Changeset 4100

Timestamp:

06/09/09 12:41:38 (15 months ago)

Author:

phk

Message:

Remove the vcl_timeout{} VCL callback.

We had big plans for this originally, but none of them have materialized
because there are better ways to do those things.

For instance: why invent a lot of code to do prefetch, when wget(1) can
do the job already ?

Getting rid of vcl_timeout{} (and vcl_discard{}, see yesterdays commit)
simplifies the expiry codes locking and statekeeping significantly.

Location:

trunk/varnish-cache

Files:

• bin/varnishd/cache_expire.c (modified) (8 diffs)
• bin/varnishd/default.vcl (modified) (1 diff)
• include/vcl.h (modified) (2 diffs)
• include/vcl_returns.h (modified) (1 diff)
• lib/libvcl/vcc_fixed_token.c (modified) (4 diffs)
• lib/libvcl/vcc_gen_fixed_token.tcl (modified) (1 diff)
• lib/libvcl/vcc_gen_obj.tcl (modified) (2 diffs)
• lib/libvcl/vcc_obj.c (modified) (4 diffs)
• man/vcl.7so (modified) (1 diff)

trunk/varnish-cache/bin/varnishd/cache_expire.c

@@ -32 +32 @@
  * and two ways to kill objects: TTL-timeouts and LRU cleanups.
  *
- * To avoid holding the mutex while we ponder the fate of objects, we
- * have the following prototol:
- *
- * Any object on the LRU is also on the binheap (normal case)
- *
- * An object is taken off only the binheap but left on the LRU during timer
- * processing because we have no easy way to put it back the right place
- * in the LRU list.
- *
- * An object is taken off both LRU and binheap for LRU processing, (which
- * implies that it must be on both, from where it follows that the timer
- * is not chewing on it) because we expect the majority of objects to be
- * discarded by LRU and save a lock cycle that way, and because we can
- * properly replace it's position in the binheap.
+ * Any object on the LRU is also on the binheap and vice versa.
+ *
+ * We hold one object reference for both data structures.
+ *
  */
 
@@ -113 +103 @@
 
         CHECK_OBJ_NOTNULL(o, OBJECT_MAGIC);
+        AN(o->objhead);
         AN(ObjIsBusy(o));
         assert(o->cacheable);
@@ -152 +143 @@
         if (oc == NULL)
                 return (retval);
+        AN(o->objhead);
         CHECK_OBJ_NOTNULL(oc, OBJCORE_MAGIC);
         if (Lck_Trylock(&exp_mtx))
@@ -242 +234 @@
                 CHECK_OBJ_NOTNULL(o, OBJECT_MAGIC);
                 CHECK_OBJ_NOTNULL(o->objhead, OBJHEAD_MAGIC);
+                assert(oc->flags & OC_F_ONLRU);
                 assert(oc->timer_idx != BINHEAP_NOIDX);
                 binheap_delete(exp_heap, oc->timer_idx);
                 assert(oc->timer_idx == BINHEAP_NOIDX);
+                VTAILQ_REMOVE(&lru, o->objcore, lru_list);
+                oc->flags &= ~OC_F_ONLRU;
 
                 {       /* Sanity checking */
@@ -254 +249 @@
                 }
 
-                assert(oc->flags & OC_F_ONLRU);
-                Lck_Unlock(&exp_mtx);
-
-                WSL(sp->wrk, SLT_ExpPick, 0, "%u TTL", o->xid);
-
-                sp->obj = o;
-                VCL_timeout_method(sp);
-                sp->obj = NULL;
-
-                assert(sp->handling == VCL_RET_DISCARD);
-                WSL(sp->wrk, SLT_ExpKill, 0,
-                    "%u %d", o->xid, (int)(o->ttl - t));
-                Lck_Lock(&exp_mtx);
-                assert(oc->timer_idx == BINHEAP_NOIDX);
-                assert(oc->flags & OC_F_ONLRU);
-                VTAILQ_REMOVE(&lru, o->objcore, lru_list);
-                oc->flags &= ~OC_F_ONLRU;
                 VSL_stats->n_expired++;
                 Lck_Unlock(&exp_mtx);
+                WSL(sp->wrk, SLT_ExpKill, 0, "%u %d",
+                    o->xid, (int)(o->ttl - t));
                 HSH_Deref(sp->wrk, &o);
         }
@@ -278 +258 @@
 
