Commit 78c72746 authored Jul 10, 2017 by Yisheng Xie Committed by Linus Torvalds Jul 10, 2017

vmalloc: show lazy-purged vma info in vmallocinfo

When ioremap a 67112960 bytes vm_area with the vmallocinfo:
 [..]
 0xec79b000-0xec7fa000  389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc
 0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap

we get the result:
 0xf1000000-0xf5001000 67112960 devm_ioremap+0x38/0x7c phys=40000000 ioremap

For the align for ioremap must be less than '1 << IOREMAP_MAX_ORDER':

	if (flags & VM_IOREMAP)
		align = 1ul << clamp_t(int, get_count_order_long(size),
			PAGE_SHIFT, IOREMAP_MAX_ORDER);

So it makes idiot like me a litte puzzled why this was a jump the
vm_area from 0xec800000-0xecbe1000 to 0xf1000000-0xf5001000, and leaving
0xed000000-0xf1000000 as a big hole.

This patch is to show all of vm_area, including vmas which are freeing
but still in the vmap_area_list, to make it more clear about why we will
get 0xf1000000-0xf5001000 in the above case.  And we will get a
vmallocinfo like:

 [..]
 0xec79b000-0xec7fa000  389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc
 0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap
 [..]
 0xece7c000-0xece7e000    8192 unpurged vm_area
 0xece7e000-0xece83000   20480 vm_map_ram
 0xf0099000-0xf00aa000   69632 vm_map_ram

after this patch.

Link: http://lkml.kernel.org/r/1496649682-20710-1-git-send-email-xieyisheng1@huawei.com


Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: zijun_hu <zijun_hu@htc.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 34c81057

mm/vmalloc.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -325,6 +325,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn);

		/* Global kva allocator */

		#define VM_LAZY_FREE 0x02
		#define VM_VM_AREA 0x04

		static DEFINE_SPINLOCK(vmap_area_lock);
		@@ -1497,6 +1498,7 @@ struct vm_struct remove_vm_area(const void addr)
		spin_lock(&vmap_area_lock);
		va->vm = NULL;
		va->flags &= ~VM_VM_AREA;
		va->flags \|= VM_LAZY_FREE;
		spin_unlock(&vmap_area_lock);

		vmap_debug_free_range(va->va_start, va->va_end);
		@@ -2704,8 +2706,14 @@ static int s_show(struct seq_file m, void p)
		* s_show can encounter race with remove_vm_area, !VM_VM_AREA on
		* behalf of vmap area is being tear down or vm_map_ram allocation.
		*/
		if (!(va->flags & VM_VM_AREA))
		if (!(va->flags & VM_VM_AREA)) {
		seq_printf(m, "0x%pK-0x%pK %7ld %s\n",
		(void )va->va_start, (void )va->va_end,
		va->va_end - va->va_start,
		va->flags & VM_LAZY_FREE ? "unpurged vm_area" : "vm_map_ram");

		return 0;
		}

		v = va->vm;

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