Messages in this thread | | | Date | Mon, 3 Mar 2003 14:15:18 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 2.5.63] Teach page_mapped about the anon flag |
| |
Dave McCracken <dmccr@us.ibm.com> wrote: > > > --On Monday, March 03, 2003 13:35:39 -0800 Andrew Morton <akpm@digeo.com> > wrote: > > > We do need a patch I think. page_mapped() is still assuming that an > > all-bits-zero atomic_t corresponds to a zero-value atomic_t. > > > > This does appear to be true for all supported architectures, but it's a > > bit grubby. > > If that's ever not true then we need extra code to initialize/rezero that > field, since we assume it's zero on alloc, and the pte_chain code also > assumes it's zero for a new page.
Well why not make mapcount an "int" and move the places where it is modified inside pte_chain_lock()?
That does not increase the number of atomic operations, and it makes me stop wondering if this:
if (atomic_read(&page->pte.mapcount) == 0) inc_page_state(nr_mapped);
is racy ;)
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |