Messages in this thread Patch in this message | | | From | Glauber Costa <> | Subject | [PATCH 4/4] Do not use guard pages in non-debug kernels | Date | Fri, 7 Nov 2008 20:35:54 -0200 |
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In mm/vmalloc.c, make usage of guard pages dependant on CONFIG_DEBUG_PAGEALLOC.
Signed-off-by: Glauber Costa <glommer@redhat.com> --- mm/vmalloc.c | 25 +++++++++++++++---------- 1 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 6fe2003..ed73c6f 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -28,6 +28,11 @@ #include <asm/uaccess.h> #include <asm/tlbflush.h> +#ifdef CONFIG_DEBUG_PAGEALLOC +#define GUARD_PAGE_SIZE PAGE_SIZE +#else +#define GUARD_PAGE_SIZE 0 +#endif /*** Page table manipulation functions ***/ @@ -363,7 +368,7 @@ retry: } while (addr + size >= first->va_start && addr + size <= vend) { - addr = ALIGN(first->va_end + PAGE_SIZE, align); + addr = ALIGN(first->va_end, align); n = rb_next(&first->rb_node); if (n) @@ -954,7 +959,7 @@ void unmap_kernel_range(unsigned long addr, unsigned long size) int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages) { unsigned long addr = (unsigned long)area->addr; - unsigned long end = addr + area->size - PAGE_SIZE; + unsigned long end = addr + area->size - GUARD_PAGE_SIZE; int err; err = vmap_page_range(addr, end, prot, *pages); @@ -1003,7 +1008,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, /* * We always allocate a guard page. */ - size += PAGE_SIZE; + size += GUARD_PAGE_SIZE; va = alloc_vmap_area(size, align, start, end, node, gfp_mask); if (IS_ERR(va)) { @@ -1098,7 +1103,7 @@ struct vm_struct *remove_vm_area(const void *addr) struct vm_struct *vm = va->private; struct vm_struct *tmp, **p; free_unmap_vmap_area(va); - vm->size -= PAGE_SIZE; + vm->size -= GUARD_PAGE_SIZE; write_lock(&vmlist_lock); for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next) @@ -1226,7 +1231,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, struct page **pages; unsigned int nr_pages, array_size, i; - nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT; + nr_pages = (area->size - GUARD_PAGE_SIZE) >> PAGE_SHIFT; array_size = (nr_pages * sizeof(struct page *)); area->nr_pages = nr_pages; @@ -1451,7 +1456,7 @@ long vread(char *buf, char *addr, unsigned long count) read_lock(&vmlist_lock); for (tmp = vmlist; tmp; tmp = tmp->next) { vaddr = (char *) tmp->addr; - if (addr >= vaddr + tmp->size - PAGE_SIZE) + if (addr >= vaddr + tmp->size - GUARD_PAGE_SIZE) continue; while (addr < vaddr) { if (count == 0) @@ -1461,7 +1466,7 @@ long vread(char *buf, char *addr, unsigned long count) addr++; count--; } - n = vaddr + tmp->size - PAGE_SIZE - addr; + n = vaddr + tmp->size - GUARD_PAGE_SIZE - addr; do { if (count == 0) goto finished; @@ -1489,7 +1494,7 @@ long vwrite(char *buf, char *addr, unsigned long count) read_lock(&vmlist_lock); for (tmp = vmlist; tmp; tmp = tmp->next) { vaddr = (char *) tmp->addr; - if (addr >= vaddr + tmp->size - PAGE_SIZE) + if (addr >= vaddr + tmp->size - GUARD_PAGE_SIZE) continue; while (addr < vaddr) { if (count == 0) @@ -1498,7 +1503,7 @@ long vwrite(char *buf, char *addr, unsigned long count) addr++; count--; } - n = vaddr + tmp->size - PAGE_SIZE - addr; + n = vaddr + tmp->size - GUARD_PAGE_SIZE - addr; do { if (count == 0) goto finished; @@ -1544,7 +1549,7 @@ int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, if (!(area->flags & VM_USERMAP)) return -EINVAL; - if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE) + if (usize + (pgoff << PAGE_SHIFT) > area->size - GUARD_PAGE_SIZE) return -EINVAL; addr += pgoff << PAGE_SHIFT; -- 1.5.6.5
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