summaryrefslogtreecommitdiffstats
path: root/kernel/gsp_sema_service.c
Commit message (Collapse)AuthorAge
* vgsp-sema r577: never let a foreign release VA claim a CE channel's tracking ↵Arthur Hanson Rasmusson15 hours
| | | | | | | | | | | | | | | | | | | | | | | | slot; event-record A/B knobs; GR-DEC dump deepened r575 starved-release wedge (live): an unreadable UVM CE entry's rescued stale page decoded a release to a foreign VA (0x12006c004, pay=60); the rescue paths adopted it as the channel's tracking slot (last_rel_va) and every later recovery release targeted it, while the client's real pool (0x121000000) stopped at 25 - the client spun in uvm_tracker_wait for 34 (exact-slot poke delivered it and the client completed green). For CE channels only a pool-shaped release target (0x121000000..0x122000000) may become last_rel_va; a foreign rescued release is refused (witnessed, bounded) and the pool step is delivered through the exact-slot fallback / deferred-release machinery instead. The fake's read-before-write keeps the delivery monotonic even when a legit push carries multiple releases. Also: gsp_rm_ev_{seq,nlist,cl} runtime knobs for the guest-RM event drop A/B (the r576 experiment: guest consumes every POST_EVENT record and never enters nv_post_event), and the GR-DEC launch dump now covers 256 data pages (the mail VADD fill carries n_data=969). New: tools/cuda-ab/evhold.cu - deterministic CUDA event holder/wait probe (context + cudaEventSynchronize + a hold window) for the event experiments.
* r576b diag: witness the recovery-release target (sema-fake lines)Arthur Hanson Rasmusson17 hours
| | | | | | | | | | | | | The r575 atomics wedge: a UVM tracker wait for payload 34 on its channel tracking semaphore stalled at 25 while the pump consumed the channel's remaining ring entries via the unreadable-entry grace/fake ladder and the client's wait never cleared (a manual exact-slot delivery of 34 via poke_guest unblocked it and the client completed green). The recovery release chosen by svc_fake_release is the suspect: its pool target is last_rel_va, learned from readable pushes, and a foreign release VA appearing there would send every later recovery to the wrong semaphore. Log every authored/queued recovery with its chosen target and payload (bounded, gsp_sema_dbg) so the next draw names the divergence.
* r576 diag: launch-decision + event-post payload witnesses ↵Arthur Hanson Rasmusson17 hours
| | | | | | | | | | | | | | | | | | | | | (gsp_phys_gr_dec_log, gsp_rm_ev_log) The GR launch-decision dump logs, for the first N draws whose fill saw dropped pages / a partial argument set or whose decision point carries a dstpend/copy-pending verdict: the decision verdicts, the launch's resolved data pages (VA -> guest PA), the live deferred-write records and the pending CE opdef entries - the operand evidence needed to explain a red draw of the readback lottery (the wrong-but-similar page hypothesis). The event-post witness logs every EVENT_POST_EVENT record actually sent with its full payload (hClient/hEvent/notifyIndex/data) and send result, plus a sentinel when post_all_events found valid events but posted none while none were dedup-skipped. This is the evidence needed when a client parks waiting for a completion wake-up that never arrives (the 2nd-client device-state spin): it shows whether the post was generated, for whom, and whether the status-queue write accepted it or dropped it (burst cap / ring full). Both are inert by default (budget 0).
* vgsp-sema r568: gate a partially-resolved launch on any unexecuted CE writeArthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | | | | | The page-level dstpend guard is blind when the launch's argument base was dropped (GRFILL-DROP): the launch's data set then lacks the buffer's pages. r571 mail: the VADD's copy-in ran at 319818.68 while the b H2D executed at 319820.16 (its base dropped, 9 pages unresolved) - the engine computed c = a + 0 again, same signature as r567/r568. r570 passed only because the page-level guard happened to catch it there. svc_copy_pending(): true when any active opdef slot belongs to a CE channel (a withheld CE release = a device write that has not executed; GR channels excluded so a launch's own withheld release cannot defer itself). A launch that is partially resolved (gr_arg_partial or gr_dropped > 0) now defers while any such write is pending, bounded by the same busy-defer + absolute 15 s cap machinery. Fully-resolved launches are unaffected (the page-level guard already covers them).
* vgsp-sema r567: a transfer-shaped push with no op notes its destination and ↵Arthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | | | | | | | | | stays owed The r569 mail failure's missing half: the b H2D's COPY op needs have_in (the staging upload), which was not resolved on the early passes, so the push decoded NO op; the release was still applied (the client's cudaMemcpy(b) returned at 318935) and the slot was marked complete, while the copy itself only executed at 318952 (17 s later) - the launch's copy-in (318945.7) read b = 0 and the engine computed c = a + 0 (readback src16 = a's values). The r541 guard had nothing to defer on (no op, no dstpend). A trusted, allow_ops, transfer-shaped push that decodes no op with a device destination now: - notes the destination via svc_dstpend_note (the launch guard defers until the copy runs or the 10 s window expires), and - sets svc.op_owed (the slot stays incomplete, so a later fresh pass runs the copy instead of replay-suppressing it forever). No hold is armed, so a push whose trust never arrives cannot wedge the pump; the guard provides the ordering, exactly like the r541 design.
