On Sun, Feb 03, 2019 at 08:39:20PM +1100, Michael Ellerman wrote: > Mike Rapoport <rppt@xxxxxxxxxxxxx> writes: > > > Currently, memblock has several internal functions with overlapping > > functionality. They all call memblock_find_in_range_node() to find free > > memory and then reserve the allocated range and mark it with kmemleak. > > However, there is difference in the allocation constraints and in fallback > > strategies. > > > > The allocations returning physical address first attempt to find free > > memory on the specified node within mirrored memory regions, then retry on > > the same node without the requirement for memory mirroring and finally fall > > back to all available memory. > > > > The allocations returning virtual address start with clamping the allowed > > range to memblock.current_limit, attempt to allocate from the specified > > node from regions with mirroring and with user defined minimal address. If > > such allocation fails, next attempt is done with node restriction lifted. > > Next, the allocation is retried with minimal address reset to zero and at > > last without the requirement for mirrored regions. > > > > Let's consolidate various fallbacks handling and make them more consistent > > for physical and virtual variants. Most of the fallback handling is moved > > to memblock_alloc_range_nid() and it now handles node and mirror fallbacks. > > > > The memblock_alloc_internal() uses memblock_alloc_range_nid() to get a > > physical address of the allocated range and converts it to virtual address. > > > > The fallback for allocation below the specified minimal address remains in > > memblock_alloc_internal() because memblock_alloc_range_nid() is used by CMA > > with exact requirement for lower bounds. > > This is causing problems on some of my machines. > > I see NODE_DATA allocations falling back to node 0 when they shouldn't, > or didn't previously. > > eg, before: > > 57990190: (116011251): numa: NODE_DATA [mem 0xfffe4980-0xfffebfff] > 58152042: (116373087): numa: NODE_DATA [mem 0x8fff90980-0x8fff97fff] > > after: > > 16356872061562: (6296877055): numa: NODE_DATA [mem 0xfffe4980-0xfffebfff] > 16356872079279: (6296894772): numa: NODE_DATA [mem 0xfffcd300-0xfffd497f] > 16356872096376: (6296911869): numa: NODE_DATA(1) on node 0 > > > On some of my other systems it does that, and then panics because it > can't allocate anything at all: > > [ 0.000000] numa: NODE_DATA [mem 0x7ffcaee80-0x7ffcb3fff] > [ 0.000000] numa: NODE_DATA [mem 0x7ffc99d00-0x7ffc9ee7f] > [ 0.000000] numa: NODE_DATA(1) on node 0 > [ 0.000000] Kernel panic - not syncing: Cannot allocate 20864 bytes for node 16 data > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc4-gccN-next-20190201-gdc4c899 #1 > [ 0.000000] Call Trace: > [ 0.000000] [c0000000011cfca0] [c000000000c11044] dump_stack+0xe8/0x164 (unreliable) > [ 0.000000] [c0000000011cfcf0] [c0000000000fdd6c] panic+0x17c/0x3e0 > [ 0.000000] [c0000000011cfd90] [c000000000f61bc8] initmem_init+0x128/0x260 > [ 0.000000] [c0000000011cfe60] [c000000000f57940] setup_arch+0x398/0x418 > [ 0.000000] [c0000000011cfee0] [c000000000f50a94] start_kernel+0xa0/0x684 > [ 0.000000] [c0000000011cff90] [c00000000000af70] start_here_common+0x1c/0x52c > [ 0.000000] Rebooting in 180 seconds.. > > > So there's something going wrong there, I haven't had time to dig into > it though (Sunday night here). I'll try to see if I can reproduce it with qemu. > cheers > -- Sincerely yours, Mike.
