[master] a63b4a53b obj: Rush objcores based on BOC state changes

[Dridi Boukelmoune]

commit a63b4a53b40d5b7365e3cdcdbe851c2542532c90
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Mon Jan 22 14:58:27 2024 +0100

    obj: Rush objcores based on BOC state changes
    
    The BOS_PREP_STREAM state is retired. It was used as a stop-gap to
    "unbusy" objects before waking up the client task for good. Instead,
    the HSH_Unbusy() and HSH_Fail() functions are called once the gap is
    closed, depending on the outcome.
    
    This removes one unnecessary signal and consolidates multiple call
    sites, ensuring that objects always drop the OC_F_BUSY flag from a
    central location, for fetch tasks.

diff --git a/bin/varnishd/cache/cache_fetch.c b/bin/varnishd/cache/cache_fetch.c
index 79798847d..f00516812 100644
--- a/bin/varnishd/cache/cache_fetch.c
+++ b/bin/varnishd/cache/cache_fetch.c
@@ -712,11 +712,8 @@ vbf_stp_fetch(struct worker *wrk, struct busyobj *bo)
 
 	assert(oc->boc->state == BOS_REQ_DONE);
 
-	if (bo->do_stream) {
-		ObjSetState(wrk, oc, BOS_PREP_STREAM);
-		HSH_Unbusy(wrk, oc);
+	if (bo->do_stream)
 		ObjSetState(wrk, oc, BOS_STREAM);
-	}
 
 	VSLb(bo->vsl, SLT_Fetch_Body, "%u %s %s",
 	    bo->htc->body_status->nbr, bo->htc->body_status->name,
@@ -751,11 +748,8 @@ vbf_stp_fetchend(struct worker *wrk, struct busyobj *bo)
 
 	if (bo->do_stream)
 		assert(oc->boc->state == BOS_STREAM);
-	else {
+	else
 		assert(oc->boc->state == BOS_REQ_DONE);
-		ObjSetState(wrk, oc, BOS_PREP_STREAM);
-		HSH_Unbusy(wrk, oc);
-	}
 
 	ObjSetState(wrk, oc, BOS_FINISHED);
 	VSLb_ts_busyobj(bo, "BerespBody", W_TIM_real(wrk));
@@ -884,11 +878,8 @@ vbf_stp_condfetch(struct worker *wrk, struct busyobj *bo)
 		ObjSetFlag(bo->wrk, oc, OF_IMSCAND, 0);
 	AZ(ObjCopyAttr(bo->wrk, oc, stale_oc, OA_GZIPBITS));
 
-	if (bo->do_stream) {
-		ObjSetState(wrk, oc, BOS_PREP_STREAM);
-		HSH_Unbusy(wrk, oc);
+	if (bo->do_stream)
 		ObjSetState(wrk, oc, BOS_STREAM);
-	}
 
 	INIT_OBJ(vop, VBF_OBITER_PRIV_MAGIC);
 	vop->bo = bo;
@@ -1038,8 +1029,6 @@ vbf_stp_error(struct worker *wrk, struct busyobj *bo)
 	assert(o == VSB_len(synth_body));
 	AZ(ObjSetU64(wrk, oc, OA_LEN, o));
 	VSB_destroy(&synth_body);
-	ObjSetState(wrk, oc, BOS_PREP_STREAM);
-	HSH_Unbusy(wrk, oc);
 	if (stale != NULL && oc->ttl > 0)
 		HSH_Kill(stale);
 	ObjSetState(wrk, oc, BOS_FINISHED);
@@ -1060,9 +1049,8 @@ vbf_stp_fail(struct worker *wrk, struct busyobj *bo)
 	CHECK_OBJ_NOTNULL(oc, OBJCORE_MAGIC);
 
 	assert(oc->boc->state < BOS_FINISHED);
-	HSH_Fail(wrk, oc);
-	HSH_Kill(oc);
 	ObjSetState(wrk, oc, BOS_FAILED);
+	HSH_Kill(oc);
 	return (F_STP_DONE);
 }
 
diff --git a/bin/varnishd/cache/cache_obj.c b/bin/varnishd/cache/cache_obj.c
index 4c40d3b8d..172e29a8b 100644
--- a/bin/varnishd/cache/cache_obj.c
+++ b/bin/varnishd/cache/cache_obj.c
@@ -86,6 +86,7 @@
 