* vgsp-sema r566: note a held entry's unexecuted device-dst copies for the ↵Arthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | | | | | | | launch guard Root cause (r567/r568, deterministic): the mail client's b H2D COPY op was COLLECTED but never attempted while its entry was held for another operand; the VADD launch's copy-in ran 0.6 s BEFORE the copy executed, so the engine read b = 0 and computed c = a + 0 (the readback page held a's values {0.0,0.5,1.0,1.5} vs the correct {0.0,0.75,1.5,2.25}). The r541 guard only saw copies that FAILED with -ENOENT (svc_dstpend_note at the failure site), so a merely PENDING copy was invisible to it. svc_dstpend_note_ops() runs after each svc_run_ops() call in svc_decode_stream whenever svc.op_tr_pending is set: every collected device-dst copy whose per-op done bit is not set (i.e. did not execute this pass or earlier) gets its destination noted. The launch guard then defers until the copy runs (the copy's success path clears the record), bounded by the existing dstpend TTL + busy-defer + 15 s cap machinery.
* vgsp-sema r565: session-scope the GR exactly-once caches (cross-client VA reuse)Arthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | The UVM pool reuses the same launch push VAs for every client of a boot. svc_gr_cap_hist[8] matches on the push VA ALONE (no content hash) and was boot-scoped, so a previous client's capture could classify a later client's fresh launch as already captured and skip it (LAUNCH-SKIP (replay; already captured=1) from a dead session's record). svc_gr_seen (hash-keyed) and svc_inline_once (content-keyed) share the same lifetime and the same class of risk. Reset all three in svc_session_flush; they refill within the session from the live client's own pushes, so same-session dedup is unchanged.
* vgsp-sema r563c: the stall watchdog gates on ACTIVE withheld work, not ↵Arthur Hanson Rasmusson18 hours
| | | | | | | | | | | | | | cumulative counters r566 evidence: the dump fired 4x with done=8929 and opdef=215/7/5 frozen while the ring was EMPTY (every channel last_get == put - the clients were waiting, no entry pending) and the forced flush had nothing to deliver: is a lifetime counter (215 holds applied/expired long ago), not proof of a current hold. A real stall has either a pending translation (svc_pending_n) or an ACTIVE opdef slot with releases recorded (e->active && e->n); the dump (and with it the self-heal arm) now requires one of those. The r564-class true stalls (active slots holding releases) still dump and still heal.
* vgsp-sema r563b: the stall self-heal clears the walk-state blockers (force ↵Arthur Hanson Rasmusson19 hours
| | | | | | | | | | | | | | | | | | | opdef flush + per-channel state) r564 evidence: the STALL-DUMPs fired (4x, done=12700 held=727 frozen) but ZERO STALL-HEAL lines - the force-consume budget never engaged because the walk breaks BEFORE the instrumented hold sites (the cheap-wait unread window at the loop top, or a stale GR hold/nocap index). The self-heal now acts on the state every break site consults: - svc_opdef_force_flush(): deliver every withheld release forward-only, record the delivered marks (so a re-decode cannot re-hold), clear the slots - the same edge the 3 s bound would run, at the watchdog's discretion; - per channel (under chan_lock): unread_va/unread_until = 0 (the cheap-wait break), gr_hold_idx/gr_hold_until/gr_nocap_idx/gr_nocap_va reset; - the force-consume budget stays as the belt for the hold sites. One loud STALL-HEAL line per firing.
* vgsp-sema r563: stall-watchdog self-heal (forced consume after 20 s of no ↵Arthur Hanson Rasmusson19 hours
| | | | | | | | | | | | | | | | | | | | | progress) Every remaining frozen-pump shape (r562: STALL-DUMP no entry consumed for 20 s, held=99 opdef=150/11/3 frozen, pool_dual=0 conflicts=1) has the same end state: some hold condition keeps winning and the walk breaks on the same entry forever, whichever hole was closed last (r548..r558 each closed one). Add the single backstop that cannot be out-run: when the r539 stall watchdog fires (20 s without consuming a GPFIFO entry while withheld work exists), arm a budget of 4 forced consumes; the next hold decisions that would park an entry are bypassed (opdef hold, no-capture hold, busy-defer re-hold, data-stalled hold), the entry is consumed with its withheld releases applied forward-only and the GR QMD completion authored by the existing tail, and the client's wait advances. Bounded by the dump cadence (<=4/boot) and the per-arming budget, so a healthy boot never sees it; each bypass logs one STALL-HEAL line. This turns 'the client stalls forever' into 'the client completes with the best-effort data the guards would have fallen back to anyway'.
* vgsp-sema r561: bound the pin-injection drain per service pass (starved ring ↵Arthur Hanson Rasmusson19 hours
| | | | | | | | | | | | | | | | | | walk) r559 soak2 evidence (victory_saxpy, 167 s at 100% CPU, module alive and printing stats but consuming no GPFIFO entries): the guest pin stream flooded the injection queue (svc_handle_map_add: 1867-6101 callbacks suppressed per burst, several bursts per 10 s) and the unbounded for(;;) drain spent every service pass processing injections, so the ring walk never ran - work_guard counters froze (deferred=513 applied=50 unchanged for minutes) and the client spun. Process at most 64 queued requests per svc_handle_map_add() call. The drain runs again on every service pass and from svc_gr_request/ svc_run_ops, so nothing is lost; under a flood the ring walk now gets its cycles every pass. Bounded batches are the same fairness rule the ring walk itself already uses.
* vgsp-sema r558: the opdef hold path honors the absolute per-launch boundArthur Hanson Rasmusson20 hours
| | | | | | | | | | | | | | r557 STALL-DUMP evidence (victory_matmul): "no GPFIFO entry consumed for 20s" repeated while opdef=3880/16/64 and held=155 climbed - the pump froze on one held entry whose operand never resolved, re-holding it every pass. The opdef hold was the only pump hold path without the absolute per-launch-VA bound (svc_gr_hold_bound_expired, the r509 one-shot used by every GR hold path); it could therefore extend indefinitely through fresh slot allocations even though each individual slot window is 3 s. Consult the same absolute bound before holding: once it fires the entry flushes its withheld releases and is consumed, so no operand-pending entry can freeze the pump's entry loop.
