Date: Tue, 16 Oct 2001 14:42:17 +0900 From: "Eugene M. Kim" <ab@astralblue.net> To: freebsd-hackers@freebsd.org Subject: contigmalloc + contigfree = memory leak? Message-ID: <20011016144217.A35188@the-7.net>
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Greetings,
QUESTION:
Does contigfree() really free up memory allocated using contigmalloc()?
BACKGROUND:
I've been trying to make up a kmod that allocates/deallocates memory in
a specific physical address range. Mike Smith suggested using busdma
functions to do the job, so I followed it.
After allocating and deallocating memory several times, it seemed that
bus_dmamem_free() was not freeing the memory properly. I looked at
busdma_machdep.c where bus_dmamem_free() was defined, and found:
void
bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
{
/*
* dmamem does not need to be bounced, so the map should be
* NULL
*/
if (map != NULL)
panic("bus_dmamem_free: Invalid map freed\n");
/* XXX There is no "contigfree" and "free" doesn't work */
if ((dmat->maxsize <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem))
free(vaddr, M_DEVBUF);
}
However, there *is* contigfree() and a related patch was applied on
-current around August, so I did the same thing (adding an else clause
to call contigfree(vaddr, dmat->maxsize, M_DEVBUF)).
It didn't solve the memory leak problem either, so I'm stuck here...
Could anyone shed a light on this?
Regards,
Eugene
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