linux.git/mm/vmalloc.c, branch v3.15

mm/vmalloc.c: enhance vm_map_ram() comment

2014-04-07T23:35:55+00:00

vm_map_ram() has a fragmentation problem when it cannot purge a
chunk(ie, 4M address space) if there is a pinning object in that
addresss space.  So it could consume all VMALLOC address space easily.

We can fix the fragmentation problem by using vmap instead of
vm_map_ram() but vmap() is known to be slow compared to vm_map_ram().
Minchan said vm_map_ram is 5 times faster than vmap in his tests.  So I
thought we should fix fragment problem of vm_map_ram because our
proprietary GPU driver has used it heavily.

On second thought, it's not an easy because we should reuse freed space
for solving the problem and it could make more IPI and bitmap operation
for searching hole.  It could mitigate API's goal which is very fast
mapping.  And even fragmentation problem wouldn't show in 64 bit
machine.

Another option is that the user should separate long-life and short-life
object and use vmap for long-life but vm_map_ram for short-life.  If we
inform the user about the characteristic of vm_map_ram the user can
choose one according to the page lifetime.

Let's add some notice messages to user.

[akpm@linux-foundation.org: tweak comment text]
Signed-off-by: Gioh Kim 
Reviewed-by: Zhang Yanfei 
Cc: Minchan Kim 
Cc: Johannes Weiner 
Cc: Joonsoo Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: use macros from compiler.h instead of attribute((...))

2014-04-07T23:35:54+00:00

To increase compiler portability there is  which
provides convenience macros for various gcc constructs.  Eg: __weak for
__attribute__((weak)).  I've replaced all instances of gcc attributes with
the right macro in the memory management (/mm) subsystem.

[akpm@linux-foundation.org: while-we're-there consistency tweaks]
Signed-off-by: Gideon Israel Dsouza 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Revert "mm/vmalloc: interchage the implementation of vmalloc_to_{pfn,page}"

2014-01-28T05:02:39+00:00

Revert commit ece86e222db4, which was intended as a small performance
improvement.

Despite the claim that the patch doesn't introduce any functional
changes in fact it does.

The "no page" path behaves different now.  Originally, vmalloc_to_page
might return NULL under some conditions, with new implementation it
returns pfn_to_page(0) which is not the same as NULL.

Simple test shows the difference.

test.c

#include 
#include 
#include 
#include 

int __init myi(void)
{
	struct page *p;
	void *v;

	v = vmalloc(PAGE_SIZE);
	/* trigger the "no page" path in vmalloc_to_page*/
	vfree(v);

	p = vmalloc_to_page(v);

	pr_err("expected val = NULL, returned val = %p", p);

	return -EBUSY;
}

void __exit mye(void)
{

}
module_init(myi)
module_exit(mye)

Before interchange:
expected val = NULL, returned val =   (null)

After interchange:
expected val = NULL, returned val = c7ebe000

Signed-off-by: Vladimir Murzin 
Cc: Jianyu Zhan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: interchage the implementation of vmalloc_to_{pfn,page}

2014-01-22T00:19:44+00:00

Currently we are implementing vmalloc_to_pfn() as a wrapper around
vmalloc_to_page(), which is implemented as follow:

 1. walks the page talbes to generates the corresponding pfn,
 2. then converts the pfn to struct page,
 3. returns it.

And vmalloc_to_pfn() re-wraps vmalloc_to_page() to get the pfn.

This seems too circuitous, so this patch reverses the way: implement
vmalloc_to_page() as a wrapper around vmalloc_to_pfn().  This makes
vmalloc_to_pfn() and vmalloc_to_page() slightly more efficient.

No functional change.

Signed-off-by: Jianyu Zhan 
Cc: Vladimir Murzin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: kmemleak: avoid false negatives on vmalloc'ed objects

2013-11-13T03:09:07+00:00

Commit 248ac0e1943a ("mm/vmalloc: remove guard page from between vmap
blocks") had the side effect of making vmap_area.va_end member point to
the next vmap_area.va_start.  This was creating an artificial reference
to vmalloc'ed objects and kmemleak was rarely reporting vmalloc() leaks.

This patch marks the vmap_area containing pointers explicitly and
reduces the min ref_count to 2 as vm_struct still contains a reference
to the vmalloc'ed object.  The kmemleak add_scan_area() function has
been improved to allow a SIZE_MAX argument covering the rest of the
object (for simpler calling sites).

