Commit 016bac72 authored by Simon Marlow's avatar Simon Marlow
Browse files

Refactoring: extract platform-specific code from sm/MBlock.c

Also common-up some duplicate bits in the platform-specific code
parent c408face
/* -----------------------------------------------------------------------------
*
* (c) The University of Glasgow 2006
* (c) The University of Glasgow 2006-2007
*
* OS-specific memory management
*
* ---------------------------------------------------------------------------*/
/* This is non-posix compliant. */
/* #include "PosixSource.h" */
#include "Rts.h"
#include "OSMem.h"
#include "RtsFlags.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <errno.h>
#if darwin_HOST_OS
#include <mach/mach.h>
#include <mach/vm_map.h>
#endif
static caddr_t next_request = 0;
void osMemInit(void)
{
next_request = (caddr_t)RtsFlags.GcFlags.heapBase;
}
/* -----------------------------------------------------------------------------
The mmap() method
On Unix-like systems, we use mmap() to allocate our memory. We
want memory in chunks of MBLOCK_SIZE, and aligned on an MBLOCK_SIZE
boundary. The mmap() interface doesn't give us this level of
control, so we have to use some heuristics.
In the general case, if we want a block of n megablocks, then we
allocate n+1 and trim off the slop from either side (using
munmap()) to get an aligned chunk of size n. However, the next
time we'll try to allocate directly after the previously allocated
chunk, on the grounds that this is aligned and likely to be free.
If it turns out that we were wrong, we have to munmap() and try
again using the general method.
Note on posix_memalign(): this interface is available on recent
systems and appears to provide exactly what we want. However, it
turns out not to be as good as our mmap() implementation, because
it wastes extra space (using double the address space, in a test on
x86_64/Linux). The problem seems to be that posix_memalign()
returns memory that can be free()'d, so the library must store
extra information along with the allocated block, thus messing up
the alignment. Hence, we don't use posix_memalign() for now.
-------------------------------------------------------------------------- */
// A wrapper around mmap(), to abstract away from OS differences in
// the mmap() interface.
static void *
my_mmap (void *addr, lnat size)
{
void *ret;
#if defined(solaris2_HOST_OS) || defined(irix_HOST_OS)
{
int fd = open("/dev/zero",O_RDONLY);
ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
close(fd);
}
#elif hpux_HOST_OS
ret = mmap(addr, size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
#elif darwin_HOST_OS
// Without MAP_FIXED, Apple's mmap ignores addr.
// With MAP_FIXED, it overwrites already mapped regions, whic
// mmap(0, ... MAP_FIXED ...) is worst of all: It unmaps the program text
// and replaces it with zeroes, causing instant death.
// This behaviour seems to be conformant with IEEE Std 1003.1-2001.
// Let's just use the underlying Mach Microkernel calls directly,
// they're much nicer.
kern_return_t err;
ret = addr;
if(addr) // try to allocate at adress
err = vm_allocate(mach_task_self(),(vm_address_t*) &ret, size, FALSE);
if(!addr || err) // try to allocate anywhere
err = vm_allocate(mach_task_self(),(vm_address_t*) &ret, size, TRUE);
if(err) {
// don't know what the error codes mean exactly, assume it's
// not our problem though.
errorBelch("memory allocation failed (requested %lu bytes)", size);
stg_exit(EXIT_FAILURE);
} else {
vm_protect(mach_task_self(),(vm_address_t)ret,size,FALSE,VM_PROT_READ|VM_PROT_WRITE);
}
#else
ret = mmap(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANON | MAP_PRIVATE, -1, 0);
#endif
if (ret == (void *)-1) {
if (errno == ENOMEM ||
(errno == EINVAL && sizeof(void*)==4 && size >= 0xc0000000)) {
// If we request more than 3Gig, then we get EINVAL
// instead of ENOMEM (at least on Linux).
errorBelch("out of memory (requested %lu bytes)", size);
stg_exit(EXIT_FAILURE);
} else {
barf("getMBlock: mmap: %s", strerror(errno));
}
}
return ret;
}
// Implements the general case: allocate a chunk of memory of 'size'
// mblocks.
static void *
gen_map_mblocks (lnat size)
{
int slop;
void *ret;
// Try to map a larger block, and take the aligned portion from
// it (unmap the rest).
size += MBLOCK_SIZE;
ret = my_mmap(0, size);
// unmap the slop bits around the chunk we allocated
slop = (W_)ret & MBLOCK_MASK;
if (munmap(ret, MBLOCK_SIZE - slop) == -1) {
barf("gen_map_mblocks: munmap failed");
}
if (slop > 0 && munmap(ret+size-slop, slop) == -1) {
barf("gen_map_mblocks: munmap failed");
}
// ToDo: if we happened to get an aligned block, then don't
// unmap the excess, just use it. For this to work, you
// need to keep in mind the following:
// * Calling my_mmap() with an 'addr' arg pointing to
// already my_mmap()ed space is OK and won't fail.
