kvaddr = kmalloc(size, ...) // where size is n*PAGE_SIZE
...
{
void* adr= kvaddr;
unsigned long page;
unsigned int sz = size;
while (sz > 0)
{
mem_map_reserve(MAP_NR(adr));
adr += PAGE_SIZE;
sz -= PAGE_SIZE;
}
}
what is the sense of the comment in include/linux/mm.h ?
/*
* Various page->flags bits:
*
* PG_reserved is set for a page which must never be accessed (which
* may not even be present).
*
...
"which must never be accessed" refers to the I/O subsystem, doesn't it ?
or to generically to code instructions ?
I'm curious, what is that bit for ?
I experimented the effect: user space doesn't see any modification made
from kernel code or PCI DMA access.
ciao
-- +------------------------------------------------------------------+ |Rossetti Davide INFN - Sezione Roma I - gruppo V, prog. APEmille| | web : http://apemaia.roma1.infn.it/~rossetti | | """"" E-mail : davide.rossetti@roma1.infn.it | | |o o| phone : (+39)-6-49914412 | |--o00O-O00o-- fax : (+39)-6-4957697 | | address: Dipartimento di Fisica (V.E.) | | Universita' di Roma "La Sapienza" | | P.le Aldo Moro,5 I - 00185 Roma - Italy| | pgp pub. key: finger rossetti@apemaia.roma1.infn.it | | | |"Most people think about twice a year. I got famous by thinking | | once a week." - George B. Shaw | +------------------------------------------------------------------+- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/