 /*--------------------------------------------------------------------
- * Attempt to make space by nuking, with VCLs permission, the oldest
- * object on the LRU list which isn't in use.
+ * Attempt to make space by nuking, the oldest object on the LRU list
+ * which isn't in use.
  * Returns: 1: did, 0: didn't, -1: can't
  */
@@ -292 +272 @@
          * Find the first currently unused object on the LRU.
          *
-         * Ideally we would have the refcnt in the objcore so we the object does
+         * Ideally we would have the refcnt in the objcore so we object does
          * not need to get paged in for this check, but it does not pay off
          * the complexity:  The chances of an object being in front of the LRU,
@@ -298 +278 @@
          * object with no active references will be prodded further anyway.
          *
-         * NB: Checking refcount here is no guarantee that it does not gain
-         * another ref while we ponder its destiny without the lock held.
          */
         Lck_Lock(&exp_mtx);

trunk/varnish-cache/bin/varnishd/default.vcl

@@ -111 +111 @@
 }
 
-sub vcl_timeout {
-    /* XXX: Do not redefine vcl_timeout{}, it is not yet supported */
-    return (discard);
-}
-
 sub vcl_error {
     set obj.http.Content-Type = "text/html; charset=utf-8";

trunk/varnish-cache/include/vcl.h

@@ -23 +23 @@
 #define VCL_MET_FETCH           (1 << 6)
 #define VCL_MET_DELIVER         (1 << 7)
-#define VCL_MET_TIMEOUT         (1 << 8)
-#define VCL_MET_ERROR           (1 << 9)
+#define VCL_MET_ERROR           (1 << 8)
 
-#define VCL_MET_MAX             10
+#define VCL_MET_MAX             9
 
 /* VCL Returns */
@@ -70 +69 @@
         vcl_func_f      *fetch_func;
         vcl_func_f      *deliver_func;
-        vcl_func_f      *timeout_func;
         vcl_func_f      *error_func;
 };

trunk/varnish-cache/include/vcl_returns.h

@@ -61 +61 @@
     | (1 << VCL_RET_DELIVER)
 ))
-VCL_MET_MAC(timeout,TIMEOUT,
-     ((1 << VCL_RET_FETCH)
-    | (1 << VCL_RET_DISCARD)
-))
 VCL_MET_MAC(error,ERROR,
      ((1 << VCL_RET_RESTART)

trunk/varnish-cache/lib/libvcl/vcc_fixed_token.c

@@ -1 +1 @@
 /*
- * $Id: vcc_gen_fixed_token.tcl 3948 2009-03-18 11:25:43Z kristian $
+ * $Id: vcc_gen_fixed_token.tcl 4099 2009-06-08 21:40:48Z phk $
  *
  * NB:  This file is machine generated, DO NOT EDIT!
@@ -160 +160 @@
         /* ../../include/vcl.h */
 