* vgsp-gr r556: absolute 15 s per-launch deferral cap (single stall backstop)Arthur Hanson Rasmusson20 hours
| | | | | | | | | | | | | | | | r553/r555 boots still show clients walking the individual defer/hold bounds for 400+ s: victory_reduce 430 s (same push VA re-deferred every pass, r554's 64-slot latch), victory_saxpy 254 s at write time with work_guard deferred climbing by the thousand. Each guard is bounded on its own, but their bounds interact and re-arm across re-decode passes. Arm an ABSOLUTE per-push-VA deadline on first sighting (64-slot table); once 15 s have passed, svc_gr_defer_expired() returns true and every defer site forwards best-effort: the r541 dstpend guard, the r543 arg-partial guard and the m150 data-stalled hold. 15 s sits far above the 0.5-2 s pin latency the deferrals exist to cover and far below every client-side timeout (>= 60 s), so the pin-late cases keep their window and no launch can be parked longer than the cap, whichever guard keeps winning.
* vgsp-gr r554: the per-VA launch-defer latch needs 64 slots, not 8Arthur Hanson Rasmusson20 hours
| | | | | | | | | | | | | r553 soak evidence (victory_reduce, 430 s stall, 0 hangs): the same launch push VA (0x20043be64) was deferred on every pass for 7+ minutes ("partial argument set: 7-8 pages unresolved"). A client's UVM pool allocates ~8-10 channels and each command buffer reuses two launch push slots, so more than 8 distinct push VAs rotate through the guard; with 8 latch slots each new VA evicted another and the one-deferral-per-VA guarantee thrashed - the second sighting of any VA found its record gone and deferred again, so a partial argument set that never resolves held the launch forever. 64 slots cover a full client with margin (1 KB of static state).
* vgsp-gr r553: the dstpend launch-defer window is absolute, not slidingArthur Hanson Rasmusson21 hours
| | | | | | | | | | | | | | | | | r551 soak evidence (victory_strided, same boot as a green battery): the client's init copies keep failing -ENOENT and are retried by the pump; every retry re-noted its destination page and re-freshened the r541 dstpend record, so svc_gr_dstpend_overlap() never lapsed and the launch guard deferred the launch forever: "GR busy-defer timeout -> hold 8000 ms" every ~4 s for 427 s, zero GR LAUNCH submitted, client at 100% CPU. Stamp a page's record once per failure episode: an existing record inside its 10 s window is not re-stamped (the window stays absolute from the first unexecuted write); an expired record is re-stamped for a genuinely new episode. The launch then forwards best-effort at the bound exactly as the guard's own comment promises ("bounded by the same busy-defer + gr_hold machinery ... it can never hang the launch").
* vgsp-sema r551: a delivered opdef release is not withheld again (kill the ↵Arthur Hanson Rasmusson22 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | | re-hold cycle) r550 evidence (victory_strided, reused CE channel 0x5c000059, init sequence with ~40 device-aperture fills whose walk fails -ENOENT): the sweep delivered each entry's withheld counter release every ~3 s and cleared the slot, the pump re-decoded the still-parked entry, svc_opdef_release recorded a FRESH slot and held it again - SWEEP-EXPIRED repeated six times for the same entry (entries 41..43 at ~18-21 s each) before OPDEF-EXPIRED consumed it; the client span at 100% CPU for 12+ min and the battery timed out (r549's 3 s bound alone only shrank, did not remove, the cycle). Remember every delivered release by (channel, entry, va, payload) in a bounded 256-slot / 60 s ring: - svc_opdef_release: a re-decode of an already-delivered release claims it (rel_seen bookkeeping stays correct) and does NOT re-record or hold; - svc_opdef_hold: an entry with any recent delivery is consumed, never held again; - svc_opdef_flush / expire_sweep record what they deliver; - the ring is per-session (svc_session_flush), because handles, ring slots and payload sequences are reused by the next client. Releases are monotonic completion signals and every delivery path is forward-only, so re-applying one is a no-op - the change cannot double anything, it only removes the re-hold.
* vgsp-sema r549: cap the dead-operand walk at 3 s per entry (opdef hold + ↵Arthur Hanson Rasmusson23 hours
| | | | | | | | | | | | | | | | | | | opfail window) r548 evidence (matmul, reused channel handle 0x5c000059 after the previous client exited): the new client's init sequence carries ~65 small device-destination ops whose operands no resolver covers (memcopy/memset rc=-2, SVC_VAS_FLOOR destinations like 0x2000c0100). Each one armed the opdef hold, expired after exactly 10 s (OPDEF-EXPIRED idx 7..18 at ~10.5 s spacing) and only then released the counter increment the client waits on: the pump walked one entry per 10 s while the client spun at 100 % CPU (12+ min, battery timeout). The two bounds were both 10000 ms. Ops that DO resolve show 0.5-2 s pin latency (SVC_OPDEF_HOLD_MS comment), so 3000 ms keeps the m163 guarantee (a failed device copy still gets its retry once the pins land) and the op-failure latch now fires on the first 3 s retry instead of a second 10 s window. Both are pure bounds - no path loses its retry.
