| Message ID | 20210627231439.138612-6-matthew.brost@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | CT changes required for GuC submission | expand |
On 28.06.2021 01:14, Matthew Brost wrote: > Implement a stall timer which fails H2G CTBs once a period of time > with no forward progress is reached to prevent deadlock. > > v2: > (Michal) > - Improve error message in ct_deadlock() > - Set broken when ct_deadlock() returns true > - Return -EPIPE on ct_deadlock() > > Signed-off-by: John Harrison <John.C.Harrison@Intel.com> > Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> > Signed-off-by: Matthew Brost <matthew.brost@intel.com> > --- > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 62 ++++++++++++++++++++--- > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 4 ++ > 2 files changed, 59 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > index 90ee95a240e8..8f553f7f9619 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > @@ -319,6 +319,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) > goto err_deregister; > > ct->enabled = true; > + ct->stall_time = KTIME_MAX; > > return 0; > > @@ -391,9 +392,6 @@ static int ct_write(struct intel_guc_ct *ct, > u32 *cmds = ctb->cmds; > unsigned int i; > > - if (unlikely(ctb->broken)) > - return -EPIPE; > - > if (unlikely(desc->status)) > goto corrupted; > > @@ -509,6 +507,25 @@ static int wait_for_ct_request_update(struct ct_request *req, u32 *status) > return err; > } > > +#define GUC_CTB_TIMEOUT_MS 1500 > +static inline bool ct_deadlocked(struct intel_guc_ct *ct) > +{ > + long timeout = GUC_CTB_TIMEOUT_MS; > + bool ret = ktime_ms_delta(ktime_get(), ct->stall_time) > timeout; > + > + if (unlikely(ret)) { > + struct guc_ct_buffer_desc *send = ct->ctbs.send.desc; > + struct guc_ct_buffer_desc *recv = ct->ctbs.send.desc; > + > + CT_ERROR(ct, "Communication stalled for %lld, desc status=%#x,%#x\n", nit: missing unit in "stalled for ... ms" ^^^^ > + ktime_ms_delta(ktime_get(), ct->stall_time), > + send->status, recv->status); > + ct->ctbs.send.broken = true; > + } > + > + return ret; > +} > + > static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) > { > struct guc_ct_buffer_desc *desc = ctb->desc; > @@ -520,6 +537,26 @@ static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) > return space >= len_dw; > } > > +static int has_room_nb(struct intel_guc_ct *ct, u32 len_dw) > +{ > + struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; > + > + lockdep_assert_held(&ct->ctbs.send.lock); > + > + if (unlikely(!h2g_has_room(ctb, len_dw))) { > + if (ct->stall_time == KTIME_MAX) > + ct->stall_time = ktime_get(); > + > + if (unlikely(ct_deadlocked(ct))) > + return -EPIPE; > + else > + return -EBUSY; > + } > + > + ct->stall_time = KTIME_MAX; > + return 0; > +} > + > static int ct_send_nb(struct intel_guc_ct *ct, > const u32 *action, > u32 len, > @@ -530,13 +567,14 @@ static int ct_send_nb(struct intel_guc_ct *ct, > u32 fence; > int ret; > > + if (unlikely(ctb->broken)) > + return -EPIPE; > + > spin_lock_irqsave(&ctb->lock, spin_flags); > > - ret = h2g_has_room(ctb, len + GUC_CTB_HDR_LEN); > - if (unlikely(!ret)) { > - ret = -EBUSY; > + ret = has_room_nb(ct, len + GUC_CTB_HDR_LEN); > + if (unlikely(ret)) > goto out; > - } > > fence = ct_get_next_fence(ct); > ret = ct_write(ct, action, len, fence, flags); > @@ -571,6 +609,9 @@ static int ct_send(struct intel_guc_ct *ct, > GEM_BUG_ON(!response_buf && response_buf_size); > might_sleep(); > > + if (unlikely(ctb->broken)) > + return -EPIPE; ok, but likely could be part of ct_can_send/has_room > + > /* > * We use a lazy spin wait loop here as we believe that if the CT > * buffers are sized correctly the flow control condition should be > @@ -579,8 +620,13 @@ static int ct_send(struct intel_guc_ct *ct, > retry: > spin_lock_irqsave(&ctb->lock, flags); > if (unlikely(!h2g_has_room(ctb, len + GUC_CTB_HDR_LEN))) { > + if (ct->stall_time == KTIME_MAX) > + ct->stall_time = ktime_get(); > spin_unlock_irqrestore(&ctb->lock, flags); > > + if (unlikely(ct_deadlocked(ct))) > + return -EPIPE; > + can't we really put all this into one place? static int ct_can_send(struct intel_guc_ct *ct, u32 len_dw, bool wait) { struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; lockdep_assert_held(&ct->ctbs.send.lock); retry: if (ct->broken) return -EPIPE; if (unlikely(!ctb_has_room(ctb, len_dw + GUC_CTB_HDR_LEN))) { if (ct->stall_time == KTIME_MAX) ct->stall_time = ktime_get(); if (unlikely(ct_deadlocked(ct))) return -EPIPE; if (!wait) return -EBUSY; spin_unlock_irqrestore(&ctb->lock, flags); ... spin_lock_irqrestore(&ctb->lock, flags); goto retry; } ct->stall_time = KTIME_MAX; return 0; } Michal > if (msleep_interruptible(sleep_period_ms)) > return -EINTR; > sleep_period_ms = sleep_period_ms << 1; > @@ -588,6 +634,8 @@ static int ct_send(struct intel_guc_ct *ct, > goto retry; > } > > + ct->stall_time = KTIME_MAX; > + > fence = ct_get_next_fence(ct); > request.fence = fence; > request.status = 0; > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > index f6a4d5b33467..c9d6ae7848a7 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > @@ -9,6 +9,7 @@ > #include <linux/interrupt.h> > #include <linux/spinlock.h> > #include <linux/workqueue.h> > +#include <linux/ktime.h> > > #include "intel_guc_fwif.h" > > @@ -68,6 +69,9 @@ struct intel_guc_ct { > struct list_head incoming; /* incoming requests */ > struct work_struct worker; /* handler for incoming requests */ > } requests; > + > + /** @stall_time: time of first time a CTB submission is stalled */ > + ktime_t stall_time; > }; > > void intel_guc_ct_init_early(struct intel_guc_ct *ct); >
On Thu, Jul 01, 2021 at 01:23:36AM +0200, Michal Wajdeczko wrote: > > > On 28.06.2021 01:14, Matthew Brost wrote: > > Implement a stall timer which fails H2G CTBs once a period of time > > with no forward progress is reached to prevent deadlock. > > > > v2: > > (Michal) > > - Improve error message in ct_deadlock() > > - Set broken when ct_deadlock() returns true > > - Return -EPIPE on ct_deadlock() > > > > Signed-off-by: John Harrison <John.C.Harrison@Intel.com> > > Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> > > Signed-off-by: Matthew Brost <matthew.brost@intel.com> > > --- > > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 62 ++++++++++++++++++++--- > > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 4 ++ > > 2 files changed, 59 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > > index 90ee95a240e8..8f553f7f9619 100644 > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c > > @@ -319,6 +319,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) > > goto err_deregister; > > > > ct->enabled = true; > > + ct->stall_time = KTIME_MAX; > > > > return 0; > > > > @@ -391,9 +392,6 @@ static int ct_write(struct intel_guc_ct *ct, > > u32 *cmds = ctb->cmds; > > unsigned int i; > > > > - if (unlikely(ctb->broken)) > > - return -EPIPE; > > - > > if (unlikely(desc->status)) > > goto corrupted; > > > > @@ -509,6 +507,25 @@ static int wait_for_ct_request_update(struct ct_request *req, u32 *status) > > return err; > > } > > > > +#define GUC_CTB_TIMEOUT_MS 1500 > > +static inline bool ct_deadlocked(struct intel_guc_ct *ct) > > +{ > > + long timeout = GUC_CTB_TIMEOUT_MS; > > + bool ret = ktime_ms_delta(ktime_get(), ct->stall_time) > timeout; > > + > > + if (unlikely(ret)) { > > + struct guc_ct_buffer_desc *send = ct->ctbs.send.desc; > > + struct guc_ct_buffer_desc *recv = ct->ctbs.send.desc; > > + > > + CT_ERROR(ct, "Communication stalled for %lld, desc status=%#x,%#x\n", > > nit: missing unit in "stalled for ... ms" > ^^^^ Yep, will fix. > > > + ktime_ms_delta(ktime_get(), ct->stall_time), > > + send->status, recv->status); > > + ct->ctbs.send.broken = true; > > + } > > + > > + return ret; > > +} > > + > > static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) > > { > > struct guc_ct_buffer_desc *desc = ctb->desc; > > @@ -520,6 +537,26 @@ static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) > > return space >= len_dw; > > } > > > > +static int has_room_nb(struct intel_guc_ct *ct, u32 len_dw) > > +{ > > + struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; > > + > > + lockdep_assert_held(&ct->ctbs.send.lock); > > + > > + if (unlikely(!h2g_has_room(ctb, len_dw))) { > > + if (ct->stall_time == KTIME_MAX) > > + ct->stall_time = ktime_get(); > > + > > + if (unlikely(ct_deadlocked(ct))) > > + return -EPIPE; > > + else > > + return -EBUSY; > > + } > > + > > + ct->stall_time = KTIME_MAX; > > + return 0; > > +} > > + > > static int ct_send_nb(struct intel_guc_ct *ct, > > const u32 *action, > > u32 len, > > @@ -530,13 +567,14 @@ static int ct_send_nb(struct intel_guc_ct *ct, > > u32 fence; > > int ret; > > > > + if (unlikely(ctb->broken)) > > + return -EPIPE; > > + > > spin_lock_irqsave(&ctb->lock, spin_flags); > > > > - ret = h2g_has_room(ctb, len + GUC_CTB_HDR_LEN); > > - if (unlikely(!ret)) { > > - ret = -EBUSY; > > + ret = has_room_nb(ct, len + GUC_CTB_HDR_LEN); > > + if (unlikely(ret)) > > goto out; > > - } > > > > fence = ct_get_next_fence(ct); > > ret = ct_write(ct, action, len, fence, flags); > > @@ -571,6 +609,9 @@ static int ct_send(struct intel_guc_ct *ct, > > GEM_BUG_ON(!response_buf && response_buf_size); > > might_sleep(); > > > > + if (unlikely(ctb->broken)) > > + return -EPIPE; > > ok, but likely could be part of ct_can_send/has_room > No, this actually should be apart of 'intel_guc_ct_send'. > > + > > /* > > * We use a lazy spin wait loop here as we believe that if the CT > > * buffers are sized correctly the flow control condition should be > > @@ -579,8 +620,13 @@ static int ct_send(struct intel_guc_ct *ct, > > retry: > > spin_lock_irqsave(&ctb->lock, flags); > > if (unlikely(!h2g_has_room(ctb, len + GUC_CTB_HDR_LEN))) { > > + if (ct->stall_time == KTIME_MAX) > > + ct->stall_time = ktime_get(); > > spin_unlock_irqrestore(&ctb->lock, flags); > > > > + if (unlikely(ct_deadlocked(ct))) > > + return -EPIPE; > > + > > can't we really put all this into one place? > Maybe? IMO a helper with arguments might be worse that inline code depending on how it looks in the end. Now that you mention this I realize the patch that handles G2H credits is wrong as we really need to reserve credits here too. When I rework that patch, I'll revisit this. Matt > static int ct_can_send(struct intel_guc_ct *ct, u32 len_dw, bool wait) > { > struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; > > lockdep_assert_held(&ct->ctbs.send.lock); > > retry: > if (ct->broken) > return -EPIPE; > > if (unlikely(!ctb_has_room(ctb, len_dw + GUC_CTB_HDR_LEN))) { > if (ct->stall_time == KTIME_MAX) > ct->stall_time = ktime_get(); > > if (unlikely(ct_deadlocked(ct))) > return -EPIPE; > if (!wait) > return -EBUSY; > > spin_unlock_irqrestore(&ctb->lock, flags); > ... > spin_lock_irqrestore(&ctb->lock, flags); > > goto retry; > } > > ct->stall_time = KTIME_MAX; > return 0; > } > > Michal > > > if (msleep_interruptible(sleep_period_ms)) > > return -EINTR; > > sleep_period_ms = sleep_period_ms << 1; > > @@ -588,6 +634,8 @@ static int ct_send(struct intel_guc_ct *ct, > > goto retry; > > } > > > > + ct->stall_time = KTIME_MAX; > > + > > fence = ct_get_next_fence(ct); > > request.fence = fence; > > request.status = 0; > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > > index f6a4d5b33467..c9d6ae7848a7 100644 > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h > > @@ -9,6 +9,7 @@ > > #include <linux/interrupt.h> > > #include <linux/spinlock.h> > > #include <linux/workqueue.h> > > +#include <linux/ktime.h> > > > > #include "intel_guc_fwif.h" > > > > @@ -68,6 +69,9 @@ struct intel_guc_ct { > > struct list_head incoming; /* incoming requests */ > > struct work_struct worker; /* handler for incoming requests */ > > } requests; > > + > > + /** @stall_time: time of first time a CTB submission is stalled */ > > + ktime_t stall_time; > > }; > > > > void intel_guc_ct_init_early(struct intel_guc_ct *ct); > >
