[PATCH] HACK: Atari ST-RAM allocator using fixed pool of bootmem
Hi,
> As to your question regarding the most generic fix: if there really is not
> enough ST-RAM (i.e. the available space is taken by the kernel and the
> ramdisk, after 'unpacking' the ramdisk to the buffer cache) we'd need to
> either make the ramdisk unpack go to non-DMA memory (no idea here;
> ideally the buffer cache should not have a preference for DMA memory in
> this case), or reserve a chunk of memory up front (tried that in a hackish
> way).
Slightly less hackish implementation of that hack attached. This (on top
of my max_dma_address patch before) does solve the ramdisk related atafb
problems without resorting to artificial RAM limits. Stephen, please try
this patch.
--- arch/m68k/atari/stram.c.pool.org 2007-12-31 21:50:45.000000000 +1300
+++ arch/m68k/atari/stram.c 2008-01-02 17:51:38.000000000 +1300
@@ -30,7 +30,7 @@
#include <asm/io.h>
#include <asm/semaphore.h>
-#undef DEBUG
+#define DEBUG
#ifdef DEBUG
#define DPRINTK(fmt,args...) printk( fmt, ##args )
@@ -90,11 +90,15 @@
/* values for flags field */
#define BLOCK_FREE 0x01 /* free structure in the BLOCKs pool */
#define BLOCK_KMALLOCED 0x02 /* structure allocated by kmalloc() */
+#define BLOCK_POOL 0x04 /* block allocated from static pool */
#define BLOCK_GFP 0x08 /* block allocated with __get_dma_pages() */
/* list of allocated blocks */
static BLOCK *alloc_list;
+static BLOCK *stram_free_list;
+static unsigned long stram_pool, stram_pool_start, stram_pool_end;
+
/* We can't always use kmalloc() to allocate BLOCK structures, since
* stram_alloc() can be called rather early. So we need some pool of
* statically allocated structures. 20 of them is more than enough, so in most
@@ -155,6 +159,10 @@
if (!kernel_in_stram)
reserve_bootmem (0, PAGE_SIZE);
+ stram_pool = (unsigned long) alloc_bootmem_low(512*1024);
+ stram_pool_start = stram_pool;
+ stram_pool_end = stram_pool + 512*1024 - 1;
+ DPRINTK("atari_stram pool, start=%08lx, end=%08lx\n", stram_pool, stram_pool_end);
}
void atari_stram_mem_init_hook (void)
@@ -162,6 +170,38 @@
mem_init_done = 1;
}
+/* find a region (by size) in the free list */
+static void *find_free_stram( long size )
+{
+ BLOCK *p,*q,*r;
+ unsigned long item;
+
+ q=NULL;
+ r=stram_free_list;
+ for( p = stram_free_list; p; p = p->next ) {
+ if (p->size >= size) {
+ q=p;
+ break;
+ }
+ r=p;
+ }
+
+ /* remove from free list - FIXME, untested! */
+ if (q) {
+ item = (unsigned long) q->start;
+ r->next = q->next;
+ return (void *) item;
+ }
+ /* take from pool */
+ if ( (stram_pool_end - stram_pool) > size) {
+ item = stram_pool;
+ stram_pool += size;
+ return (void *) item;
+ }
+
+ return( NULL );
+}
+
/*
* This is main public interface: somehow allocate a ST-RAM block
@@ -188,11 +228,17 @@
if (!mem_init_done)
return alloc_bootmem_low(size);
else {
+ if ((addr = find_free_stram(size)) != NULL) {
+ flags = BLOCK_POOL;
+ DPRINTK( "atari_stram_alloc: after mem_init, "
+ "find_free_Stram=%p\n", addr );
+ } else {
/* After mem_init(): can only resort to __get_dma_pages() */
- addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size));
- flags = BLOCK_GFP;
+ addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size));
+ flags = BLOCK_GFP;
+ DPRINTK( "atari_stram_alloc: after mem_init, "
"get_pages=%p\n", addr );
+ }
}
if (addr) {
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