Messages in this thread | | | Date | Tue, 15 Apr 2008 18:17:24 -0700 | From | "Yinghai Lu" <> | Subject | Re: [patch] mm: sparsemem memory_present() memory corruption fix |
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On Tue, Apr 15, 2008 at 6:02 PM, Ingo Molnar <mingo@elte.hu> wrote: > > * Yinghai Lu <yhlu.kernel@gmail.com> wrote: > > > On Tue, Apr 15, 2008 at 5:44 PM, Ingo Molnar <mingo@elte.hu> wrote: > > > > > > * Yinghai Lu <yhlu.kernel@gmail.com> wrote: > > > > > > > > + unsigned long max_arch_pfn = 1ULL << (MAX_PHYSMEM_BITS-PAGE_SHIFT); > > > > > > > > > > and also check my analysis whether it is correct and whether it > > > > > matches the reported bug patterns. But otherwise the fix looks like > > > > > a safe fix for v2.6.25-final to me - it only filters out values > > > > > from sparsemem input that are nonsensical in the sparsemem > > > > > framework anyway. > > > > > > > > > > > can you check why find_max_pfn() e820_32.c need to call > > > > memory_present? wonder if it can be removed. > > > > > > this is the only call to memory_present() we do in 32-bit arch setup, so > > > it's required. > > > > > > (the function find_max_pfn() is woefully misnamed, but that's a cleanup > > > - i just fixed this in x86.git.) > > > > 64 bit is calling that via paging_init > > ==>sparse_memory_present_with_active_regions(MAX_NUMNODES). > > > > and > > void __init sparse_memory_present_with_active_regions(int nid) > > yeah - 64-bit is different here and it's not affected by the problem > because there SECTION_SIZE_BITS is 27 (==128 MB chunks), > MAX_PHYSADDR_BITS is 40 (== 1 TB) - giving 8192 section map entries. > Once larger than 1 TB 64-bit x86 systems are created MAX_PHYSADDR_BITS > needs to be increased.
also 64 bit early_node_map[10] active PFN ranges 0: 0 -> 149 0: 256 -> 917408 0: 1048576 -> 8519680 1: 8519680 -> 16908288 2: 16908288 -> 25296896 3: 25296896 -> 33685504 4: 33685504 -> 42074112 5: 42074112 -> 50462720 6: 50462720 -> 58851328 7: 58851328 -> 67239936
and 32 bit only has one entry [ 0.000000] early_node_map[1] active PFN ranges [ 0.000000] 0: 0 -> 1048576
YH
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