code review 56060043: undo CL 45770044 / d795425bfa18

src/pkg/runtime/netpoll.goc

 // Copyright 2013 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // +build darwin dragonfly freebsd linux netbsd openbsd solaris windows
 
 package net
 
 #include "runtime.h"
 #include "defs_GOOS_GOARCH.h"
@@ skipping 16 matching lines @@
 //        the goroutine commits to park by changing the state to G pointer,
 //        or, alternatively, concurrent io notification changes the state to READY,
 //        or, alternatively, concurrent timeout/close changes the state to nil.
 // G pointer - the goroutine is blocked on the semaphore;
 //             io notification or timeout/close changes the state to READY or nil respectively
 //             and unparks the goroutine.
 // nil - nothing of the above.
 #define READY ((G*)1)
 #define WAIT  ((G*)2)
 
-enum
-{
-        PollBlockSize   = 4*1024,
-};
-
 struct PollDesc
 {
         PollDesc* link; // in pollcache, protected by pollcache.Lock
 
         // The lock protects pollOpen, pollSetDeadline, pollUnblock and deadlineimpl operations.
         // This fully covers seq, rt and wt variables. fd is constant throughout the PollDesc lifetime.
         // pollReset, pollWait, pollWaitCanceled and runtime·netpollready (IO rediness notification)
         // proceed w/o taking the lock. So closing, rg, rd, wg and wd are manipulated
         // in a lock-free way by all operations.
         Lock;           // protectes the following fields
@@ skipping 368 matching lines @@
 }
 
 static PollDesc*
 allocPollDesc(void)
 {
         PollDesc *pd;
         uint32 i, n;
 
         runtime·lock(&pollcache);
         if(pollcache.first == nil) {
-                n = PollBlockSize/sizeof(*pd);
+                n = PageSize/sizeof(*pd);
                 if(n == 0)
                         n = 1;
                 // Must be in non-GC memory because can be referenced
                 // only from epoll/kqueue internals.
                 pd = runtime·persistentalloc(n*sizeof(*pd), 0, &mstats.other_sys);
                 for(i = 0; i < n; i++) {
                         pd[i].link = pollcache.first;
                         pollcache.first = &pd[i];
                 }
         }
         pd = pollcache.first;
         pollcache.first = pd->link;
         runtime·unlock(&pollcache);
         return pd;
 }