// * If my_mmap() can't satisfy the request at the
// given 'next_request' address in getMBlocks(), that
// you unmap the extra mblock mmap()ed here (or simply
// satisfy yourself that the slop introduced isn't worth
// salvaging.)
//
// next time, try after the block we just got.
ret += MBLOCK_SIZE - slop;
return ret;
}
void *
osGetMBlocks(nat n)
{
caddr_t ret;
lnat size = MBLOCK_SIZE * n;
if (next_request == 0) {
// use gen_map_mblocks the first time.
ret = gen_map_mblocks(size);
} else {
ret = my_mmap(next_request, size);
if (((W_)ret & MBLOCK_MASK) != 0) {
// misaligned block!
#if 0 // defined(DEBUG)
errorBelch("warning: getMBlock: misaligned block %p returned when allocating %d megablock(s) at %p", ret, n, next_request);
#endif
// unmap this block...
if (munmap(ret, size) == -1) {
barf("getMBlock: munmap failed");
}
// and do it the hard way
ret = gen_map_mblocks(size);
}
}
// Next time, we'll try to allocate right after the block we just got.
// ToDo: check that we haven't already grabbed the memory at next_request
next_request = ret + size;
return ret;
}
void osFreeAllMBlocks(void)
{
/* XXX Do something here (bug #711) */
}
lnat getPageSize (void)
{
......
/* -----------------------------------------------------------------------------
*
* (c) The GHC Team 1998-1999
* (c) The GHC Team 1998-2007
*
* MegaBlock Allocator Interface. This file contains all the dirty
* architecture-dependent hackery required to get a chunk of aligned
......@@ -8,58 +8,21 @@
*
* ---------------------------------------------------------------------------*/
/* This is non-posix compliant. */
/* #include "PosixSource.h" */
#include "PosixSource.h"
#include "Rts.h"
#include "RtsUtils.h"
#include "RtsFlags.h"
#include "MBlock.h"
#include "BlockAlloc.h"
#include "Trace.h"
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifndef mingw32_HOST_OS
# ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
# endif
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_WINDOWS_H
#include <windows.h>
#endif
#if darwin_HOST_OS
#include <mach/mach.h>
#include <mach/vm_map.h>
#endif
#include <errno.h>
#include "OSMem.h"
lnat mblocks_allocated = 0;
#if !defined(mingw32_HOST_OS) && !defined(cygwin32_HOST_OS)
static caddr_t next_request = 0;
#endif
void
initMBlocks(void)
{
#if !defined(mingw32_HOST_OS) && !defined(cygwin32_HOST_OS)
next_request = (caddr_t)RtsFlags.GcFlags.heapBase;
#endif
osMemInit();
}
/* -----------------------------------------------------------------------------
......@@ -133,379 +96,25 @@ getMBlock(void)
return getMBlocks(1);
}
/* -----------------------------------------------------------------------------
The mmap() method
On Unix-like systems, we use mmap() to allocate our memory. We
want memory in chunks of MBLOCK_SIZE, and aligned on an MBLOCK_SIZE
boundary. The mmap() interface doesn't give us this level of
control, so we have to use some heuristics.
In the general case, if we want a block of n megablocks, then we
allocate n+1 and trim off the slop from either side (using
munmap()) to get an aligned chunk of size n. However, the next
time we'll try to allocate directly after the previously allocated
chunk, on the grounds that this is aligned and likely to be free.
If it turns out that we were wrong, we have to munmap() and try
again using the general method.
Note on posix_memalign(): this interface is available on recent
systems and appears to provide exactly what we want. However, it
turns out not to be as good as our mmap() implementation, because
it wastes extra space (using double the address space, in a test on
x86_64/Linux). The problem seems to be that posix_memalign()
returns memory that can be free()'d, so the library must store
extra information along with the allocated block, thus messing up
the alignment. Hence, we don't use posix_memalign() for now.
-------------------------------------------------------------------------- */
#if !defined(mingw32_HOST_OS) && !defined(cygwin32_HOST_OS)
// A wrapper around mmap(), to abstract away from OS differences in
// the mmap() interface.
static void *
my_mmap (void *addr, lnat size)
{
void *ret;
#if defined(solaris2_HOST_OS) || defined(irix_HOST_OS)
{
int fd = open("/dev/zero",O_RDONLY);
ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
close(fd);
}
#elif hpux_HOST_OS
ret = mmap(addr, size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
#elif darwin_HOST_OS
// Without MAP_FIXED, Apple's mmap ignores addr.
