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Commit a1e3ed99 authored by Poul-Henning Kamp's avatar Poul-Henning Kamp
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Apply the "alexandrian solution" to cache_center.c and split the 

state engine into two separate state engines, one for session
and one for requests.

Next comes the cleanup of all the bits and pieces...
parent 7d9ca7de
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Showing with 212 additions and 153 deletions
bin/varnishd/cache/cache.h
View file @ a1e3ed99
......@@ -736,7 +736,8 @@ void VBO_DerefBusyObj(struct worker *wrk, struct busyobj **busyobj);
void VBO_Free(struct busyobj **vbo);
/* cache_center.c [CNT] */
void CNT_Session(struct sess *sp);
int CNT_Request(struct req *);
void CNT_Session(struct sess *);
void CNT_Init(void);
/* cache_cli.c [CLI] */
......
bin/varnishd/cache/cache_center.c
View file @ a1e3ed99
......@@ -26,12 +26,21 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file contains the central state machine for pushing requests.
* This file contains the two central state machine for pushing
* sessions and requests.
*
* We cannot just use direct calls because it is possible to kick a
* request back to the lookup stage (usually after a rewrite). The
* state engine also allows us to break the processing up into some
* logical chunks which improves readability a little bit.
* The first part of the file, entrypoint CNT_Session() and down to
* the ==== separator, is concerned with sessions. When a session has
* a request to deal with, it calls into the second half of the file.
* This part is for all practical purposes HTTP/1.x specific.
*
* The second part of the file, entrypoint CNT_Request() and below the
* ==== separator, is intended to (over time) be(ome) protocol agnostic.
* We already use this now with ESI:includes, which are for all relevant
* purposes a different "protocol"
*
* A special complication is the fact that we can suspend processing of
* a request when hash-lookup finds a busy objhdr.
*
* Since the states are rather nasty in detail, I have decided to embedd
* a dot(1) graph in the source code comments. So to see the big picture,
......@@ -203,6 +212,175 @@ cnt_wait(struct sess *sp, struct worker *wrk, struct req *req)
return (1);
}
/*--------------------------------------------------------------------
* This is the final state, figure out if we should close or recycle
* the client connection
*
DOT DONE [
DOT shape=record
DOT label="{cnt_done:|Request completed}"
DOT ]
DOT ESI_RESP [ shape=hexagon ]
DOT DONE -> start [label="full pipeline"]
DOT DONE -> wait
DOT DONE -> ESI_RESP
*/
static int
cnt_done(struct sess *sp, struct worker *wrk, struct req *req)
{
double dh, dp, da;
int i;
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
CHECK_OBJ_ORNULL(req->vcl, VCL_CONF_MAGIC);
AZ(req->obj);
AZ(req->busyobj);
req->director = NULL;
req->restarts = 0;
/* If we did an ESI include, don't mess up our state */
if (req->esi_level > 0)
return (1);
if (req->vcl != NULL) {
if (wrk->vcl != NULL)
VCL_Rel(&wrk->vcl);
wrk->vcl = req->vcl;
req->vcl = NULL;
}
sp->t_idle = W_TIM_real(wrk);
if (req->xid == 0) {
req->t_resp = sp->t_idle;
} else {
dp = req->t_resp - req->t_req;
da = sp->t_idle - req->t_resp;
dh = req->t_req - sp->t_open;
/* XXX: Add StatReq == StatSess */
/* XXX: Workaround for pipe */
if (sp->fd >= 0) {
VSLb(req->vsl, SLT_Length, "%ju",
(uintmax_t)req->req_bodybytes);
}
VSLb(req->vsl, SLT_ReqEnd, "%u %.9f %.9f %.9f %.9f %.9f",
req->xid, req->t_req, sp->t_idle, dh, dp, da);
}
req->xid = 0;
VSL_Flush(req->vsl, 0);
req->t_req = NAN;
req->t_resp = NAN;
req->req_bodybytes = 0;
req->hash_always_miss = 0;
req->hash_ignore_busy = 0;
if (sp->fd >= 0 && req->doclose != NULL) {
/*
* This is an orderly close of the connection; ditch nolinger
* before we close, to get queued data transmitted.
*/
// XXX: not yet (void)VTCP_linger(sp->fd, 0);
SES_Close(sp, req->doclose);
}
if (sp->fd < 0) {
wrk->stats.sess_closed++;
SES_Delete(sp, NULL, NAN);
return (1);
}
if (wrk->stats.client_req >= cache_param->wthread_stats_rate)
WRK_SumStat(wrk);
WS_Reset(req->ws, NULL);
WS_Reset(wrk->aws, NULL);
i = HTC_Reinit(req->htc);
if (i == 1) {
req->t_req = sp->t_idle;
wrk->stats.sess_pipeline++;
sp->step = STP_START;
} else {
sp->t_rx = sp->t_idle;
req->t_req = NAN;
if (Tlen(req->htc->rxbuf))
wrk->stats.sess_readahead++;
sp->step = STP_WAIT;
}
return (0);
}
/*--------------------------------------------------------------------
*/
void
CNT_Session(struct sess *sp)
{
int done;
struct worker *wrk;
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
wrk = sp->wrk;
CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
/*
* Whenever we come in from the acceptor or waiter, we need to set
* blocking mode, but there is no point in setting it when we come from
* ESI or when a parked sessions returns.
