Messages in this thread | | | Date | Thu, 7 Feb 2008 09:09:30 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86_64: fix page table size |
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* Yinghai Lu <Yinghai.Lu@Sun.COM> wrote:
> [PATCH] x86_64: fix page table size
> Entering add_active_range(0, 1048576, 67239936) 2 entries of 3200 used > end_pfn_map = 67239936 > Kernel panic - not syncing: Overlapping early reservations 8000-109fff > PGTABLE to 9bc00-9dbff EBDA > > change back the logic. we DO need extra space for pmds when > direct_gbpages is not there.
> @@ -370,7 +370,7 @@ static void __init find_early_table_space(unsigned long end) > > puds = (end + PUD_SIZE - 1) >> PUD_SHIFT; > tables = round_up(puds * sizeof(pud_t), PAGE_SIZE); > - if (direct_gbpages) { > + if (!direct_gbpages) {
thanks Yinghai, applied!
I'm wondering why this bug didnt trigger more widely. It seems to me it needs some serious amount of RAM to trigger this bug - correct?
btw., it would be nice to have some "lots of RAM simulation" debugging code which would just _fake_ a really large e820 map and would in the end throw away the 'fake' pages later during bootup. Perhaps tell the early allocator to never allocate into these fake areas [via an struct e820 entry flag], but all our sizing code and the boot bitmaps, etc. would be sized accordingly, as if we had this much RAM - and we'd trigger these nuances. We could put this into a new "fakemem=128GB" boot option and hence we could boot with fakemem=128GB on a 2GB box and could at least hope to be able to boot [with some serious amount of RAM wasted on over-sized pagetables, allocator bitmaps and mem_map[]]. Hm?
Ingo
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