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

Also common-up some duplicate bits in the platform-specific code

1 files changed, 227 insertions, 2 deletions

diff --git a/rts/win32/OSMem.c b/rts/win32/OSMem.c
index cdecf02985..f4c126403a 100644
--- a/rts/win32/OSMem.c
+++ b/rts/win32/OSMem.c
@@ -1,14 +1,239 @@
 /* -----------------------------------------------------------------------------
  *
- * (c) The University of Glasgow 2006
+ * (c) The University of Glasgow 2006-2007
  *
  * OS-specific memory management
  *
  * ---------------------------------------------------------------------------*/
 
-#include <windows.h>
 #include "Rts.h"
 #include "OSMem.h"
+#include "RtsUtils.h"
+#include "RtsMessages.h"
+
+#if HAVE_WINDOWS_H
+#include <windows.h>
+#endif
+
+/* 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 = NULL;
+static block_rec* free_blocks = NULL;
+
+void
+osMemInit(void)
+{
+    allocs = NULL;
+    free_blocks = NULL;
+}
+
+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;
+    }
+    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 *
+osGetMBlocks(nat n) {
+    void* ret;
+    ret = findFreeBlocks(n);
+    if(ret==0) {
+        alloc_rec* alloc;
+        alloc = allocNew(n);
+        /* We already belch in allocNew if it fails */
+	if (alloc == 0) {
+	    stg_exit(EXIT_FAILURE);
+	} else {
+            insertFree(alloc->base, alloc->size);
+            ret = findFreeBlocks(n);
+	}
+    }
+
+    if(ret!=0) {
+        /* (In)sanity tests */
+        if (((W_)ret & MBLOCK_MASK) != 0) {
+            barf("getMBlocks: misaligned block returned");
+        }
+
+        commitBlocks(ret, MBLOCK_SIZE*n);
+    }
+
+    return ret;
+}
+
+void
+osFreeAllMBlocks(void)
+{
+    {
+        block_rec* next;
+        block_rec* it;
+        next=0;
+        it = free_blocks;
+        for(; it!=0; ) {
+            next = it->next;
+            stgFree(it);
+            it=next;
+        }
+    }
+    {
+        alloc_rec* next;
+        alloc_rec* it;
+        next=0;
+        it=allocs;
+        for(; it!=0; ) {
+            if(!VirtualFree((void*)it->base, 0, MEM_RELEASE)) {
+                sysErrorBelch("freeAllMBlocks: VirtualFree MEM_RELEASE failed");
+		stg_exit(EXIT_FAILURE);
+            }
+            next = it->next;
+            stgFree(it);
+            it=next;
+        }
+    }
+}
 
 lnat getPageSize (void)
 {