From 15a64f5a8870b5610b616a4aa753262dfaa5d76e Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Thu, 24 Jun 2021 18:39:36 -0700 Subject: mm/vmalloc: add vmalloc_no_huge Patch series "mm: add vmalloc_no_huge and use it", v4. Add vmalloc_no_huge() and export it, so modules can allocate memory with small pages. Use the newly added vmalloc_no_huge() in KVM on s390 to get around a hardware limitation. This patch (of 2): Commit 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") added support for hugepage vmalloc mappings, it also added the flag VM_NO_HUGE_VMAP for __vmalloc_node_range to request the allocation to be performed with 0-order non-huge pages. This flag is not accessible when calling vmalloc, the only option is to call directly __vmalloc_node_range, which is not exported. This means that a module can't vmalloc memory with small pages. Case in point: KVM on s390x needs to vmalloc a large area, and it needs to be mapped with non-huge pages, because of a hardware limitation. This patch adds the function vmalloc_no_huge, which works like vmalloc, but it is guaranteed to always back the mapping using small pages. This new function is exported, therefore it is usable by modules. [akpm@linux-foundation.org: whitespace fixes, per Christoph] Link: https://lkml.kernel.org/r/20210614132357.10202-1-imbrenda@linux.ibm.com Link: https://lkml.kernel.org/r/20210614132357.10202-2-imbrenda@linux.ibm.com Fixes: 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by: Claudio Imbrenda Reviewed-by: Uladzislau Rezki (Sony) Acked-by: Nicholas Piggin Reviewed-by: David Hildenbrand Acked-by: David Rientjes Cc: Uladzislau Rezki (Sony) Cc: Catalin Marinas Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Christoph Hellwig Cc: Cornelia Huck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/vmalloc.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/vmalloc.h') diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 4d668abb6391..bfaaf0b6fa76 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -135,6 +135,7 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align, const void *caller); void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, int node, const void *caller); +void *vmalloc_no_huge(unsigned long size); extern void vfree(const void *addr); extern void vfree_atomic(const void *addr); -- cgit