 #include "cache_varnishd.h"
 #include "cache_obj.h"
+#include "cache_objhead.h"
 #include "vend.h"
 #include "storage/storage.h"
 
@@ -490,8 +491,7 @@ ObjVAICancel(struct worker *wrk, struct boc *boc, struct vai_qe *qe)
  */
 
 void
-ObjSetState(struct worker *wrk, const struct objcore *oc,
-    enum boc_state_e next)
+ObjSetState(struct worker *wrk, struct objcore *oc, enum boc_state_e next)
 {
 	const struct obj_methods *om;
 
@@ -500,7 +500,6 @@ ObjSetState(struct worker *wrk, const struct objcore *oc,
 	assert(next > oc->boc->state);
 
 	CHECK_OBJ_ORNULL(oc->stobj->stevedore, STEVEDORE_MAGIC);
-	assert(next != BOS_STREAM || oc->boc->state == BOS_PREP_STREAM);
 	assert(next != BOS_FINISHED || (oc->oa_present & (1 << OA_LEN)));
 
 	if (oc->stobj->stevedore != NULL) {
@@ -509,6 +508,11 @@ ObjSetState(struct worker *wrk, const struct objcore *oc,
 			om->objsetstate(wrk, oc, next);
 	}
 
+	if (next == BOS_FAILED)
+		HSH_Fail(wrk, oc);
+	else if (oc->boc->state < BOS_STREAM && next >= BOS_STREAM)
+		HSH_Unbusy(wrk, oc);
+
 	Lck_Lock(&oc->boc->mtx);
 	oc->boc->state = next;
 	obj_boc_notify(oc->boc);
diff --git a/bin/varnishd/cache/cache_varnishd.h b/bin/varnishd/cache/cache_varnishd.h
index 572ad2a0b..1e00b4004 100644
--- a/bin/varnishd/cache/cache_varnishd.h
+++ b/bin/varnishd/cache/cache_varnishd.h
@@ -342,8 +342,7 @@ int ObjGetSpace(struct worker *, struct objcore *, ssize_t *sz, uint8_t **ptr);
 void ObjExtend(struct worker *, struct objcore *, ssize_t l, int final);
 uint64_t ObjWaitExtend(const struct worker *, const struct objcore *,
     uint64_t l, enum boc_state_e *statep);
-void ObjSetState(struct worker *, const struct objcore *,
-    enum boc_state_e next);
+void ObjSetState(struct worker *, struct objcore *, enum boc_state_e next);
 void ObjWaitState(const struct objcore *, enum boc_state_e want);
 void ObjTouch(struct worker *, struct objcore *, vtim_real now);
 void ObjFreeObj(struct worker *, struct objcore *);
diff --git a/include/tbl/boc_state.h b/include/tbl/boc_state.h
index 44984de81..2e0413660 100644
--- a/include/tbl/boc_state.h
+++ b/include/tbl/boc_state.h
@@ -32,7 +32,6 @@
 
 BOC_STATE(INVALID,	invalid)	/* don't touch (yet) */
 BOC_STATE(REQ_DONE,	req_done)	/* bereq.* can be examined */
-BOC_STATE(PREP_STREAM,	prep_stream)	/* Prepare for streaming */
 BOC_STATE(STREAM,	stream)		/* beresp.* can be examined */
 BOC_STATE(FINISHED,	finished)	/* object is complete */
 BOC_STATE(FAILED,	failed)		/* something went wrong */