* vgsp-sema r548: never consume a GR launch whose forward is still owed (r547 ↵Arthur Hanson Rasmusson23 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | saxpy stall) Live evidence (r547, 16+ min stuck victory_saxpy): both launches were captured, deferred by the r541 (unexecuted device write) and r543 (partial argument set) guards, and left as unoffered candidates - then every later pass re-decoded the entries as replays (LAUNCH-SKIP; already captured=1) and the consume path dropped them with no GR LAUNCH and no GR-COMPLETE-SW for the client, whose cudaDeviceSynchronize waited forever (client-side strace: RM-control poll loop, libcuda condvar 500 ms retimer; host log: consume idx=105/106 every ~2 s, releases never authored for rel=0x204827f7c). Three coordinated changes: - svc_gr_arg_defer_ok: per-VA latch table (8 slots) instead of a single slot. Two interleaved launches made the single slot ping-pong (each call saw the other VA and re-deferred both forever); each VA now gets exactly one deferral inside the 30 s window and the next sighting proceeds, so the guard delays without ever hanging. - svc_decode_stream: a fresh decode pass no longer wipes a valid, never-offered candidate (a deferred forward is not stale). The capture path already rotates to a free candidate-ring slot. - pump no-capture hold: fires for a REPLAY whose push VA still has an unoffered candidate in the ring (owed forward), forcing a fresh capture + request per bounded window; and when the window expires with the forward still owed, svc_gr_owed_resolve authors the QMD completion release from that candidate and marks it consumed, so an entry is never consumed without a completion (no late double-run). New counter gr_owed in the sema-svc drain line; hold log carries owed=.
* vgsp-sema r543: hold a GR forward with a partially-resolved argument set ↵Arthur Hanson Rasmusson24 hours
| | | | | | | | | | | | | | | | | | | | (bounded) The r542 matmul failure was the NOWRITE wedge: the fill resolved 969 pages but 2 of 13 high argument bases resolved 0 pages; with gsp_phys_gr_fill_hold=0 the fill is log-only for dropped pages and only the aggregate all-arguments-unresolved rule holds, so the launch forwarded, the engine fetched the QMD (qmd_rel=0x600df00d, engine fetch OK) and wrote nothing (retirement wait 0/1032, NOWRITE-AMBIGUOUS fe_esr=0x80000000, trap=0x80010250); the client read zeros (MATMUL bad=65536 csum=0). Fix: the fill now records gr_arg_partial when an ARGUMENT candidate page was dropped while other arguments resolved. svc_gr_request defers such a launch once per push VA (SVC_GR_ARG_DEFER_MS window, svc_gr_arg_defer_ok latch) through the existing bounded busy-defer retry, so the pins can land before the engine reads the operands. A genuinely junk pointer word pays the window once per push, not per retry; after the window the historical forward stands, so the guard can only delay a launch, never hang it.
* vgsp-sema r541: hold a GR forward whose data page has an unexecuted device writeArthur Hanson Rasmusson25 hours
| | | | | | | | | | | | | | | | | | | | | Live root cause of the smiley/streams2/streams_events readback lottery (r539): smiley pass 2 verified a2 + b1 and pass 4 verified a4 + b2 - each even pass's launch read the PREVIOUS even pass's b page. The b H2D's release completed the client's synchronous cudaMemcpy while the copy op itself was still held (b's svc_copy executed at 294026.818; launch 2's engine read at ~294026.3), so the client legitimately submitted the launch against a shadow page the H2D had not written yet. Passes 1/3 looked 'correct' only because passes 2 and 3 share the same b formula. Fix, as recommended in CONT.100/94: a device-dst copy/fill that fails to execute this pass (rc=-ENOENT) records its destination VA page in svc_dstpend[] with a 10 s stamp. svc_gr_request, right after the fill and before any submit, checks the launch's filled data pages against the table (svc_gr_dstpend_overlap); a hit returns the busy-defer verdict, so the pump holds the entry in its bounded retry window and re-captures once the copy has run - the record clears on the copy's success. The 10 s window restores the historical forward when the copy never lands, so the guard can only delay a launch, never hang it.
* vgsp-sema r540: a denied transfer op keeps its slot incomplete past the pend capArthur Hanson Rasmusson25 hours
| | | | | | | | | | | | | | | | | | | | | | The r539 boot showed the 5-minute device-init stall class live: a GRCE channel push (eng=0) carrying an H2D copy is decoded before the pin stream reaches its operands, so allow_ops=0 and the copy is denied; the r308 path sets op_tr_pending and holds the entry. That path is capped at 4 tries per slot ('so a slot whose trust never arrives cannot wedge the channel'), but once the cap is hit op_tr_pending stays 0 and svc_decode_stream's tail marks the slot COMPLETE - so every later pass classifies the entry as a replay and suppresses the copy forever. The pin arrives seconds later; the copy still never runs and the client spins at DEVICE until UVM's own retry. Evidence (r539, /tmp/opencode/r539-live.log): held idx 89/91..94 on h=0x5c000059 with 'denied ... replay=1 trusted=1' and 'sema-pend: hold ... idx=89' for minutes while the client printed DEVICE. Fix: new svc.op_owed flag. When the pend cap blocks the retry, the pass is marked owed so slot_ops_complete stays 0; the next fresh pass runs the copy as soon as the translation/injection exists. No hold is armed for an owed pass, so an operand that never translates still cannot wedge the pump (the denied path's liveness guarantee is preserved - only the freshness is).
