code review 9874055: runtime: use persistentalloc instead of custom malloc i...

runtime: use persistentalloc instead of custom malloc in memory profiler
Removes code duplication.

[dvyukov, 2013-06-09 17:22:36]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[bradfitz, 2013-06-09 17:23:52]

LGTM



On Sun, Jun 9, 2013 at 7:22 PM, <dvyukov@google.com> wrote:

> Reviewers: golang-dev1,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
>
https://dvyukov%40google.com@**code.google.com/p/go/<http://40google.com@code...
>
>
> Description:
> runtime: use persistentalloc instead of custom malloc in memory profiler
> Removes code duplication.
>
> Please review this at
https://codereview.appspot.**com/9874055/<https://codereview.appspot.com/9874...
>
> Affected files:
>   M src/pkg/runtime/mprof.goc
>
>
> Index: src/pkg/runtime/mprof.goc
> ==============================**==============================**=======
> --- a/src/pkg/runtime/mprof.goc
> +++ b/src/pkg/runtime/mprof.goc
> @@ -13,44 +13,11 @@
>  #include "type.h"
>
>  // NOTE(rsc): Everything here could use cas if contention became an issue.
> -static Lock proflock, alloclock;
> +static Lock proflock;
>
>  // All memory allocations are local and do not escape outside of the
> profiler.
>  // The profiler is forbidden from referring to garbage-collected memory.
>
> -static byte *pool;        // memory allocation pool
> -static uintptr poolfree;  // number of bytes left in the pool
> -enum {
> -       Chunk = 32*PageSize,  // initial size of the pool
> -};
> -
> -// Memory allocation local to this file.
> -// There is no way to return the allocated memory back to the OS.
> -static void*
> -allocate(uintptr size)
> -{
> -       void *v;
> -
> -       if(size == 0)
> -               return nil;
> -
> -       if(size >= Chunk/2)
> -               return runtime·SysAlloc(size);
> -
> -       runtime·lock(&alloclock);
> -       if(size > poolfree) {
> -               pool = runtime·SysAlloc(Chunk);
> -               if(pool == nil)
> -                       runtime·throw("runtime: cannot allocate memory");
> -               poolfree = Chunk;
> -       }
> -       v = pool;
> -       pool += size;
> -       poolfree -= size;
> -       runtime·unlock(&alloclock);
> -       return v;
> -}
> -
>  enum { MProf, BProf };  // profile types
>
>  // Per-call-stack profiling information.
> @@ -128,9 +95,7 @@
>         if(!alloc)
>                 return nil;
>
> -       b = allocate(sizeof *b + nstk*sizeof stk[0]);
> -       if(b == nil)
> -               runtime·throw("runtime: cannot allocate memory");
> +       b = runtime·persistentalloc(sizeof *b + nstk*sizeof stk[0], 0);
>         bucketmem += sizeof *b + nstk*sizeof stk[0];
>         runtime·memmove(b->stk, stk, nstk*sizeof stk[0]);
>         b->typ = typ;
> @@ -232,7 +197,7 @@
>                 if(ah->addr == (addr>>AddrHashShift))
>                         goto found;
>
> -       ah = allocate(sizeof *ah);
> +       ah = runtime·persistentalloc(sizeof *ah, 0);
>         addrmem += sizeof *ah;
>         ah->next = addrhash[h];
>         ah->addr = addr>>AddrHashShift;
> @@ -240,7 +205,7 @@
>
>  found:
>         if((e = addrfree) == nil) {
> -               e = allocate(64*sizeof *e);
> +               e = runtime·persistentalloc(64***sizeof *e, 0);
>                 addrmem += 64*sizeof *e;
>                 for(i=0; i+1<64; i++)
>                         e[i].next = &e[i+1];
> @@ -554,5 +519,5 @@
>  void
>  runtime·mprofinit(void)
>  {
> -       addrhash = allocate((1<<AddrHashBits)***sizeof *addrhash);
> +       addrhash = runtime·persistentalloc((1<<**AddrHashBits)*sizeof
> *addrhash, 0);
>  }
>
>
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>

[dvyukov, 2013-06-09 17:38:55]

*** Submitted as https://code.google.com/p/go/source/detail?r=6f3e6d2e7f1c ***

runtime: use persistentalloc instead of custom malloc in memory profiler
Removes code duplication.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/9874055