Signed-off-by: Catalin Marinas 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

revert mm/vmalloc.c: emit the failure message before return

2013-11-13T03:09:05+00:00

Don't warn twice in __vmalloc_area_node and __vmalloc_node_range if
__vmalloc_area_node allocation failure.  This patch reverts commit
46c001a2753f ("mm/vmalloc.c: emit the failure message before return").

Signed-off-by: Wanpeng Li 
Reviewed-by: Zhang Yanfei 
Cc: Joonsoo Kim 
Cc: KOSAKI Motohiro 
Cc: Mitsuo Hayasaka 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: revert "mm/vmalloc.c: check VM_UNINITIALIZED flag in s_show instead of show_numa_info"

2013-11-13T03:09:05+00:00

The VM_UNINITIALIZED/VM_UNLIST flag introduced by f5252e009d5b ("mm:
avoid null pointer access in vm_struct via /proc/vmallocinfo") is used
to avoid accessing the pages field with unallocated page when
show_numa_info() is called.

This patch moves the check just before show_numa_info in order that some
messages still can be dumped via /proc/vmallocinfo.  This patch reverts
commit d157a55815ff ("mm/vmalloc.c: check VM_UNINITIALIZED flag in
s_show instead of show_numa_info");

Reviewed-by: Zhang Yanfei 
Signed-off-by: Wanpeng Li 
Cc: Mitsuo Hayasaka 
Cc: Joonsoo Kim 
Cc: KOSAKI Motohiro 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: fix show vmap_area information race with vmap_area tear down

2013-11-13T03:09:05+00:00

There is a race window between vmap_area tear down and show vmap_area
information.

	A                                                B

remove_vm_area
spin_lock(&vmap_area_lock);
va->vm = NULL;
va->flags &= ~VM_VM_AREA;
spin_unlock(&vmap_area_lock);
						spin_lock(&vmap_area_lock);
						if (va->flags & (VM_LAZY_FREE | VM_LAZY_FREEZING))
							return 0;
						if (!(va->flags & VM_VM_AREA)) {
							seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
								(void *)va->va_start, (void *)va->va_end,
								va->va_end - va->va_start);
							return 0;
						}
free_unmap_vmap_area(va);
	flush_cache_vunmap
	free_unmap_vmap_area_noflush
		unmap_vmap_area
		free_vmap_area_noflush
			va->flags |= VM_LAZY_FREE

The assumption !VM_VM_AREA represents vm_map_ram allocation is
introduced by d4033afdf828 ("mm, vmalloc: iterate vmap_area_list,
instead of vmlist, in vmallocinfo()").

However, !VM_VM_AREA also represents vmap_area is being tear down in
race window mentioned above.  This patch fix it by don't dump any
information for !VM_VM_AREA case and also remove (VM_LAZY_FREE |
VM_LAZY_FREEING) check since they are not possible for !VM_VM_AREA case.

Suggested-by: Joonsoo Kim 
Acked-by: KOSAKI Motohiro 
Signed-off-by: Wanpeng Li 
Cc: Mitsuo Hayasaka 
Cc: Zhang Yanfei 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: don't set area->caller twice

2013-11-13T03:09:05+00:00

The caller address has already been set in set_vmalloc_vm(), there's no
need to set it again in __vmalloc_area_node.

Reviewed-by: Zhang Yanfei 
Signed-off-by: Wanpeng Li 
Cc: Joonsoo Kim 
Cc: KOSAKI Motohiro 
Cc: Mitsuo Hayasaka 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: use NUMA_NO_NODE

2013-11-13T03:09:02+00:00

Use more appropriate "if (node == NUMA_NO_NODE)" instead of "if (node < 0)"

Signed-off-by: Jianguo Wu 
Acked-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

linux.git/mm/vmalloc.c, branch v3.15

mm/vmalloc.c: enhance vm_map_ram() comment

mm: use macros from compiler.h instead of __attribute__((...))

Revert "mm/vmalloc: interchage the implementation of vmalloc_to_{pfn,page}"

mm/vmalloc: interchage the implementation of vmalloc_to_{pfn,page}

mm: kmemleak: avoid false negatives on vmalloc'ed objects

revert mm/vmalloc.c: emit the failure message before return

mm/vmalloc: revert "mm/vmalloc.c: check VM_UNINITIALIZED flag in s_show instead of show_numa_info"

mm/vmalloc: fix show vmap_area information race with vmap_area tear down

mm/vmalloc: don't set area->caller twice

mm/vmalloc: use NUMA_NO_NODE

mm: use macros from compiler.h instead of attribute((...))