* vgsp-sema r539: pool release fan-out to a second candidate page + STALL-DUMP ↵Arthur Hanson Rasmusson25 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | watchdog The init-stall boots (r530-r538) share one shape: the pump loops but the entry loop stops consuming, and a client spins in uvm channel_pool_add -> uvm_push_end_and_wait while its pool tracker word is frozen. The r538 live boot showed the cause live: va=0x121000000 flapped between the injected pin (the guest kernel's tracker->page->rm_mem chain) and the host GMMU walk on every resolve (pool-boot conflict ping-pong, ~50/s), and the release write follows whichever source answered that pass - a release written to the losing page strands the client that polls the other one. Fix: svc_pool_boot_store keeps BOTH most-recent distinct pages (primary + secondary, each with its own proof stamp). svc_pool_boot_fanout applies every successful pool release to the secondary as well (forward-only, read-back proven, 10 s freshness so a freed/reused page is never written). Wired into all three svc_sem_write success paths and svc_fake_release's recovery write. The r536 walk-over-pin preference stays as the primary choice; the pin is now recorded as the secondary there. Also: STALL-DUMP - when the entry loop consumes no entry for 20 s while withheld work exists (pending releases or opdef slots), dump the pending list, opdef slots, pool candidates and counters once (bounded 4/boot), so the next stall is named in one place instead of N bounded logs.
* vgsp-sema: bounded fallback registration for a parked VAS candidate (15 s)Arthur Hanson Rasmusson26 hours
| | | | | | | | | | | | The VAS candidate verification needs the client's ring to be found by the RAM content scan; on a boot where that never anchors the ring the candidate stays parked forever and every launch operand walk fails rc=-2 (observed: pd_found=0, vas[0] holding an internal pdb, walks stuck at 9555 successes with 114 K attempts while the client spun for minutes). After 15 s parked, register the candidate unverified with a loud log: it came from the client's own RM publish and the newest-first walk order keeps an older stale directory from winning, so the bounded wait's registration is the lesser evil.
* vgsp-sema: prefer the client's page tables over a disagreeing pool pin ↵Arthur Hanson Rasmusson26 hours
| | | | | | | | | | | | | | | | (moved-but-readable pool) The pool resolver trusted an injected pin after a read-back proof. That proof does not catch a pool page that MOVED: the old page is still readable, so the release write lands on the old page while the client polls the new one. Observed: 'pending release starved va=0x12100000x tries=64' for ~45 s with the stale pin (pa=0x120b30000) readable, until the fresh pin (pa=0x130e9d000) arrived; the client's tracker never woke and its init hung (multikernel battery timeout, copies stuck rc=-2). The client's own page tables are the GPU/UVM ground truth for where the tracker reads, so when a structural walk resolves a different page than the pin (and it is not a degenerate identity), the walk wins - both sources are read-back proven at the exact offset.
* vgsp-sema: chunk the discovery scan's guest reads (64 KB) - the rebuild was ↵Arthur Hanson Rasmusson27 hours
| | | | | | | | | | | | | starving the pump The full-RAM discovery scan read one 4 KB page per vfio_dma_rw call: 1.5 M guest reads over the 6 GB range, ~10-11 s per rebuild, and the rebuild runs every 10 s - so the pump got roughly one pass per rebuild. A client whose resolutions were dropped by a session flush then waited minutes for the scan to re-find its pages (the observed post-flush stall: data-VA copies returning -ENOENT with the pump counters frozen). Reading 64 KB chunks amortizes the iommu walk + pin over 16 pages; the per-page detection logic is unchanged.
* Revert "vgsp-sema: keep the learned VA map across the session flush ↵Arthur Hanson Rasmusson28 hours
| | | | | | (re-compact, not wipe)" This reverts commit 1a49c7eb69c03f58bc51939828de222a2ac42fea.
* vgsp-sema: keep the learned VA map across the session flush (re-compact, not ↵Arthur Hanson Rasmusson28 hours
| | | | | | | | | | | | | | | | | | wipe) The flush fires when the channel table momentarily empties - a live client's UVM channel cycling triggers it - and wiping the map left the client's already-resolved data VAs unresolvable until a rebuild scan re-found them, which it may not. Evidence: a mid-battery boot where multikernel's operands went NO ENTRY 40+ s after a flush (the rebuild restored 14-31 K entries without them); the pump stalled for minutes and the next clients read back whole-page garbage. The map is a cache with a merge-on-rebuild contract, so re-compact it (dedup + sort) and keep it as the merge base; reused-VA correctness stays with the ledger landing, the pin-wins rule and the fresh scan. Also: push_battery.sh now pushes inplace_scale (the battery list had it, the push list did not).
* r526 THE XDIFF ROOT CAUSE: the LOAD_INLINE_DATA destination cursor must ↵Arthur Hanson Rasmusson32 hours
| | | | advance even when the r391f once-only gate suppresses the write. A re-decode pass that skipped the FIRST run of a split upload left the cursor at the first run's destination, so the SECOND run's data landed at offset 0 (the deterministic tgemm X[0..1]<-X[2..3] 8-byte overwrite, present in every pass); the gate suppresses the write, not the method stream's positional semantics
* r510 keep the page-directory discovery attempts for coherent evidence: a ↵Arthur Hanson Rasmusson35 hours
| | | | | | | | | | | | | | large mixed-space map no longer burns them r508/r509 witness: 'page directory discovery: not found (base=0x0 ap=ram cands=39621 best=0/8)' during the very first client - eight RAM walks spent on a stride subsample of the boot-scoped map, which holds pairs from several VA spaces and (per the code's own comment) no single directory reproduces. By the time the push-buffer pairs - the strongest samples - formed, the attempts budget was gone; every later client's high argument pointers stayed unresolvable and the boot ended in the held-launch class. Only a small map (one session's own pairs) still falls back; a larger one waits for the pairs and keeps the attempts.