// With MAP_FIXED, it overwrites already mapped regions, whic
// mmap(0, ... MAP_FIXED ...) is worst of all: It unmaps the program text
// and replaces it with zeroes, causing instant death.
// This behaviour seems to be conformant with IEEE Std 1003.1-2001.
// Let's just use the underlying Mach Microkernel calls directly,
// they're much nicer.
kern_return_t err;
ret = addr;
if(addr) // try to allocate at adress
err = vm_allocate(mach_task_self(),(vm_address_t*) &ret, size, FALSE);
if(!addr || err) // try to allocate anywhere
err = vm_allocate(mach_task_self(),(vm_address_t*) &ret, size, TRUE);
if(err) {
// don't know what the error codes mean exactly, assume it's
// not our problem though.
errorBelch("memory allocation failed (requested %lu bytes)", size);
stg_exit(EXIT_FAILURE);
} else {
vm_protect(mach_task_self(),(vm_address_t)ret,size,FALSE,VM_PROT_READ|VM_PROT_WRITE);
}
#else
ret = mmap(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANON | MAP_PRIVATE, -1, 0);
#endif
if (ret == (void *)-1) {
if (errno == ENOMEM ||
(errno == EINVAL && sizeof(void*)==4 && size >= 0xc0000000)) {
// If we request more than 3Gig, then we get EINVAL
// instead of ENOMEM (at least on Linux).
errorBelch("out of memory (requested %lu bytes)", size);
stg_exit(EXIT_FAILURE);
} else {
barf("getMBlock: mmap: %s", strerror(errno));
}
}
return ret;
}
// Implements the general case: allocate a chunk of memory of 'size'
// mblocks.
static void *
gen_map_mblocks (lnat size)
{
int slop;
void *ret;
// Try to map a larger block, and take the aligned portion from
// it (unmap the rest).
size += MBLOCK_SIZE;
ret = my_mmap(0, size);
// unmap the slop bits around the chunk we allocated
slop = (W_)ret & MBLOCK_MASK;
if (munmap(ret, MBLOCK_SIZE - slop) == -1) {
barf("gen_map_mblocks: munmap failed");
}
if (slop > 0 && munmap(ret+size-slop, slop) == -1) {
barf("gen_map_mblocks: munmap failed");
}
// ToDo: if we happened to get an aligned block, then don't
// unmap the excess, just use it. For this to work, you
// need to keep in mind the following:
// * Calling my_mmap() with an 'addr' arg pointing to
// already my_mmap()ed space is OK and won't fail.
// * If my_mmap() can't satisfy the request at the
// given 'next_request' address in getMBlocks(), that
// you unmap the extra mblock mmap()ed here (or simply
// satisfy yourself that the slop introduced isn't worth
// salvaging.)
//
// next time, try after the block we just got.
ret += MBLOCK_SIZE - slop;
return ret;
}
// The external interface: allocate 'n' mblocks, and return the
// address.
void *
getMBlocks(nat n)
{
caddr_t ret;
lnat size = MBLOCK_SIZE * n;
nat i;
if (next_request == 0) {
// use gen_map_mblocks the first time.
ret = gen_map_mblocks(size);
} else {
ret = my_mmap(next_request, size);
if (((W_)ret & MBLOCK_MASK) != 0) {
// misaligned block!
#if 0 // defined(DEBUG)
errorBelch("warning: getMBlock: misaligned block %p returned when allocating %d megablock(s) at %p", ret, n, next_request);
#endif
// unmap this block...
if (munmap(ret, size) == -1) {
barf("getMBlock: munmap failed");
}
// and do it the hard way
ret = gen_map_mblocks(size);
}
}
// Next time, we'll try to allocate right after the block we just got.
// ToDo: check that we haven't already grabbed the memory at next_request
next_request = ret + size;
debugTrace(DEBUG_gc, "allocated %d megablock(s) at %p",n,ret);
// fill in the table
for (i = 0; i < n; i++) {
markHeapAlloced( ret + i * MBLOCK_SIZE );
}
mblocks_allocated += n;
return ret;
}
void
freeAllMBlocks(void)
{
/* XXX Do something here */
}
#else /* defined(mingw32_HOST_OS) || defined(cygwin32_HOST_OS) */
/* alloc_rec keeps the info we need to have matching VirtualAlloc and
VirtualFree calls.