-        vsb_cat(sb, "/*\n * $Id: vcc_gen_fixed_token.tcl 3948 2009-03-18 11");
-        vsb_cat(sb, ":25:43Z kristian $\n *\n * NB:  This file is machine g");
-        vsb_cat(sb, "enerated, DO NOT EDIT!\n *\n * Edit and run vcc_gen_fi");
-        vsb_cat(sb, "xed_token.tcl instead\n */\n\nstruct sess;\n");
+        vsb_cat(sb, "/*\n * $Id: vcc_gen_fixed_token.tcl 4099 2009-06-08 21");
+        vsb_cat(sb, ":40:48Z phk $\n *\n * NB:  This file is machine genera");
+        vsb_cat(sb, "ted, DO NOT EDIT!\n *\n * Edit and run vcc_gen_fixed_t");
+        vsb_cat(sb, "oken.tcl instead\n */\n\nstruct sess;\n");
         vsb_cat(sb, "struct cli;\n\ntypedef void vcl_init_f(struct cli *);\n");
         vsb_cat(sb, "typedef void vcl_fini_f(struct cli *);\n");
@@ -175 +175 @@
         vsb_cat(sb, "#define VCL_MET_FETCH\t\t(1 << 6)\n");
         vsb_cat(sb, "#define VCL_MET_DELIVER\t\t(1 << 7)\n");
-        vsb_cat(sb, "#define VCL_MET_TIMEOUT\t\t(1 << 8)\n");
-        vsb_cat(sb, "#define VCL_MET_ERROR\t\t(1 << 9)\n");
-        vsb_cat(sb, "\n#define VCL_MET_MAX\t\t10\n\n");
-        vsb_cat(sb, "/* VCL Returns */\n#define VCL_RET_ERROR\t\t0\n");
-        vsb_cat(sb, "#define VCL_RET_LOOKUP\t\t1\n#define VCL_RET_HASH\t\t2");
-        vsb_cat(sb, "\n#define VCL_RET_PIPE\t\t3\n#define VCL_RET_PASS\t\t4");
-        vsb_cat(sb, "\n#define VCL_RET_FETCH\t\t5\n#define VCL_RET_DELIVER\t");
-        vsb_cat(sb, "\t6\n#define VCL_RET_DISCARD\t\t7\n");
-        vsb_cat(sb, "#define VCL_RET_KEEP\t\t8\n#define VCL_RET_RESTART\t\t");
-        vsb_cat(sb, "9\n\n#define VCL_RET_MAX\t\t10\n");
-        vsb_cat(sb, "\nstruct VCL_conf {\n\tunsigned\tmagic;\n");
+        vsb_cat(sb, "#define VCL_MET_ERROR\t\t(1 << 8)\n");
+        vsb_cat(sb, "\n#define VCL_MET_MAX\t\t9\n\n/* VCL Returns */\n");
+        vsb_cat(sb, "#define VCL_RET_ERROR\t\t0\n#define VCL_RET_LOOKUP\t\t");
+        vsb_cat(sb, "1\n#define VCL_RET_HASH\t\t2\n#define VCL_RET_PIPE\t\t");
+        vsb_cat(sb, "3\n#define VCL_RET_PASS\t\t4\n#define VCL_RET_FETCH\t\t");
+        vsb_cat(sb, "5\n#define VCL_RET_DELIVER\t\t6\n");
+        vsb_cat(sb, "#define VCL_RET_DISCARD\t\t7\n#define VCL_RET_KEEP\t\t");
+        vsb_cat(sb, "8\n#define VCL_RET_RESTART\t\t9\n");
+        vsb_cat(sb, "\n#define VCL_RET_MAX\t\t10\n\n");
+        vsb_cat(sb, "struct VCL_conf {\n\tunsigned\tmagic;\n");
         vsb_cat(sb, "#define VCL_CONF_MAGIC\t0x7406c509\t/* from /dev/rando");
         vsb_cat(sb, "m */\n\n\tstruct director\t**director;\n");
@@ -198 +197 @@
         vsb_cat(sb, "\tvcl_func_f\t*miss_func;\n\tvcl_func_f\t*hit_func;\n");
         vsb_cat(sb, "\tvcl_func_f\t*fetch_func;\n\tvcl_func_f\t*deliver_fun");
-        vsb_cat(sb, "c;\n\tvcl_func_f\t*timeout_func;\n");
-        vsb_cat(sb, "\tvcl_func_f\t*error_func;\n};\n");
+        vsb_cat(sb, "c;\n\tvcl_func_f\t*error_func;\n");
+        vsb_cat(sb, "};\n");
 