* r509 the GR data-hold bound can report expiry: one-shot verdict + latch, and ↵Arthur Hanson Rasmusson35 hours
| | | | | | | | | | | | | | | | | | the r351 retry-forward consumes it svc_gr_hold_bound_expired() re-armed the deadline on the very call that detected expiry and then compared jiffies against the NEW deadline - the function could never return true. A data-stalled launch whose arguments never resolve therefore held its entry forever (r508 witness: matmul plus ten sibling channels in 'GR hold ... data args unresolved' with zero GR-STALL-hold-bound lines for 10+ minutes; the designed one retry-forward plus consume never ran). The expiry is now one-shot: push the deadline, latch gr_hold_bound_hit (snapshot-persisted) for the second call site of the same pass, return true; the r351 retry-forward block consumes the latch and forces its single best-effort forward, and the NEXT expiry cycle (gr_hold_exp_logged now set) falls through to the historical consume with the software completion - a never-resolving launch now costs ~6 s and the client sees a stale-data FAIL instead of a hang.
* r507o walk the CE channels before the GR channels: enforce the client's ↵Arthur Hanson Rasmusson36 hours
| | | | | | | | | | | | | | | stream order in the pump itself The streams order their H2D copies before the kernel that consumes them, but the channels register in handle order (the RM's GR channel early, the copy-CE channels later) and the pump walked them in that order; a pass that decoded the GR launch before the CE channel's entries ran let the forward workqueue execute the launch's copy-in against pre-copy data (r480-sep: copy-in 115 ms before its stream's H2D soft copies; r481 proved no host semaphore links the two). The CE copies execute on the same service thread, so consuming the CE entries first fixes the inversion without any cross-channel hold. Stable partition of the pass snapshot; relative order within each class is preserved.
* r507a op-failure latch is time-based: a full opdef window before it stops ↵Arthur Hanson Rasmusson36 hours
| | | | | | | | | | | | holding (r507 matmul lost a pin-late 1 MB UVA copy and verified FAIL) r506w's attempt-count latch tripped after 8 fast passes (~100 ms) while the legitimate pin-late retry needs 0.5-2 s (r507 witness: memcopy dst=0x71365ee02200 src=0x71365e500000 bytes=1048576 rc=-2 skipped; matmul completed with STATUS FAIL instead of hang). The first failure of a VA now arms a full 10000 ms window during which the op holds its entry exactly as before; only after a full bound with no success does the op stop forcing the hold. A success clears the record (fresh window on a later failure).
* r506w kill the r505/r506 post-DEVICE grind: bounded op-failure latch + exact ↵Arthur Hanson Rasmusson36 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | release routing Two independent defects turned one unresolvable virtual op into a client-wide hang (r505 multikernel, r506 matmul: 'client at DEVICE forever' while the pump ground its stream at ~10 s per push): - an op that keeps failing -ENOENT re-runs on every decode pass and re-set svc.op_tr_pending each time, so its push held for the full SVC_OPDEF_HOLD_MS opdef bound every pass (r506 witness: the RM's channel-progress zeroing at 0x2000c0xxx, 1913 failed attempts, 65 ring entries in ~90 s). New per-VA failure latch: after 8 failures the op still attempts its write but stops forcing the hold; the entry consumes and its withheld release applies - exactly the outcome the expired bound already sanctioned, minus the 10 s tax. - svc_rel_apply_launch routed EVERY release through the exact-slot counter fallback (release_pa ?: counter_pa), which writes (and forward-only-skips against) the channel's registered completion slot - a different word. The tracker releases to 0x20480fef0 were skipped against the polluted PUT counter (cur=96) and lost: rel-apply h=0x5c000059 pa=0x10809def0 pay=1 cur=96 -> skip. The fallback is now restricted to counter VAs; generic releases are forward-only by value (payload > fresh cur) so a decode blinded by a stale landing can no longer drop them.
* r505b opdef flush marks the slot complete; bound the slot arrays for large ringsArthur Hanson Rasmusson40 hours
| | | | | | | | | | | | | | | Two fixes for the r505 multikernel livelock (opdef held=18359, expired=61, client at DEVICE forever while the pump looped on ring slot 1): - after the bounded opdef hold expires and svc_opdef_flush delivers the withheld releases, the slot's ops are permanently skipped - but the decode-time bookkeeping had stored slot_ops_complete=0 (op_tr_pending was set when it ran), so every pin-batch rewind replay of the slot re-decoded it, re-set op_tr_pending and re-held the entry forever. Mark the slot complete on flush so a replay suppresses the ops (entry_replay) and the entry consumes normally. - the per-slot op arrays are SVC_GPFIFO_MAX_BITS (1024) but the X/GL channel's ring is 8192 slots: bound every slot-index write/read (entry_ident is zeroed past the array size, so the bookkeeping skips).
* r496j VAS candidates are registered only after a content-verified ring walk ↵Arthur Hanson Rasmusson40 hours
| | | | | | | | | | | | | | | | | | | | (+3 fixes) The r496g blast registration of every COPY_SERVER_PDES directory let a stale kernel directory answer another client's VA in the walker's first-success order (the r459 stale-directory class) - measured as a CUDA client hanging after DEVICE. Candidates are now parked and registered only when a walk of the client's own content-validated ring VA through them reproduces that ring's PA; the r496f vidmem sweep remains as a fallback. Also in this batch: - svc_chan_userd's VRAM shape scan now prefers a block with work PENDING (get < put) and then the one nearest the registered memdesc offset: on a channel re-registration the stale previous USERD still validates (it holds the same put/entry values) and the old first-match adoption made the pump write GP_GET into the dead block (r504 second DMA init). - The USERD/FB scan and the CE caps byte-1 BL bits (r496i) are unchanged; TU104_CE_CAPS1 = 0x03 needs the CUDA battery re-verification.