*/
typedef struct alloc_rec_ {
char* base; /* non-aligned base address, directly from VirtualAlloc */
int size; /* Size in bytes */
struct alloc_rec_* next;
} alloc_rec;
typedef struct block_rec_ {
char* base; /* base address, non-MBLOCK-aligned */
int size; /* size in bytes */
struct block_rec_* next;
} block_rec;
static alloc_rec* allocs = 0;
static block_rec* free_blocks = 0;
static
alloc_rec*
allocNew(nat n) {
alloc_rec* rec;
rec = (alloc_rec*)stgMallocBytes(sizeof(alloc_rec),"getMBlocks: allocNew");
rec->size = (n+1)*MBLOCK_SIZE;
rec->base =
VirtualAlloc(NULL, rec->size, MEM_RESERVE, PAGE_READWRITE);
if(rec->base==0) {
stgFree((void*)rec);
rec=0;
if (GetLastError() == ERROR_NOT_ENOUGH_MEMORY) {
errorBelch("out of memory");
} else {
sysErrorBelch(
"getMBlocks: VirtualAlloc MEM_RESERVE %d blocks failed", n);
}
} else {
alloc_rec temp;
temp.base=0; temp.size=0; temp.next=allocs;
alloc_rec* it;
it=&temp;
for(; it->next!=0 && it->next->base<rec->base; it=it->next) ;
rec->next=it->next;
it->next=rec;
allocs=temp.next;
debugTrace(DEBUG_gc, "allocated %d megablock(s) at 0x%x",n,(nat)rec->base);
}
return rec;
}
static
void
insertFree(char* alloc_base, int alloc_size) {
block_rec temp;
block_rec* it;
block_rec* prev;
temp.base=0; temp.size=0; temp.next=free_blocks;
it = free_blocks;
prev = &temp;
for( ; it!=0 && it->base<alloc_base; prev=it, it=it->next) {}
if(it!=0 && alloc_base+alloc_size == it->base) {
if(prev->base + prev->size == alloc_base) { /* Merge it, alloc, prev */
prev->size += alloc_size + it->size;
prev->next = it->next;
stgFree(it);
} else { /* Merge it, alloc */
it->base = alloc_base;
it->size += alloc_size;
}
} else if(prev->base + prev->size == alloc_base) { /* Merge alloc, prev */
prev->size += alloc_size;
} else { /* Merge none */
block_rec* rec;
rec = (block_rec*)stgMallocBytes(sizeof(block_rec),"getMBlocks: insertFree");
rec->base=alloc_base;
rec->size=alloc_size;
rec->next = it;
prev->next=rec;
}
free_blocks=temp.next;
}
static
void*
findFreeBlocks(nat n) {
void* ret=0;
block_rec* it;
block_rec temp;
block_rec* prev;
int required_size;
it=free_blocks;
required_size = n*MBLOCK_SIZE;
temp.next=free_blocks; temp.base=0; temp.size=0;
prev=&temp;
/* TODO: Don't just take first block, find smallest sufficient block */
for( ; it!=0 && it->size<required_size; prev=it, it=it->next ) {}
if(it!=0) {
if( (((unsigned long)it->base) & MBLOCK_MASK) == 0) { /* MBlock aligned */
ret = (void*)it->base;
if(it->size==required_size) {
prev->next=it->next;
stgFree(it);
} else {
it->base += required_size;
it->size -=required_size;
}
} else {
char* need_base;
block_rec* next;
int new_size;
need_base = (char*)(((unsigned long)it->base) & ((unsigned long)~MBLOCK_MASK)) + MBLOCK_SIZE;
next = (block_rec*)stgMallocBytes(
sizeof(block_rec)
, "getMBlocks: findFreeBlocks: splitting");
new_size = need_base - it->base;
next->base = need_base +required_size;
next->size = it->size - (new_size+required_size);
it->size = new_size;
next->next = it->next;
it->next = next;
ret=(void*)need_base;
}
}
free_blocks=temp.next;
return ret;
}
/* VirtualAlloc MEM_COMMIT can't cross boundaries of VirtualAlloc MEM_RESERVE,
so we might need to do many VirtualAlloc MEM_COMMITs. We simply walk the
(ordered) allocated blocks. */
static void
commitBlocks(char* base, int size) {
alloc_rec* it;
it=allocs;
for( ; it!=0 && (it->base+it->size)<=base; it=it->next ) {}
for( ; it!=0 && size>0; it=it->next ) {
int size_delta;
void* temp;
size_delta = it->size - (base-it->base);
if(size_delta>size) size_delta=size;
temp = VirtualAlloc(base, size_delta, MEM_COMMIT, PAGE_READWRITE);
if(temp==0) {
sysErrorBelch("getMBlocks: VirtualAlloc MEM_COMMIT failed");
stg_exit(EXIT_FAILURE);
}
size-=size_delta;
base+=size_delta;
}
}
void *
getMBlocks(nat n) {
void* ret;
ret = findFreeBlocks(n);
if(ret==0) {
alloc_rec* alloc;