         /* ../../include/vrt.h */

trunk/varnish-cache/lib/libvcl/vcc_gen_fixed_token.tcl

@@ -43 +43 @@
         {fetch          {error restart pass deliver}}
         {deliver        {restart deliver}}
-        {timeout        {fetch discard}}
         {error          {restart deliver}}
 }

trunk/varnish-cache/lib/libvcl/vcc_gen_obj.tcl

@@ -234 +234 @@
     { obj.ttl
         RW TIME
-        {                         hit               timeout error}
+        {                         hit               error}
         "const struct sess *"
     }
     { obj.grace
         RW TIME
-        {                         hit               timeout error}
+        {                         hit               error}
         "const struct sess *"
     }
     { obj.lastuse
         RO TIME
-        {                         hit       deliver timeout error}
+        {                         hit       deliver error}
         "const struct sess *"
     }
@@ -281 +281 @@
     { now
             RO TIME
-            {recv pipe pass hash miss hit fetch deliver timeout}
+            {recv pipe pass hash miss hit fetch deliver }
             "const struct sess *"
     }
     { req.backend.healthy       RO BOOL
-            {recv pipe pass hash miss hit fetch deliver timeout}
+            {recv pipe pass hash miss hit fetch deliver }
             "const struct sess *"
     }

trunk/varnish-cache/lib/libvcl/vcc_obj.c

@@ -1 +1 @@
 /*
- * $Id: vcc_gen_obj.tcl 4066 2009-05-10 21:21:36Z sky $
+ * $Id: vcc_gen_obj.tcl 4099 2009-06-08 21:40:48Z phk $
  *
  * NB:  This file is machine generated, DO NOT EDIT!
@@ -216 +216 @@
             "VRT_r_obj_ttl(sp)",            "VRT_l_obj_ttl(sp, ",
             V_RW,           0,
-            VCL_MET_HIT | VCL_MET_TIMEOUT | VCL_MET_ERROR
+            VCL_MET_HIT | VCL_MET_ERROR
         },
         { "obj.grace", TIME, 9,
             "VRT_r_obj_grace(sp)",          "VRT_l_obj_grace(sp, ",
             V_RW,           0,
-            VCL_MET_HIT | VCL_MET_TIMEOUT | VCL_MET_ERROR
+            VCL_MET_HIT | VCL_MET_ERROR
         },
         { "obj.lastuse", TIME, 11,
             "VRT_r_obj_lastuse(sp)",        NULL,
             V_RO,           0,
-            VCL_MET_HIT | VCL_MET_DELIVER | VCL_MET_TIMEOUT | VCL_MET_ERROR
+            VCL_MET_HIT | VCL_MET_DELIVER | VCL_MET_ERROR
         },
         { "obj.hash", STRING, 8,
@@ -258 +258 @@
             VCL_MET_RECV | VCL_MET_PIPE | VCL_MET_PASS | VCL_MET_HASH
              | VCL_MET_MISS | VCL_MET_HIT | VCL_MET_FETCH | VCL_MET_DELIVER
-             | VCL_MET_TIMEOUT
         },
         { "req.backend.healthy", BOOL, 19,
@@ -265 +264 @@
             VCL_MET_RECV | VCL_MET_PIPE | VCL_MET_PASS | VCL_MET_HASH
              | VCL_MET_MISS | VCL_MET_HIT | VCL_MET_FETCH | VCL_MET_DELIVER
-             | VCL_MET_TIMEOUT
         },
         { NULL }

trunk/varnish-cache/man/vcl.7so

@@ -445 +445 @@
 Deliver the object to the client.
 .El
-.\" vcl_timeout
-.It Cm vcl_timeout
-Called by the reaper thread shortly before a cached document reaches
-its expiry time.
-.Pp
-The
-.Cm vcl_timeout
-subroutine may terminate with one of the following keywords:
-.Bl -tag -width indent
-.It Cm fetch
-Request a fresh copy of the object from the backend.
-.It Cm discard
-Discard the object.
-.El
-.\" vcl_discard
-.It Cm vcl_discard
-Called by the reaper thread when a cached document is about to be
-discarded, either because it has expired or because space is running
-low.
-.Pp
-The
-.Cm vcl_discard
-subroutine may terminate with one of the following keywords:
-.Bl -tag -width indent
-.It Cm discard
-Discard the object.
-.It Cm keep
-Keep the object in cache.
-.El
 .El
 .Pp