* r496h do not pin a linear window for content-scanned rings; the VAS walk ↵Arthur Hanson Rasmusson41 hours
| | | | | | | | | | | resolves the rest The registered COPY_SERVER_PDES directory walks the ring VA correctly (trace: L0 -> L1 -> L2 idx 9 -> PD0), but the linear window pin installed around the ring shadows it in svc_lookup_trusted (pin_lookup_any returns the win-flagged entry first), so the pushbuffer/tracker reads kept using the wrong noncontiguous guess. Pin only the content-validated ring page; every other VA of the client now resolves through the walk.
* r496f discover the kernel-RM client VAS page directory by verificationArthur Hanson Rasmusson41 hours
| | | | | | | | | | | | | | The X/GL channel's pushbuffer pages and progress semaphore live in a kernel-RM internal VAS whose page directory is never published (fn 54 is UVM/external-VAS only), so no translation source can resolve them: the tracker push reads zeros/garbage and the driver's DMA sanity poll (which waits on the progress-tracker semaphore the GPU writes when it consumes the tracker push) never completes. With the ring content-validated, try each 4 KB page of the vidmem shadow as a walk root and register the first whose walk reproduces the ring VA -> ring PA translation. The walker then resolves every other VA of the same client - pushbuffer pages, the tracker push, the progress semaphore.
* r496e the X NOP push: all-zero accepted on content-scanned channels; no ↵Arthur Hanson Rasmusson41 hours
| | | | | | | | | | | | | capture holds for their entries The driver's __nvPushTestPushBuffer writes one zero dword (NVA06F_DMA_NOP) and waits for GP_GET to follow GP_PUT. The method-stream plausibility gate rejects an all-zero buffer (it parses as zero methods), so the entry fell into the unreadable/rescue path and the GR no-capture hold - the DMA sanity test could never pass. For channels whose ring was found by the RAM content scan (kernel-RM sysmem 3D channels), model them as consume-and-apply- releases: accept an all-zero NOP push, and skip the no-capture hold (these pushes are not compute launches; holding them 6 s per entry cannot help).
* r496d USERD shape-scan validation: the progress-tracker entry sits ABOVE the ↵Arthur Hanson Rasmusson42 hours
| | | | | | | | | ring The ring-ownership check rejected every entry VA >= ring_va, but the driver writes TWO GPFIFO entries per kickoff - the main pushbuffer BELOW the ring and the progress tracker ABOVE it (nvidia-push-priv.h). Accept VAs anywhere in the 2 MB allocation window.
* r496c RAM-scan cursor must persist through the stalled-userd continueArthur Hanson Rasmusson42 hours
| | | | | | | The pump's !userd_ok path continues past the end-of-pass write-back, so the GR RAM ring scan restarted from slice 0 every pass and never reached the ring page beyond the first 512 MB. Persist gr_ram_cursor/gr_ram_passes (and the one-shot log flag) directly in the scan.
* r496b the X/GL channel bring-up: sysmem ring discovery by content + VRAM ↵Arthur Hanson Rasmusson42 hours
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | USERD shape scan With the GR classification fixed the pump reaches the X driver's 3D channel for the first time, but both of its structures are outside every existing translation source: the CPU RM maps the pushbuffer's NV01_MEMORY_SYSTEM surface locally (no SET_PAGE_DIRECTORY, no rm_mem record carrying the ring VA - the targeted resolve scans all of guest RAM and finds nothing), and the driver's USERD GP_PUT write lands in the emulated VRAM at a BAR1-window offset (observed: fb 0x80000) that is neither the registered memdesc base (0x10000, pool-relative) nor ring-derived. Two content scans close the gap, both validated so a wrong hit costs a failed probe, not a bad pin: - svc_gr_ram_ring_scan: the driver's kickoff writes GPFIFO entries whose pushbuffer VAs sit just BELOW the ring VA in the same allocation (main pushbuffer first, GPFIFO after - nvidia-push-priv.h). A page whose first two 8-byte entries both name such VAs with sane lengths is the ring; the ring page is pinned validated and the 2 MB allocation window as guesses (the ring entry and pushbuffer reads resolve through it). Sliced 512 MB per pass, cursor-resumed, 16 slices max. - svc_userd_fb_scan (svc_chan_userd GR fallback): scan the VRAM for the USERD shape (GP_PUT at +0x8c in [1..entries], GP_GET at +0x88 <= put) and validate each hit against the ring: every entry the put claims must decode to a pushbuffer VA in the ring's allocation window. A foreign channel's USERD cannot pass that test. 8 bounded retries (the kickoff lands a few passes after registration).
