On 1/13/2022 12:30, Matthew Brost wrote:
Seems unlikely we are going that big any time soon. And such stack reduction can always be done as part of any huge engine count update. Although, this is userland not kernel - you can slap gigabytes on the stack and it won't blow up ;).On Thu, Jan 13, 2022 at 11:59:41AM -0800, John.C.Harrison@xxxxxxxxx wrote:From: John Harrison <John.C.Harrison@xxxxxxxxx> The hang test was relying on context persitence for no particular reason. That is, it would set a bunch of background spinners running then immediately destroy the active contexts but expect the spinners to keep spinning. With the current implementation of context persistence in i915, that means that super high priority pings are sent to each engine at the start of the test. Depending upon the timing and platform, one of those unexpected pings could cause test failures. There is no need to require context persitence in this test. So change to managing the contexts cleanly and only destroying them when they are no longer in use. Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx> --- tests/i915/i915_hangman.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/tests/i915/i915_hangman.c b/tests/i915/i915_hangman.c index 918418760..6601db5f6 100644 --- a/tests/i915/i915_hangman.c +++ b/tests/i915/i915_hangman.c @@ -289,27 +289,29 @@ test_engine_hang(const intel_ctx_t *ctx, const struct intel_execution_engine2 *e, unsigned int flags) { const struct intel_execution_engine2 *other; - const intel_ctx_t *tmp_ctx; + const intel_ctx_t *local_ctx[GEM_MAX_ENGINES];This is fine for now as GEM_MAX_ENGINES is relatively small but what if we change this to large value, let's say 4k? I think the stack could overflow then. Maybe not a concern, maybe it is? I'll leave this up to if this should be kmalloc'd or not in the next rev.
John.
Everything else looks good. With that: Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>igt_spin_t *spin, *next; IGT_LIST_HEAD(list); uint64_t ahnd = get_reloc_ahnd(device, ctx->id), ahndN; + int num_ctx;igt_skip_on(flags & IGT_SPIN_INVALID_CS &&gem_engine_has_cmdparser(device, &ctx->cfg, e->flags));/* Fill all the other engines with background load */+ num_ctx = 0; for_each_ctx_engine(device, ctx, other) { if (other->flags == e->flags) continue;- tmp_ctx = intel_ctx_create(device, &ctx->cfg);- ahndN = get_reloc_ahnd(device, tmp_ctx->id); + local_ctx[num_ctx] = intel_ctx_create(device, &ctx->cfg); + ahndN = get_reloc_ahnd(device, local_ctx[num_ctx]->id); spin = __igt_spin_new(device, .ahnd = ahndN, - .ctx = tmp_ctx, + .ctx = local_ctx[num_ctx], .engine = other->flags, .flags = IGT_SPIN_FENCE_OUT); - intel_ctx_destroy(device, tmp_ctx); + num_ctx++;igt_list_move(&spin->link, &list);} @@ -339,7 +341,10 @@ test_engine_hang(const intel_ctx_t *ctx, igt_spin_free(device, spin); put_ahnd(ahndN); } + put_ahnd(ahnd); + while (num_ctx) + intel_ctx_destroy(device, local_ctx[--num_ctx]);check_alive();} -- 2.25.1
