periph); + + token_sanity(token); + CAM_PERIPH_PRINT(periph, "acquiring device %s (%d): %d\n", + da_ref_text[token], token, err); + if (err == CAM_REQ_CMP) { + int cnt; + struct da_softc *softc = periph->softc; + + cnt = atomic_fetchadd_int(&softc->ref_flags[token], 1); + if (cnt != 0) + panic("Re-refing for reason %d, cnt = %d", token, cnt); + } + return (err); +} + +static inline void +da_periph_release(struct cam_periph *periph, da_ref_token token) +{ + int cnt; + struct da_softc *softc = periph->softc; + + token_sanity(token); + cam_periph_release(periph); + CAM_PERIPH_PRINT(periph, "releasing device %s (%d)\n", + da_ref_text[token], token); + cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1); + if (cnt != 1) + panic("Unholding %d with cnt = %d", token, cnt); +} + +static inline void +da_periph_release_locked(struct cam_periph *periph, da_ref_token token) +{ + int cnt; + struct da_softc *softc = periph->softc; + + token_sanity(token); + cam_periph_release_locked(periph); + CAM_PERIPH_PRINT(periph, "releasing device (locked) %s (%d)\n", + da_ref_text[token], token); + cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1); + if (cnt != 1) + panic("Unholding %d with cnt = %d", token, cnt); +} + +#define cam_periph_hold POISON +#define cam_periph_unhold POISON +#define cam_periph_acquire POISON +#define cam_periph_release POISON +#define cam_periph_release_locked POISON + +#else +#define da_periph_hold(periph, prio, token) cam_periph_hold((periph), (prio)) +#define da_periph_unhold(periph, token) cam_periph_unhold((periph)) +#define da_periph_acquire(periph, token) cam_periph_acquire((periph)) +#define da_periph_release(periph, token) cam_periph_release((periph)) +#define da_periph_release_locked(periph, token) cam_periph_release_locked((periph)) +#endif + static int daopen(struct disk *dp) { @@ -1477,14 +1629,14 @@ daopen(struct disk *dp) int error; periph = (struct cam_periph *)dp->d_drv1; - if (cam_periph_acquire(periph) != CAM_REQ_CMP) { + if (da_periph_acquire(periph, DA_REF_OPEN) != CAM_REQ_CMP) { return (ENXIO); } cam_periph_lock(periph); - if ((error = cam_periph_hold(periph, PRIBIO|PCATCH)) != 0) { + if ((error = da_periph_hold(periph, PRIBIO|PCATCH, DA_REF_OPEN_HOLD)) != 0) { cam_periph_unlock(periph); - cam_periph_release(periph); + da_periph_release(periph, DA_REF_OPEN); return (error); } @@ -1512,11 +1664,11 @@ daopen(struct disk *dp) softc->flags |= DA_FLAG_OPEN; } - cam_periph_unhold(periph); + da_periph_unhold(periph, DA_REF_OPEN_HOLD); cam_periph_unlock(periph); if (error != 0) - cam_periph_release(periph); + da_periph_release(periph, DA_REF_OPEN); return (error); } @@ -1534,7 +1686,7 @@ daclose(struct disk *dp) CAM_DEBUG(periph->path, CAM_DEBUG_TRACE | CAM_DEBUG_PERIPH, ("daclose\n")); - if (cam_periph_hold(periph, PRIBIO) == 0) { + if (da_periph_hold(periph, PRIBIO, DA_REF_CLOSE_HOLD) == 0) { /* Flush disk cache. */ if ((softc->flags & DA_FLAG_DIRTY) != 0 && @@ -1557,7 +1709,7 @@ daclose(struct disk *dp) (softc->quirks & DA_Q_NO_PREVENT) == 0) daprevent(periph, PR_ALLOW); - cam_periph_unhold(periph); + da_periph_unhold(periph, DA_REF_CLOSE_HOLD); } /* @@ -1572,7 +1724,7 @@ daclose(struct disk *dp) while (softc->refcount != 0) cam_periph_sleep(periph, &softc->refcount, PRIBIO, "daclose", 1); cam_periph_unlock(periph); - cam_periph_release(periph); + da_periph_release(periph, DA_REF_OPEN); return (0); } @@ -1750,7 +1902,7 @@ dadiskgonecb(struct disk *dp) struct cam_periph *periph; periph = (struct cam_periph *)dp->d_drv1; - cam_periph_release(periph); + da_periph_release(periph, DA_REF_GEOM); } static void @@ -1910,7 +2062,7 @@ daasync(void *callback_arg, u_int32_t code, case AC_SCSI_AEN: softc = (struct da_softc *)periph->softc; if (!cam_iosched_has_work_flags(softc->cam_iosched, DA_WORK_TUR)) { - if (cam_periph_acquire(periph) == CAM_REQ_CMP) { + if (da_periph_acquire(periph, DA_REF_TUR) == CAM_REQ_CMP) { cam_iosched_set_work_flags(softc->cam_iosched, DA_WORK_TUR); daschedule(periph); } @@ -1955,7 +2107,7 @@ dasysctlinit(void *context, int pending) * periph was held for us when this task was enqueued */ if (periph->flags & CAM_PERIPH_INVALID) { - cam_periph_release(periph); + da_periph_release(periph, DA_REF_SYSCTL); return; } @@ -1970,7 +2122,7 @@ dasysctlinit(void *context, int pending) CTLFLAG_RD, 0, tmpstr, "device_index"); if (softc->sysctl_tree == NULL) { printf("dasysctlinit: unable to allocate sysctl tree\n"); - cam_periph_release(periph); + da_periph_release(periph, DA_REF_SYSCTL); return; } @@ -2052,7 +2204,7 @@ dasysctlinit(void *context, int pending) xpt_action((union ccb *)&cts); cam_periph_unlock(periph); if (cts.ccb_h.status != CAM_REQ_CMP) { - cam_periph_release(periph); + da_periph_release(periph, DA_REF_SYSCTL); return; } if (cts.protocol == PROTO_SCSI && cts.transport == XPORT_FC) { @@ -2103,7 +2255,7 @@ dasysctlinit(void *context, int pending) cam_iosched_sysctl_init(softc->cam_iosched, &softc->sysctl_ctx, softc->sysctl_tree); - cam_periph_release(periph); + da_periph_release(periph, DA_REF_SYSCTL); } static int @@ -2269,9 +2421,9 @@ daprobedone(struct cam_periph *periph, union ccb *ccb) wakeup(&softc->disk->d_mediasize); if ((softc->flags & DA_FLAG_ANNOUNCED) == 0) { softc->flags |= DA_FLAG_ANNOUNCED; - cam_periph_unhold(periph); + da_periph_unhold(periph, DA_REF_PROBE_HOLD); } else - cam_periph_release_locked(periph); + da_periph_release_locked(periph, DA_REF_REPROBE); } static void @@ -2484,8 +2636,10 @@ daregister(struct cam_periph *periph, void *arg) * Take an exclusive refcount on the periph while dastart is called * to finish the probe. The reference will be dropped in dadone at * the end of probe. + * + * XXX if cam_periph_hold returns an error, we don't hold a refcount. */ - (void)cam_periph_hold(periph, PRIBIO); + (void)da_periph_hold(periph, PRIBIO, DA_REF_PROBE_HOLD); /* * Schedule a periodic event to occasionally send an @@ -2579,7 +2733,7 @@ daregister(struct cam_periph *periph, void *arg) * We'll release this reference once GEOM calls us back (via * dadiskgonecb()) telling us that our provider has been freed. */ - if (cam_periph_acquire(periph) != CAM_REQ_CMP) { + if (da_periph_acquire(periph, DA_REF_GEOM) != CAM_REQ_CMP) { xpt_print(periph->path, "%s: lost periph during " "registration!\n", __func__); cam_periph_lock(periph); @@ -2965,7 +3119,7 @@ more: if (cam_iosched_has_work_flags(softc->cam_iosched, DA_WORK_TUR)) { cam_iosched_clr_work_flags(softc->cam_iosched, DA_WORK_TUR); - cam_periph_release_locked(periph); + da_periph_release_locked(periph, DA_REF_TUR); } if ((bp->bio_flags & BIO_ORDERED) != 0 || @@ -4547,7 +4701,7 @@ dadone(struct cam_periph *periph, union ccb *done_ccb) * we have successfully attached. */ /* increase the refcount */ - if (cam_periph_acquire(periph) == CAM_REQ_CMP) { + if (da_periph_acquire(periph, DA_REF_SYSCTL) == CAM_REQ_CMP) { taskqueue_enqueue(taskqueue_thread, &softc->sysctl_task); @@ -5392,7 +5546,7 @@ dadone(struct cam_periph *periph, union ccb *done_ccb) /*getcount_only*/0); } xpt_release_ccb(done_ccb); - cam_periph_release_locked(periph); + da_periph_release_locked(periph, DA_REF_TUR); return; } default: @@ -5413,7 +5567,7 @@ dareprobe(struct cam_periph *periph) if (softc->state != DA_STATE_NORMAL) return; - status = cam_periph_acquire(periph); + status = da_periph_acquire(periph, DA_REF_REPROBE); KASSERT(status == CAM_REQ_CMP, ("dareprobe: cam_periph_acquire failed")); @@ -5513,7 +5667,7 @@ damediapoll(void *arg) if (!cam_iosched_has_work_flags(softc->cam_iosched, DA_WORK_TUR) && LIST_EMPTY(&softc->pending_ccbs)) { - if (cam_periph_acquire(periph) == CAM_REQ_CMP) { + if (da_periph_acquire(periph, DA_REF_TUR) == CAM_REQ_CMP) { cam_iosched_set_work_flags(softc->cam_iosched, DA_WORK_TUR); daschedule(periph); } Modified: head/sys/conf/options ============================================================================== --- head/sys/conf/options Thu Jan 25 21:38:09 2018 (r328414) +++ head/sys/conf/options Thu Jan 25 21:38:30 2018 (r328415) @@ -345,6 +345,9 @@ ATA_STATIC_ID opt_ada.h CHANGER_MIN_BUSY_SECONDS opt_cd.h CHANGER_MAX_BUSY_SECONDS opt_cd.h +# Options used only in cam/scsi/scsi_da.c +DA_TRACK_REFS opt_da.h + # Options used only in cam/scsi/scsi_sa.c. SA_IO_TIMEOUT opt_sa.h SA_SPACE_TIMEOUT opt_sa.h _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