* r484 the staging-drain completion edge: when the acquire gate holds an entry ↵Arthur Hanson Rasmusson45 hours
| | | | (its op may have already run on an earlier gate-less decode), force exactly one op re-run on the first pass whose gate finally passes - the pass at which the dependency just became installed. Without it the once-only done bitmap suppressed the op and the release applied while the staging still held the pre-dependency bytes (streams_events s=2: the D2H read dc2 before the vadd_into wrote it, ran early, was skipped when the wait passed, and the guest drained a2+b2 instead of a2+b2+c1)
* r481c sema_push_raw: lower the call-site threshold to 512 bytes so launch ↵Arthur Hanson Rasmusson45 hours
| | | | pushes (872/888B) dump; runtime-enable before the client run to avoid boot noise
* r481b sema_push_raw walk fix: handle op!=1 method groups (data runs, scans) ↵Arthur Hanson Rasmusson45 hours
| | | | and bound to launch-sized pushes (512..8192 bytes) so the launch method stream dumps cleanly
* r481 sema_push_raw diagnostic: dump the decoded method stream of the first N ↵Arthur Hanson Rasmusson45 hours
| | | | large GR-class pushes (default 0 off, no behaviour change) so the launch push's acquire/release method groups are visible verbatim; needed to prove which ordering mechanism the driver relies on for async-stream H2D -> kernel dependencies (streams_events st2 vadd copy-in ran ~115 ms before its stream's H2D soft copies)
* r471 the counter-publish clamp: never advance the guest's completion word ↵Arthur Hanson Rasmusson46 hours
| | | | past a push whose content was still unwritten when its entry was consumed. The r477 failing probe run showed the reuse hazard directly: the channel registered with a residual USERD put (4) and ring slots 1-3 all-zero; the pump consumed them (the r470 hold only delays) and the end-of-pass publish then wrote val=2 while the client's own counter was still 1 - the D2H wait was satisfied before the copy ran and the readback drained a reused staging buffer holding the PREVIOUS copy's bytes (h_c[2] = c0's data). New per-channel gr_bad_put (lowest all-zero GR slot + 1, persisted in the pump write-back): set when a zero-content GR entry is held/consumed, cleared when a decode reads non-zero content (the rewinds re-read entries constantly, so it heals within passes); svc_counter_publish clamps val to it with a bounded pub-clamp witness.
* r470 the narrow streams_events stale-ring fix: an ALL-ZERO push page (ring ↵Arthur Hanson Rasmusson47 hours
| | | | entry written - previous session's or the client's own slot reuse - but the push content not yet landed) is held by the m164 GR no-capture window instead of being consumed as a no-op, so the end-of-pass counter publish cannot advance the guest's completion word before the real push is read (streams_events: h_c[2] = c0 because the c2 D2H completion was published 4.5 s before its copy ran). Deliberately narrower than the reverted r469 plausibility verdict: compute-class GR pushes legitimately fail the CE-shaped method matcher, so only an entirely zero page counts as unwritten (r469's broad hold delayed GR config pushes and triggered the engine-fetch-NONE wedge on the first client).
* Revert "r469 THE streams_events staging-reuse corruption root cause: a GR ↵Arthur Hanson Rasmusson47 hours
| | | | | | entry whose push content is implausible (unwritten / previous-epoch page, no QMD word seen) was consumed as a no-op and the end-of-pass counter publish then advanced the guest's completion word while the real push had never been read - the client drained a staging buffer that still held the PREVIOUS copy's bytes (probe run: BUF s=2 got=c0's 0,0.75,1.5.. instead of c2's 3.0,5.25,7.5..; log: 'pub-adv h=0x5c000062 val=4 cur=1' at 210741.947, 4.5 s before the c2 D2H copy executed at 210746.371, with the ring slots decoded as zero-content pushes at 210736). The implausible-content read now feeds the m164 GR no-capture hold (bounded gsp_sema_gr_nocap_hold_ms window, rehold forces a fresh capture): the entry stays unconsumed, the publish gate (last_get != put) suppresses the early completion, and the retry reads the client's real push once it lands. Plausible fallback reads (validated pin / displaced pair) clear the flag." This reverts commit 349ee341539a0c1e9e3be11563251589eb42f8a8.
* r469 THE streams_events staging-reuse corruption root cause: a GR entry ↵Arthur Hanson Rasmusson48 hours
| | | | whose push content is implausible (unwritten / previous-epoch page, no QMD word seen) was consumed as a no-op and the end-of-pass counter publish then advanced the guest's completion word while the real push had never been read - the client drained a staging buffer that still held the PREVIOUS copy's bytes (probe run: BUF s=2 got=c0's 0,0.75,1.5.. instead of c2's 3.0,5.25,7.5..; log: 'pub-adv h=0x5c000062 val=4 cur=1' at 210741.947, 4.5 s before the c2 D2H copy executed at 210746.371, with the ring slots decoded as zero-content pushes at 210736). The implausible-content read now feeds the m164 GR no-capture hold (bounded gsp_sema_gr_nocap_hold_ms window, rehold forces a fresh capture): the entry stays unconsumed, the publish gate (last_get != put) suppresses the early completion, and the retry reads the client's real push once it lands. Plausible fallback reads (validated pin / displaced pair) clear the flag.
* r459 THE mid-boot degradation root cause: the 8-slot VA-space table filled ↵Arthur Hanson Rasmusson2 days
| | | | | | | | | | | | | | | | | | | | | | | | | | with dead clients' registrations and every new client after the 8th got no slot Evidence (r466 boot, one battery): 23 distinct 'VA space 0x... page directory ... entries=4' registrations and ZERO 'VA space ... dropped' lines. The guest driver does not always tear a client's VA space down (client exit, crash, or a switch the RM emulation does not forward), so after eight registrations svc.vas[] had no free slot: gsp_sema_service_vaspace_add silently refused the new directory (the 'if (vs)' guard), svc_walk_vaspaces kept walking only the dead clients' directories, and every walk of the new client's VAs failed -> its CE copies returned rc=-2 forever ('sema-optrace ... rc=-2' x8151 in the r466 log; the 10th+ client of the boot: streams2 bad=32737, streams_events no output, smiley hung, and the same class on r463/r465). This is the 'no launch stalls / no mid-boot degradation' blocker. Fix: - svc_vaspace_add evicts the least-recently-registered entry when the table is full instead of refusing (logged), and stamps every registration; - svc_walk_vaspaces orders the snapshot by registration stamp, newest first, so a live client's directory is the authority and a stale one (whose guest memory the driver has since reused) can only answer when the live directory cannot.
generated by cgit v1.2.3 (git 2.39.1) at 2026-10-24 15:25:43 +0000