[PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[Zhaoyang Huang]

/proc/vmallocinfo will not show the area allocated by vm_map_ram, which
will make confusion when debug. Add vm_struct for them and show them in
proc.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@spreadtrum.com>
---
 mm/vmalloc.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 34a1c3e..4a2e93c 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -46,6 +46,9 @@ struct vfree_deferred {
 
 static void __vunmap(const void *, int);
 
+static void setup_vmap_ram_vm(struct vm_struct *vm, struct vmap_area *va,
+				unsigned long flags, const void *caller);
+
 static void free_work(struct work_struct *w)
 {
 	struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
@@ -315,6 +318,7 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
 /*** Global kva allocator ***/
 
 #define VM_VM_AREA	0x04
+#define VM_VM_RAM	0x08
 
 static DEFINE_SPINLOCK(vmap_area_lock);
 /* Export for kexec only */
@@ -1141,6 +1145,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
 
 	va = find_vmap_area(addr);
 	BUG_ON(!va);
+	kfree(va->vm);
 	free_unmap_vmap_area(va);
 }
 EXPORT_SYMBOL(vm_unmap_ram);
@@ -1173,6 +1178,12 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
 		addr = (unsigned long)mem;
 	} else {
 		struct vmap_area *va;
+		struct vm_struct *area;
+
+		area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
+		if (unlikely(!area))
+			return NULL;
+
 		va = alloc_vmap_area(size, PAGE_SIZE,
 				VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
 		if (IS_ERR(va))
@@ -1180,6 +1191,7 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
 
 		addr = va->va_start;
 		mem = (void *)addr;
+		setup_vmap_ram_vm(area, va, 0, __builtin_return_address(0));
 	}
 	if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
 		vm_unmap_ram(mem, count);
@@ -1362,6 +1374,19 @@ static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
 	spin_unlock(&vmap_area_lock);
 }
 
+static void setup_vmap_ram_vm(struct vm_struct *vm, struct vmap_area *va,
+			      unsigned long flags, const void *caller)
+{
+	spin_lock(&vmap_area_lock);
+	vm->flags = flags;
+	vm->addr = (void *)va->va_start;
+	vm->size = va->va_end - va->va_start;
+	vm->caller = caller;
+	va->vm = vm;
+	va->flags |= VM_VM_RAM;
+	spin_unlock(&vmap_area_lock);
+}
+
 static void clear_vm_uninitialized_flag(struct vm_struct *vm)
 {
 	/*
@@ -2698,7 +2723,7 @@ 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 | VM_VM_RAM)))
 		return 0;
 
 	v = va->vm;
-- 
1.9.1

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Re: [PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[Andrew Morton]

On Wed, 19 Jul 2017 18:44:03 +0800 Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:

> /proc/vmallocinfo will not show the area allocated by vm_map_ram, which
> will make confusion when debug. Add vm_struct for them and show them in
> proc.
> 

Please provide sample /proc/vmallocinfo so we can better understand the
proposal.  Is there a means by which people can determine that a
particular area is from vm_map_ram()?  I don't think so.  Should there
be?

>
> ...
>
> @@ -1173,6 +1178,12 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>  		addr = (unsigned long)mem;
>  	} else {
>  		struct vmap_area *va;
> +		struct vm_struct *area;
> +
> +		area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
> +		if (unlikely(!area))
> +			return NULL;

Allocating a vm_struct for each vm_map_ram area is a cost.  And we're
doing this purely for /proc/vmallocinfo.  I think I'll need more
persuading to convince me that this is a good tradeoff, given that
*every* user will incur this cost, and approximately 0% of them will
ever use /proc/vmallocinfo.

So... do we *really* need this?  If so, why?