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c index 90ee95a240e8..8f553f7f9619 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c @@ -319,6 +319,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) goto err_deregister; ct->enabled = true; + ct->stall_time = KTIME_MAX; return 0; @@ -391,9 +392,6 @@ static int ct_write(struct intel_guc_ct *ct, u32 *cmds = ctb->cmds; unsigned int i; - if (unlikely(ctb->broken)) - return -EPIPE; - if (unlikely(desc->status)) goto corrupted; @@ -509,6 +507,25 @@ static int wait_for_ct_request_update(struct ct_request *req, u32 *status) return err; } +#define GUC_CTB_TIMEOUT_MS 1500 +static inline bool ct_deadlocked(struct intel_guc_ct *ct) +{ + long timeout = GUC_CTB_TIMEOUT_MS; + bool ret = ktime_ms_delta(ktime_get(), ct->stall_time) > timeout; + + if (unlikely(ret)) { + struct guc_ct_buffer_desc *send = ct->ctbs.send.desc; + struct guc_ct_buffer_desc *recv = ct->ctbs.send.desc; + + CT_ERROR(ct, "Communication stalled for %lld, desc status=%#x,%#x\n", + ktime_ms_delta(ktime_get(), ct->stall_time), + send->status, recv->status); + ct->ctbs.send.broken = true; + } + + return ret; +} + static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) { struct guc_ct_buffer_desc *desc = ctb->desc; @@ -520,6 +537,26 @@ static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) return space >= len_dw; } +static int has_room_nb(struct intel_guc_ct *ct, u32 len_dw) +{ + struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; + + lockdep_assert_held(&ct->ctbs.send.lock); + + if (unlikely(!h2g_has_room(ctb, len_dw))) { + if (ct->stall_time == KTIME_MAX) + ct->stall_time = ktime_get(); + + if (unlikely(ct_deadlocked(ct))) + return -EPIPE; + else + return -EBUSY; + } + + ct->stall_time = KTIME_MAX; + return 0; +} + static int ct_send_nb(struct intel_guc_ct *ct, const u32 *action, u32 len, @@ -530,13 +567,14 @@ static int ct_send_nb(struct intel_guc_ct *ct, u32 fence; int ret; + if (unlikely(ctb->broken)) + return -EPIPE; + spin_lock_irqsave(&ctb->lock, spin_flags); - ret = h2g_has_room(ctb, len + GUC_CTB_HDR_LEN); - if (unlikely(!ret)) { - ret = -EBUSY; + ret = has_room_nb(ct, len + GUC_CTB_HDR_LEN); + if (unlikely(ret)) goto out; - } fence = ct_get_next_fence(ct); ret = ct_write(ct, action, len, fence, flags); @@ -571,6 +609,9 @@ static int ct_send(struct intel_guc_ct *ct, GEM_BUG_ON(!response_buf && response_buf_size); might_sleep(); + if (unlikely(ctb->broken)) + return -EPIPE; + /* * We use a lazy spin wait loop here as we believe that if the CT * buffers are sized correctly the flow control condition should be @@ -579,8 +620,13 @@ static int ct_send(struct intel_guc_ct *ct, retry: spin_lock_irqsave(&ctb->lock, flags); if (unlikely(!h2g_has_room(ctb, len + GUC_CTB_HDR_LEN))) { + if (ct->stall_time == KTIME_MAX) + ct->stall_time = ktime_get(); spin_unlock_irqrestore(&ctb->lock, flags); + if (unlikely(ct_deadlocked(ct))) + return -EPIPE; + if (msleep_interruptible(sleep_period_ms)) return -EINTR; sleep_period_ms = sleep_period_ms << 1; @@ -588,6 +634,8 @@ static int ct_send(struct intel_guc_ct *ct, goto retry; } + ct->stall_time = KTIME_MAX; + fence = ct_get_next_fence(ct); request.fence = fence; request.status = 0; diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h index f6a4d5b33467..c9d6ae7848a7 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h @@ -9,6 +9,7 @@ #include <linux/interrupt.h> #include <linux/spinlock.h> #include <linux/workqueue.h> +#include <linux/ktime.h> #include "intel_guc_fwif.h" @@ -68,6 +69,9 @@ struct intel_guc_ct { struct list_head incoming; /* incoming requests */ struct work_struct worker; /* handler for incoming requests */ } requests; + + /** @stall_time: time of first time a CTB submission is stalled */ + ktime_t stall_time; }; void intel_guc_ct_init_early(struct intel_guc_ct *ct);