Linus Torvalds wrote:
> On Fri, 9 May 2003, Dave Hansen wrote:
>
>>We've been playing with patches in the -mjb tree which make PAGE_OFFSET
>>and TASK_SIZE move to some weird values. I have it to the point where I
>>could do a 3.875:0.125 user:kernel split.
>
> That's still not "weird" in the current sense.
>
> We've always (well, for a long time) been able to handle a TASK_SIZE that
> has a 111..00000 pattern - and in fact we used to _depend_ on that kind of
> pattern, because macros like "virt_to_phys()" were simple bitwise-and
> operations. There may be some code in the kernel that still depends on
> that kind of bitwise operation with TASK_SIZE.
>
> Your 3.875:0.125 split still fits that pattern, and thus doesn't create
> any new cases.
>
> In contrast, a TASK_SIZE of 0xc1000000 can no longer just "mask off" the
> kernel address bits. And _that_ is what I meant with "strange value".
Ahhh, weird*er* :)
These patches at least address a small class of problems where it is
assumed that the kernel pagetable entries start at the beginning of a
pmd. Anyway, 2.5.68-mjb3 boots with a 0xE1000000 PAGE_OFFSET with PAE
on a 4GB machine. It does "just work", at least in Martin's tree.
3343MB HIGHMEM available.
368MB LOWMEM available.
elm3b82:~# cat /proc/meminfo
MemTotal: 3758468 kB
MemFree: 3728368 kB
Buffers: 1696 kB
Cached: 8184 kB
SwapCached: 0 kB
Active: 7640 kB
Inactive: 4936 kB
HighTotal: 3424228 kB
HighFree: 3412224 kB
LowTotal: 334240 kB
LowFree: 316144 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 304 kB
Writeback: 0 kB
Mapped: 5900 kB
Slab: 6292 kB
Committed_AS: 7024 kB
PageTables: 472 kB
VmallocTotal: 114680 kB
VmallocUsed: 2400 kB
VmallocChunk: 112280 kB
-- Dave Hansen haveblue@us.ibm.com- 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/
This archive was generated by hypermail 2b29 : Thu May 15 2003 - 22:00:31 EST