undo CL 9805043 / 776aba85ece8

multiple failures on amd64

««« original CL description
runtime: introduce helper persistentalloc() function
It is a caching wrapper around SysAlloc() that can allocate small chunks.
Use it for symtab allocations. Reduces number of symtab walks from 4 to 3
(reduces buildfuncs time from 10ms to 7.5ms on a large binary,
reduces initial heap size by 680K on the same binary).
Also can be used for type info allocation, itab allocation.
There are also several places in GC where we do the same thing,
they can be changed to use persistentalloc().
Also can be used in FixAlloc, because each instance of FixAlloc allocates
in 128K regions, which is too eager.

R=golang-dev, daniel.morsing, khr
CC=golang-dev
https://golang.org/cl/9805043
»»»

R=golang-dev
CC=golang-dev
https://golang.org/cl/9822043

diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index 47eb005894f910f9b7019f2fe0a07702b4586eb0..516182c1cf0543eacf74fb44b48110cd1e9ae377 100644 (file)
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -496,53 +496,6 @@ runtime·MHeap_SysAlloc(MHeap *h, uintptr n)
        return p;
 }
 
-static struct
-{
-       Lock;
-       byte*   pos;
-       byte*   end;
-} persistent;
-
-enum
-{
-       PersistentAllocChunk    = 256<<10,
-       PersistentAllocMaxBlock = 64<<10,  // VM reservation granularity is 64K on windows
-};
-
-// Wrapper around SysAlloc that can allocate small chunks.
-// There is no associated free operation.
-// Intended for things like function/type/debug-related persistent data.
-// If align is 0, uses default align (currently 8).
-void*
-runtime·persistentalloc(uintptr size, uintptr align)
-{
-       byte *p;
-
-       if(align) {
-               if(align&(align-1))
-                       runtime·throw("persistentalloc: align is now a power of 2");
-               if(align > PageSize)
-                       runtime·throw("persistentalloc: align is too large");
-       } else
-               align = 8;
-       if(size >= PersistentAllocMaxBlock)
-               return runtime·SysAlloc(size);
-       runtime·lock(&persistent);
-       persistent.pos = (byte*)ROUND((uintptr)persistent.pos, align);
-       if(persistent.pos + size > persistent.end) {
-               persistent.pos = runtime·SysAlloc(PersistentAllocChunk);
-               if(persistent.pos == nil) {
-                       runtime·unlock(&persistent);
-                       runtime·throw("runtime: cannot allocate memory");
-               }
-               persistent.end = persistent.pos + PersistentAllocChunk;
-       }
-       p = persistent.pos;
-       persistent.pos += size;
-       runtime·unlock(&persistent);
-       return p; 
-}
-
 static Lock settype_lock;
 
 void

diff --git a/src/pkg/runtime/malloc.h b/src/pkg/runtime/malloc.h
index 1085344ee1f83f0cd8ba18897b57e553b1d0c3c6..b4edf7cbef0b4db2df906923ba9fad695e7e91c3 100644 (file)
--- a/src/pkg/runtime/malloc.h
+++ b/src/pkg/runtime/malloc.h
@@ -445,7 +445,6 @@ void        runtime·MHeap_MapBits(MHeap *h);
 void   runtime·MHeap_Scavenger(void);
 
 void*  runtime·mallocgc(uintptr size, uint32 flag, int32 dogc, int32 zeroed);
-void*  runtime·persistentalloc(uintptr size, uintptr align);
 int32  runtime·mlookup(void *v, byte **base, uintptr *size, MSpan **s);
 void   runtime·gc(int32 force);
 void   runtime·markallocated(void *v, uintptr n, bool noptr);

diff --git a/src/pkg/runtime/symtab.c b/src/pkg/runtime/symtab.c
index fdebe2cae374e72507858622f200f2483438dc4d..5edcb49bda8c5ed35affbb31264874099bd7a630 100644 (file)
--- a/src/pkg/runtime/symtab.c
+++ b/src/pkg/runtime/symtab.c
@@ -69,6 +69,11 @@ struct Sym
 
 static uintptr mainoffset;
 
+// A dynamically allocated string containing multiple substrings.
+// Individual strings are slices of hugestring.
+static String hugestring;
+static int32 hugestring_len;
+
 extern void main·main(void);
 
 static uintptr
@@ -283,6 +288,7 @@ makepath(byte *buf, int32 nbuf, byte *path)
        return p - buf;
 }
 
+// appends p to hugestring
 static String
 gostringn(byte *p, int32 l)
 {
@@ -290,8 +296,13 @@ gostringn(byte *p, int32 l)
 
        if(l == 0)
                return runtime·emptystring;
+       if(hugestring.str == nil) {
+               hugestring_len += l;
+               return runtime·emptystring;
+       }
+       s.str = hugestring.str + hugestring.len;
        s.len = l;
-       s.str = runtime·persistentalloc(l, 1);
+       hugestring.len += s.len;
        runtime·memmove(s.str, p, l);
        return s;
 }
@@ -322,6 +333,8 @@ dosrcline(Sym *sym)
        switch(sym->symtype) {
        case 't':
        case 'T':
+               if(hugestring.str == nil)
+                       break;
                if(runtime·strcmp(sym->name, (byte*)"etext") == 0)
                        break;
                f = &func[nfunc++];
@@ -546,12 +559,11 @@ buildfuncs(void)
        walksymtab(dofunc);
 
        // Initialize tables.
-       // Memory obtained from runtime·persistentalloc() is not scanned by GC,
-       // this is fine because all pointers either point into sections of the executable
-       // or also obtained from persistentmalloc().
-       func = runtime·persistentalloc((nfunc+1)*sizeof func[0], 0);
+       // Can use FlagNoPointers - all pointers either point into sections of the executable
+       // or point into hugestring.
+       func = runtime·mallocgc((nfunc+1)*sizeof func[0], FlagNoPointers, 0, 1);
        func[nfunc].entry = (uint64)etext;
-       fname = runtime·persistentalloc(nfname*sizeof fname[0], 0);
+       fname = runtime·mallocgc(nfname*sizeof fname[0], FlagNoPointers, 0, 1);
        nfunc = 0;
        lastvalue = 0;
        walksymtab(dofunc);
@@ -561,9 +573,15 @@ buildfuncs(void)
 
        // record src file and line info for each func
        files = runtime·malloc(maxfiles * sizeof(files[0]));
-       walksymtab(dosrcline);
+       walksymtab(dosrcline);  // pass 1: determine hugestring_len
+       hugestring.str = runtime·mallocgc(hugestring_len, FlagNoPointers, 0, 0);
+       hugestring.len = 0;
+       walksymtab(dosrcline);  // pass 2: fill and use hugestring
        files = nil;
 
+       if(hugestring.len != hugestring_len)
+               runtime·throw("buildfunc: problem in initialization procedure");
+
        m->nomemprof--;
 }