On Sat, 10 Nov 2018 23:41:34 -0500 Qian Cai <cai@xxxxxx> wrote: > It was broken somewhere between b00d209241ff and 3541833fd1f2. > > [ 0.000000] cannot allocate crashkernel (size:0x20000000) > > Where a good one looks like this, > > [ 0.000000] crashkernel reserved: 0x0000000008600000 - 0x0000000028600000 (512 MB) > > Some commits look more suspicious than others. > > mm: add mm_pxd_folded checks to pgtable_bytes accounting functions > mm: introduce mm_[p4d|pud|pmd]_folded > mm: make the __PAGETABLE_PxD_FOLDED defines non-empty The intent of these three patches is to add extra checks to the pgtable_bytes accounting function. If applied incorrectly the expected result would be warnings like this: BUG: non-zero pgtables_bytes on freeing mm: 16384 The change Linus worried about affects the __PAGETABLE_PxD_FOLDED defines. These defines are used with #ifdef, #ifndef, and __is_defined() for the new mm_p?d_folded() macros. I can not see how this would make a difference for your iomem setup. > # diff -u ../iomem.good.txt ../iomem.bad.txt > --- ../iomem.good.txt 2018-11-10 22:28:20.092614398 -0500 > +++ ../iomem.bad.txt 2018-11-10 20:39:54.930294479 -0500 > @@ -1,9 +1,8 @@ > 00000000-3965ffff : System RAM > 00080000-018cffff : Kernel code > - 018d0000-020affff : reserved > - 020b0000-045affff : Kernel data > - 08600000-285fffff : Crash kernel > - 28730000-2d5affff : reserved > + 018d0000-0762ffff : reserved > + 07630000-09b2ffff : Kernel data > + 231b0000-2802ffff : reserved > 30ec0000-30ecffff : reserved > 35660000-3965ffff : reserved > 39660000-396fffff : reserved > @@ -127,7 +126,7 @@ > 7c5200000-7c520ffff : 0004:48:00.0 > 1040000000-17fbffffff : System RAM > 13fbfd0000-13fdfdffff : reserved > - 16fba80000-17fbfdffff : reserved > + 16fafd0000-17fbfdffff : reserved > 17fbfe0000-17fbffffff : reserved > 1800000000-1ffbffffff : System RAM > 1bfbff0000-1bfdfeffff : reserved The easiest way to verify if the three commits have something to do with your problem is to revert them and run your test. Can you do that please ? -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.
