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mm/vmalloc: hugepage vmalloc mappings

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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.

This can result in more internal fragmentation and memory overhead for a
given allocation, an option nohugevmalloc is added to disable at boot.

[colin.king@canonical.com: fix read of uninitialized pointer area]
  Link: https://lkml.kernel.org/r/20210318155955.18220-1-colin.king@canonical.com

Link: https://lkml.kernel.org/r/20210317062402.533919-14-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nicholas Piggin
2021-04-29 22:58:49 -07:00
committed by Linus Torvalds
parent 5d87510de1
commit 121e6f3258
4 changed files with 210 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
include/linux/vmalloc.h
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@@ -26,6 +26,7 @@ struct notifier_block; /* in notifier.h */
#define VM_KASAN 0x00000080 /* has allocated kasan shadow memory */
#define VM_FLUSH_RESET_PERMS 0x00000100 /* reset direct map and flush TLB on unmap, can't be freed in atomic context */
#define VM_MAP_PUT_PAGES 0x00000200 /* put pages and free array in vfree */
#define VM_NO_HUGE_VMAP 0x00000400 /* force PAGE_SIZE pte mapping */
/*
* VM_KASAN is used slighly differently depending on CONFIG_KASAN_VMALLOC.
@@ -54,6 +55,9 @@ struct vm_struct {
unsigned long size;
unsigned long flags;
struct page **pages;
#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
unsigned int page_order;
#endif
unsigned int nr_pages;
phys_addr_t phys_addr;
const void *caller;
@@ -188,6 +192,22 @@ void free_vm_area(struct vm_struct *area);
extern struct vm_struct *remove_vm_area(const void *addr);
extern struct vm_struct *find_vm_area(const void *addr);
static inline bool is_vm_area_hugepages(const void *addr)
{
/*
* This may not 100% tell if the area is mapped with > PAGE_SIZE
* page table entries, if for some reason the architecture indicates
* larger sizes are available but decides not to use them, nothing
* prevents that. This only indicates the size of the physical page
* allocated in the vmalloc layer.
*/
#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
return find_vm_area(addr)->page_order > 0;
#else
return false;
#endif
}
#ifdef CONFIG_MMU
int vmap_range(unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
@@ -205,6 +225,7 @@ static inline void set_vm_flush_reset_perms(void *addr)
if (vm)
vm->flags |= VM_FLUSH_RESET_PERMS;
}
#else
static inline int
map_kernel_range_noflush(unsigned long start, unsigned long size,