Messages in this thread | | | Subject | Re: [PATCH v10 11/12] mm/vmalloc: Hugepage vmalloc mappings | From | Christophe Leroy <> | Date | Mon, 25 Jan 2021 13:13:59 +0100 |
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Le 25/01/2021 à 12:37, Nicholas Piggin a écrit : > Excerpts from Christophe Leroy's message of January 25, 2021 7:14 pm: >> >> >> Le 24/01/2021 à 09:22, Nicholas Piggin a écrit : >>> Support huge page vmalloc mappings. Config option HAVE_ARCH_HUGE_VMALLOC >>> enables support on architectures that define HAVE_ARCH_HUGE_VMAP and >>> supports PMD sized vmap mappings. >>> >>> vmalloc will attempt to allocate PMD-sized pages if allocating PMD size >>> or larger, and fall back to small pages if that was unsuccessful. >>> >>> Architectures must ensure that any arch specific vmalloc allocations >>> that require PAGE_SIZE mappings (e.g., module allocations vs strict >>> module rwx) use the VM_NOHUGE flag to inhibit larger mappings. >>> >>> When hugepage vmalloc mappings are enabled in the next patch, this >>> reduces TLB misses by nearly 30x on a `git diff` workload on a 2-node >>> POWER9 (59,800 -> 2,100) and reduces CPU cycles by 0.54%. >>> >>> This can result in more internal fragmentation and memory overhead for a >>> given allocation, an option nohugevmalloc is added to disable at boot. >>> >>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> >>> --- >>> arch/Kconfig | 10 +++ >>> include/linux/vmalloc.h | 18 ++++ >>> mm/page_alloc.c | 5 +- >>> mm/vmalloc.c | 192 ++++++++++++++++++++++++++++++---------- >>> 4 files changed, 177 insertions(+), 48 deletions(-) >>> >> >>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >>> index 0377e1d059e5..eef61e0f5170 100644 >>> --- a/mm/vmalloc.c >>> +++ b/mm/vmalloc.c >> >>> @@ -2691,15 +2746,18 @@ EXPORT_SYMBOL_GPL(vmap_pfn); >>> #endif /* CONFIG_VMAP_PFN */ >>> >>> static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, >>> - pgprot_t prot, int node) >>> + pgprot_t prot, unsigned int page_shift, >>> + int node) >>> { >>> const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; >>> - unsigned int nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; >>> - unsigned long array_size; >>> - unsigned int i; >>> + unsigned int page_order = page_shift - PAGE_SHIFT; >>> + unsigned long addr = (unsigned long)area->addr; >>> + unsigned long size = get_vm_area_size(area); >>> + unsigned int nr_small_pages = size >> PAGE_SHIFT; >>> struct page **pages; >>> + unsigned int i; >>> >>> - array_size = (unsigned long)nr_pages * sizeof(struct page *); >>> + array_size = (unsigned long)nr_small_pages * sizeof(struct page *); >> >> array_size() is a function in include/linux/overflow.h >> >> For some reason, it breaks the build with your series. > > What config? I haven't seen it. >
Several configs I believe. I saw it this morning in https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20210124082230.2118861-13-npiggin@gmail.com/
Though the reports have all disappeared now.
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