* It would be simpler to do this in the acceptor or waiter, but we'd
* rather do the syscall in the worker thread.
* On systems which return errors for ioctl, we close early
*/
if (sp->step == STP_WAIT && VTCP_blocking(sp->fd)) {
if (errno == ECONNRESET)
SES_Close(sp, "remote closed");
else
SES_Close(sp, "error");
assert(cnt_done(sp, wrk, sp->req) == 1);
return;
}
while (1) {
/*
* Possible entrance states
*/
assert(
sp->step == STP_WAIT ||
sp->step == STP_LOOKUP ||
sp->step == STP_START ||
sp->step == STP_RECV);
if (sp->step != STP_WAIT) {
done = CNT_Request(sp->req);
if (done == 2)
return;
assert(done == 1);
}
if (sp->step == STP_DONE) {
done = cnt_done(sp, wrk, sp->req);
if (done)
return;
}
if (sp->step == STP_WAIT) {
done = cnt_wait(sp, wrk, sp->req);
if (done)
return;
}
}
}
/*====================================================================*/
/*--------------------------------------------------------------------
* We have a refcounted object on the session, and possibly the busyobj
* which is fetching it, prepare a response.
......@@ -370,116 +548,8 @@ cnt_deliver(struct sess *sp, struct worker *wrk, struct req *req)
(void)HSH_Deref(&wrk->stats, NULL, &req->obj);
http_Teardown(req->resp);
sp->step = STP_DONE;
return (0);
}
/*--------------------------------------------------------------------
* This is the final state, figure out if we should close or recycle
* the client connection
*
DOT DONE [
DOT shape=record
DOT label="{cnt_done:|Request completed}"
DOT ]
DOT ESI_RESP [ shape=hexagon ]
DOT DONE -> start [label="full pipeline"]
DOT DONE -> wait
DOT DONE -> ESI_RESP
*/
static int
cnt_done(struct sess *sp, struct worker *wrk, struct req *req)
{
double dh, dp, da;
int i;
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
CHECK_OBJ_ORNULL(req->vcl, VCL_CONF_MAGIC);
AZ(req->obj);
AZ(req->busyobj);
req->director = NULL;
req->restarts = 0;
SES_Charge(sp);
/* If we did an ESI include, don't mess up our state */
if (req->esi_level > 0)
return (1);
if (req->vcl != NULL) {
if (wrk->vcl != NULL)
VCL_Rel(&wrk->vcl);
wrk->vcl = req->vcl;
req->vcl = NULL;
}
sp->t_idle = W_TIM_real(wrk);
if (req->xid == 0) {
req->t_resp = sp->t_idle;
} else {
dp = req->t_resp - req->t_req;
da = sp->t_idle - req->t_resp;
dh = req->t_req - sp->t_open;
/* XXX: Add StatReq == StatSess */
/* XXX: Workaround for pipe */
if (sp->fd >= 0) {
VSLb(req->vsl, SLT_Length, "%ju",
(uintmax_t)req->req_bodybytes);
}
VSLb(req->vsl, SLT_ReqEnd, "%u %.9f %.9f %.9f %.9f %.9f",
req->xid, req->t_req, sp->t_idle, dh, dp, da);
}
req->xid = 0;
VSL_Flush(req->vsl, 0);
req->t_req = NAN;
req->t_resp = NAN;
req->req_bodybytes = 0;
req->hash_always_miss = 0;
req->hash_ignore_busy = 0;
if (sp->fd >= 0 && req->doclose != NULL) {
/*
* This is an orderly close of the connection; ditch nolinger
* before we close, to get queued data transmitted.
*/
// XXX: not yet (void)VTCP_linger(sp->fd, 0);
SES_Close(sp, req->doclose);
}
if (sp->fd < 0) {
wrk->stats.sess_closed++;
SES_Delete(sp, NULL, NAN);
return (1);
}
if (wrk->stats.client_req >= cache_param->wthread_stats_rate)
WRK_SumStat(wrk);
WS_Reset(req->ws, NULL);
WS_Reset(wrk->aws, NULL);
i = HTC_Reinit(req->htc);
if (i == 1) {
req->t_req = sp->t_idle;
wrk->stats.sess_pipeline++;
sp->step = STP_START;
} else {
sp->t_rx = sp->t_idle;
req->t_req = NAN;
if (Tlen(req->htc->rxbuf))
wrk->stats.sess_readahead++;
sp->step = STP_WAIT;
}
return (0);
return (1);
}
/*--------------------------------------------------------------------
* Emit an error
*
......@@ -525,7 +595,7 @@ cnt_error(struct sess *sp, struct worker *wrk, struct req *req)
http_Teardown(bo->beresp);
http_Teardown(bo->bereq);
sp->step = STP_DONE;
return(0);
return(1);
}
CHECK_OBJ_NOTNULL(req->obj, OBJECT_MAGIC);
req->obj->xid = req->xid;
......@@ -1050,7 +1120,7 @@ cnt_lookup(struct sess *sp, struct worker *wrk, struct req *req)
* around to do the lookup with.
