From 462951cd32e1496dc64b00051dfb777efc8ae5d8 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Mon, 26 Nov 2018 12:59:16 +1100 Subject: powerpc/mm: Fix linux page tables build with some configs For some configs the build fails with: arch/powerpc/mm/dump_linuxpagetables.c: In function 'populate_markers': arch/powerpc/mm/dump_linuxpagetables.c:306:39: error: 'PKMAP_BASE' undeclared (first use in this function) arch/powerpc/mm/dump_linuxpagetables.c:314:50: error: 'LAST_PKMAP' undeclared (first use in this function) These come from highmem.h, including that fixes the build. Signed-off-by: Michael Ellerman --- arch/powerpc/mm/dump_linuxpagetables.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/powerpc/mm') diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c index 2b74f8adf4d0..6aa41669ac1a 100644 --- a/arch/powerpc/mm/dump_linuxpagetables.c +++ b/arch/powerpc/mm/dump_linuxpagetables.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include -- cgit v1.2.3 From 9ef34630a4614ee1cd478f9859ebea55d55f10ec Mon Sep 17 00:00:00 2001 From: Oliver O'Halloran Date: Fri, 7 Dec 2018 02:17:14 +1100 Subject: powerpc/mm: Fallback to RAM if the altmap is unusable The "altmap" is used to provide a pool of memory that is reserved for the vmemmap backing of hot-plugged memory. This is useful when adding large amount of ZONE_DEVICE memory to a system with a limited amount of normal memory. On ppc64 we use huge pages to map the vmemmap which requires the backing storage to be contigious and aligned to the hugepage size. The altmap implementation allows for the altmap provider to reserve a few PFNs at the start of the range for it's own uses and when this occurs the first chunk of the altmap is not usable for hugepage mappings. On hash there is no sane way to fall back to a normal sized page mapping so we fail the allocation. This results in memory hotplug failing with ENOMEM when the new range doesn't fall into an existing vmemmap block. This patch handles this case by falling back to using system memory rather than failing if we cannot allocate from the altmap. This fallback should only ever be used for the first vmemmap block so it should not cause excess memory consumption. Fixes: 7b73d978a5d0 ("mm: pass the vmem_altmap to vmemmap_populate") Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman --- arch/powerpc/mm/init_64.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/mm') diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index 7a9886f98b0c..a5091c034747 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -188,15 +188,20 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node); for (; start < end; start += page_size) { - void *p; + void *p = NULL; int rc; if (vmemmap_populated(start, page_size)) continue; + /* + * Allocate from the altmap first if we have one. This may + * fail due to alignment issues when using 16MB hugepages, so + * fall back to system memory if the altmap allocation fail. + */ if (altmap) p = altmap_alloc_block_buf(page_size, altmap); - else + if (!p) p = vmemmap_alloc_block_buf(page_size, node); if (!p) return -ENOMEM; @@ -255,8 +260,15 @@ void __ref vmemmap_free(unsigned long start, unsigned long end, { unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; unsigned long page_order = get_order(page_size); + unsigned long alt_start = ~0, alt_end = ~0; + unsigned long base_pfn; start = _ALIGN_DOWN(start, page_size); + if (altmap) { + alt_start = altmap->base_pfn; + alt_end = altmap->base_pfn + altmap->reserve + + altmap->free + altmap->alloc + altmap->align; + } pr_debug("vmemmap_free %lx...%lx\n", start, end); @@ -280,8 +292,9 @@ void __ref vmemmap_free(unsigned long start, unsigned long end, page = pfn_to_page(addr >> PAGE_SHIFT); section_base = pfn_to_page(vmemmap_section_start(start)); nr_pages = 1 << page_order; + base_pfn = PHYS_PFN(addr); - if (altmap) { + if (base_pfn >= alt_start && base_pfn < alt_end) { vmem_altmap_free(altmap, nr_pages); } else if (PageReserved(page)) { /* allocated from bootmem */ -- cgit v1.2.3