Subversion Repositories planix.SVN

/* Block allocation */
#include        "u.h"
#include        "../port/lib.h"
#include        "mem.h"
#include        "dat.h"
#include        "fns.h"
#include        "error.h"

#define ALIGNUP(a)      ROUND((uintptr)(a), BLOCKALIGN)

enum
{
        Hdrspc          = 64,           /* leave room for high-level headers */
        Bdead           = 0x51494F42,   /* "QIOB" */
        Bmagic          = 0x0910b10c,
};

struct
{
        Lock;
        ulong   bytes;
} ialloc;

/*
 * convert the size of a desired buffer to the size needed
 * to include Block overhead and alignment.
 */
ulong
blocksize(ulong size)
{
        return ALIGNUP(sizeof(Block)) + Hdrspc + ALIGNUP(size);
}

/*
 * convert malloced or non-malloced buffer to a Block.
 * used to build custom Block allocators.
 *
 * buf must be at least blocksize(usable) bytes.
 */
Block *
mem2block(void *buf, ulong usable, int malloced)
{
        Block *b;

        if(buf == nil)
                return nil;

        b = (Block *)buf;
        b->next = nil;
        b->list = nil;
        b->free = 0;
        b->flag = 0;
        b->ref = 0;
        b->magic = Bmagic;
        _xinc(&b->ref);

        /* align start of data portion by rounding up */
        b->base = (uchar*)ALIGNUP((ulong)b + sizeof(Block));

        /* align end of data portion by rounding down */
        b->lim = (uchar*)b + (malloced? msize(b): blocksize(usable));
        b->lim = (uchar*)((ulong)b->lim & ~(BLOCKALIGN-1));

        /* leave sluff at beginning for added headers */
        b->wp = b->rp = b->lim - ALIGNUP(usable);
        if(b->rp < b->base)
                panic("mem2block: b->rp < b->base");
        if(b->lim > (uchar*)b + (malloced? msize(b): blocksize(usable)))
                panic("mem2block: b->lim beyond Block end");
        return b;
}

static Block*
_allocb(int size)
{
        return mem2block(mallocz(blocksize(size), 0), size, 1);
}

Block*
allocb(int size)
{
        Block *b;

        /*
         * Check in a process and wait until successful.
         * Can still error out of here, though.
         */
        if(up == nil)
                panic("allocb without up: %#p", getcallerpc(&size));
        if((b = _allocb(size)) == nil){
                splhi();
                xsummary();
                mallocsummary();
                delay(500);
                panic("allocb: no memory for %d bytes; caller %#p", size,
                        getcallerpc(&size));
        }
        setmalloctag(b, getcallerpc(&size));

        return b;
}

Block*
iallocb(int size)
{
        Block *b;
        static int m1, m2, mp;

        if(ialloc.bytes > conf.ialloc){
                if((m1++%10000)==0){
                        if(mp++ > 1000){
                                active.exiting = 1;
                                exit(0);
                        }
                        iprint("iallocb: limited %lud/%lud\n",
                                ialloc.bytes, conf.ialloc);
                }
                return nil;
        }

        if((b = _allocb(size)) == nil){
                if((m2++%10000)==0){
                        if(mp++ > 1000){
                                active.exiting = 1;
                                exit(0);
                        }
                        iprint("iallocb: no memory %lud/%lud\n",
                                ialloc.bytes, conf.ialloc);
                }
                return nil;
        }
        setmalloctag(b, getcallerpc(&size));
        b->flag = BINTR;

        ilock(&ialloc);
        ialloc.bytes += b->lim - b->base;
        iunlock(&ialloc);

        return b;
}

void
freeb(Block *b)
{
        void *dead = (void*)Bdead;
        long ref;

        if(b == nil)
                return;
        if(Bmagic && b->magic != Bmagic)
                panic("freeb: bad magic %#lux in Block %#p; caller pc %#p",
                        b->magic, b, getcallerpc(&b));

        if((ref = _xdec(&b->ref)) > 0)
                return;
        if(ref < 0){
                dumpstack();
                panic("freeb: ref %ld; caller pc %#p", ref, getcallerpc(&b));
        }

        /*
         * drivers which perform non cache coherent DMA manage their own buffer
         * pool of uncached buffers and provide their own free routine.
         */
        if(b->free) {
                b->free(b);
                return;
        }
        if(b->flag & BINTR) {
                ilock(&ialloc);
                ialloc.bytes -= b->lim - b->base;
                iunlock(&ialloc);
        }

        /* poison the block in case someone is still holding onto it */
        b->next = dead;
        b->rp = dead;
        b->wp = dead;
        b->lim = dead;
        b->base = dead;
        b->magic = 0;

        free(b);
}

void
checkb(Block *b, char *msg)
{
        void *dead = (void*)Bdead;

        if(b == dead)
                panic("checkb b %s %#p", msg, b);
        if(b->base == dead || b->lim == dead || b->next == dead
          || b->rp == dead || b->wp == dead){
                print("checkb: base %#p lim %#p next %#p\n",
                        b->base, b->lim, b->next);
                print("checkb: rp %#p wp %#p\n", b->rp, b->wp);
                panic("checkb dead: %s", msg);
        }
        if(Bmagic && b->magic != Bmagic)
                panic("checkb: bad magic %#lux in Block %#p", b->magic, b);
        if(b->base > b->lim)
                panic("checkb 0 %s %#p %#p", msg, b->base, b->lim);
        if(b->rp < b->base)
                panic("checkb 1 %s %#p %#p", msg, b->base, b->rp);
        if(b->wp < b->base)
                panic("checkb 2 %s %#p %#p", msg, b->base, b->wp);
        if(b->rp > b->lim)
                panic("checkb 3 %s %#p %#p", msg, b->rp, b->lim);
        if(b->wp > b->lim)
                panic("checkb 4 %s %#p %#p", msg, b->wp, b->lim);
}

void
iallocsummary(void)
{
        print("ialloc %lud/%lud\n", ialloc.bytes, conf.ialloc);
}