* NB: Do not access sp any more !
*/
return (1);
return (2);
}
AZ(req->objcore);
......@@ -1292,7 +1362,7 @@ cnt_pipe(struct sess *sp, struct worker *wrk, struct req *req)
http_Teardown(bo->bereq);
VBO_DerefBusyObj(wrk, &req->busyobj);
sp->step = STP_DONE;
return (0);
return (1);
}
/*--------------------------------------------------------------------
......@@ -1484,7 +1554,7 @@ cnt_start(struct sess *sp, struct worker *wrk, struct req *req)
if (req->err_code == 400) {
sp->step = STP_DONE;
SES_Close(sp, "junk");
return (0);
return (1);
}
req->ws_req = WS_Snapshot(req->ws);
......@@ -1501,7 +1571,7 @@ cnt_start(struct sess *sp, struct worker *wrk, struct req *req)
} else if (strlen(r) != write(sp->fd, r, strlen(r))) {
sp->step = STP_DONE;
SES_Close(sp, "remote closed");
return (0);
return (1);
}
}
http_Unset(req->http, H_Expect);
......@@ -1551,12 +1621,15 @@ cnt_diag(struct sess *sp, const char *state)
}
}
void
CNT_Session(struct sess *sp)
int
CNT_Request(struct req *req)
{
int done;
struct worker *wrk;
struct sess *sp;
CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
sp = req->sp;
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
wrk = sp->wrk;
CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
......@@ -1565,30 +1638,10 @@ CNT_Session(struct sess *sp)
* Possible entrance states
*/
assert(
sp->step == STP_WAIT ||
sp->step == STP_LOOKUP ||
sp->step == STP_START ||
sp->step == STP_RECV);
/*
* Whenever we come in from the acceptor or waiter, we need to set
* blocking mode, but there is no point in setting it when we come from
* ESI or when a parked sessions returns.
* It would be simpler to do this in the acceptor or waiter, but we'd
* rather do the syscall in the worker thread.
* On systems which return errors for ioctl, we close early
*/
if ((sp->step == STP_WAIT || sp->step == STP_START) &&
VTCP_blocking(sp->fd)) {
if (errno == ECONNRESET)
SES_Close(sp, "remote closed");
else
SES_Close(sp, "error");
sp->step = STP_DONE;
}
/*
* NB: Once done is set, we can no longer touch sp!
*/
for (done = 0; !done; ) {
assert(sp->wrk == wrk);
/*
......@@ -1599,12 +1652,12 @@ CNT_Session(struct sess *sp)
CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
CHECK_OBJ_ORNULL(wrk->nobjhead, OBJHEAD_MAGIC);
WS_Assert(wrk->aws);
CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
AN(req->sp);
assert(req->sp == sp);
if (sp->req != NULL) {
CHECK_OBJ_NOTNULL(sp->req, REQ_MAGIC);
AN(sp->req->sp);
assert(sp->req->sp == sp);
}
assert(sp->step != STP_WAIT);
assert(sp->step != STP_DONE);
switch (sp->step) {
#define SESS_STEP(l,u,arg) \
......@@ -1621,10 +1674,11 @@ CNT_Session(struct sess *sp)
WS_Assert(wrk->aws);
CHECK_OBJ_ORNULL(wrk->nobjhead, OBJHEAD_MAGIC);
}
#define ACCT(foo) AZ(wrk->acct_tmp.foo);
#include "tbl/acct_fields.h"
#undef ACCT
if (done == 1)
SES_Charge(sp);
assert(WRW_IsReleased(wrk));
return (done);
}
/*
......
bin/varnishd/cache/cache_esi_deliver.c
View file @ a1e3ed99
......@@ -49,6 +49,7 @@ ved_include(struct req *req, const char *src, const char *host)
char *sp_ws_wm;
char *wrk_ws_wm;
unsigned sxid, res_mode;
int i;
wrk = req->sp->wrk;
......@@ -94,9 +95,12 @@ ved_include(struct req *req, const char *src, const char *host)
sxid = req->xid;
while (1) {
req->sp->wrk = wrk;
CNT_Session(req->sp);
if (req->sp->step == STP_DONE)
i = CNT_Request(req);
if (req->sp->step == STP_DONE) {
assert(i == 1);
break;
}
assert(i == 2);
AZ(req->sp->wrk);
DSL(0x20, SLT_Debug, req->sp->vsl_id, "loop waiting for ESI");
(void)usleep(10000);
......
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