Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> writes: >> About PPC64, your patchset fixes the issue as the population gets followed by a >> sparse_init_one_section(). >> >> It can be seen here: >> >> Before: >> >> kernel: vmemmap_populate f000000000000000..f000000000004000, node 0 >> kernel: * f000000000000000..f000000000010000 allocated at (____ptrval____) >> kernel: vmemmap_populate f000000000000000..f000000000008000, node 0 >> kernel: * f000000000000000..f000000000010000 allocated at (____ptrval____) >> kernel: vmemmap_populate f000000000000000..f00000000000c000, node 0 >> kernel: * f000000000000000..f000000000010000 allocated at (____ptrval____) >> >> >> After: >> >> kernel: vmemmap_populate f000000000000000..f000000000004000, node 0 >> kernel: * f000000000000000..f000000000010000 allocated at (____ptrval____) >> kernel: vmemmap_populate f000000000000000..f000000000008000, node 0 >> kernel: vmemmap_populate f000000000000000..f00000000000c000, node 0 >> kernel: vmemmap_populate f000000000000000..f000000000010000, node 0 >> kernel: vmemmap_populate f000000000010000..f000000000014000, node 0 >> kernel: * f000000000010000..f000000000020000 allocated at (____ptrval____) >> >> >> As can be seen, before the patchset, we keep calling vmemmap_create_mapping() even if we >> populated that section already, because of vmemmap_populated() checking for SECTION_HAS_MEM_MAP. >> >> After the patchset, since each population is being followed by a call to sparse_init_one_section(), >> when vmemmap_populated() gets called, we have SECTION_HAS_MEM_MAP already in case the section >> was populated. > > Hi Oscar, > > Right, I also like that this solution removes one extra loop, thus > reduces the code size. We were populating pages in one place, and then > loop again to set sections, now we do both in one place, but still > allow preallocation of memory to reduces fragmentation on all > platforms. However, I still wanted to see if someone could test on > real hardware. I booted it on a small VM and a 160 CPU 4 node machine, both booted fine. If you want: Tested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> (powerpc) Thanks for fixing it up for us. cheers
