diff options
| author | Claudio Imbrenda <imbrenda@linux.ibm.com> | 2021-06-24 18:39:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-24 19:40:53 -0700 |
| commit | 15a64f5a8870b5610b616a4aa753262dfaa5d76e (patch) | |
| tree | bc3b8e5b0d343720387a9ddbfd19095d1b265cdd /mm/vmalloc.c | |
| parent | 8fd0c1b0647a6bda4067ee0cd61e8395954b6f28 (diff) | |
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 <imbrenda@linux.ibm.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a13ac524f6ff..fada19e17814 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2999,6 +2999,23 @@ void *vmalloc(unsigned long size) EXPORT_SYMBOL(vmalloc); /** + * vmalloc_no_huge - allocate virtually contiguous memory using small pages + * @size: allocation size + * + * Allocate enough non-huge pages to cover @size from the page level + * allocator and map them into contiguous kernel virtual space. + * + * Return: pointer to the allocated memory or %NULL on error + */ +void *vmalloc_no_huge(unsigned long size) +{ + return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, + GFP_KERNEL, PAGE_KERNEL, VM_NO_HUGE_VMAP, + NUMA_NO_NODE, __builtin_return_address(0)); +} +EXPORT_SYMBOL(vmalloc_no_huge); + +/** * vzalloc - allocate virtually contiguous memory with zero fill * @size: allocation size * |