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Re: [PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[Zhaoyang Huang]

On Thu, Jul 20, 2017 at 4:50 AM, Andrew Morton
<akpm@linux-foundation.org> wrote:
> On Wed, 19 Jul 2017 18:44:03 +0800 Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:
>
>> /proc/vmallocinfo will not show the area allocated by vm_map_ram, which
>> will make confusion when debug. Add vm_struct for them and show them in
>> proc.
>>
>
> Please provide sample /proc/vmallocinfo so we can better understand the
> proposal.  Is there a means by which people can determine that a
> particular area is from vm_map_ram()?  I don't think so.  Should there
> be?
Here is the part of vmallocinfo, the line start with '>' are the ones
allocated by vm_map_ram.
xxxx:/ # cat /proc/vmallocinfo
0xffffff8000a5f000-0xffffff8000abb000  376832
load_module+0x1004/0x1e98 pages=91 vmalloc
0xffffff8000ac6000-0xffffff8000ad2000   49152
load_module+0x1004/0x1e98 pages=11 vmalloc
0xffffff8000ad8000-0xffffff8000ade000   24576
load_module+0x1004/0x1e98 pages=5 vmalloc
0xffffff8008000000-0xffffff8008002000    8192 of_iomap+0x4c/0x68
phys=12001000 ioremap
0xffffff8008002000-0xffffff8008004000    8192 of_iomap+0x4c/0x68
phys=40356000 ioremap
0xffffff8008004000-0xffffff8008007000   12288 of_iomap+0x4c/0x68
phys=12002000 ioremap
0xffffff8008008000-0xffffff800800d000   20480
of_sprd_gates_clk_setup_with_ops+0x88/0x2a8 phys=402b0000 ioremap
0xffffff800800e000-0xffffff8008010000    8192 of_iomap+0x4c/0x68
phys=40356000 ioremap
...
>0xffffff800c5a3000-0xffffff800c5ec000  299008 shmem_ram_vmap+0xe8/0x1a0
0xffffff800c5fe000-0xffffff800c600000    8192
kbasep_js_policy_ctx_has_priority+0x254/0xdb0 [mali_kbase] pages=1
vmalloc
0xffffff800c600000-0xffffff800c701000 1052672 of_iomap+0x4c/0x68
phys=60d00000 ioremap
>0xffffff800c701000-0xffffff800c742000  266240 shmem_ram_vmap+0xe8/0x1a0
0xffffff800c74e000-0xffffff800c750000    8192
kbasep_js_policy_ctx_has_priority+0x2cc/0xdb0 [mali_kbase] pages=1
vmalloc
...
>
>>
>> ...
>>
>> @@ -1173,6 +1178,12 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>>               addr = (unsigned long)mem;
>>       } else {
>>               struct vmap_area *va;
>> +             struct vm_struct *area;
>> +
>> +             area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
>> +             if (unlikely(!area))
>> +                     return NULL;
>
> Allocating a vm_struct for each vm_map_ram area is a cost.  And we're
> doing this purely for /proc/vmallocinfo.  I think I'll need more
> persuading to convince me that this is a good tradeoff, given that
> *every* user will incur this cost, and approximately 0% of them will
> ever use /proc/vmallocinfo.
>
> So... do we *really* need this?  If so, why?
The motivation of this commit comes from one practical debug, that is,
vmalloc failed by one driver's allocating a
huge area by vm_map_ram, which can not be traced by cat
/proc/vmallocinfo. We have to add a lot of printk and
dump_stack to get more information.
I don't think the vm_struct cost too much memory, just imagine that
the area got by vmalloc or ioremap instead, you have
to pay for it as well.
>

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Re: [PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[Zhaoyang Huang]

update the comment bellow as ...'s/by one driver's allocating/because
one driver has allocated/'..., sorry
for the confusion


On Thu, Jul 20, 2017 at 9:15 AM, Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:
> On Thu, Jul 20, 2017 at 4:50 AM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
>> On Wed, 19 Jul 2017 18:44:03 +0800 Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:
>>
>>> /proc/vmallocinfo will not show the area allocated by vm_map_ram, which
>>> will make confusion when debug. Add vm_struct for them and show them in
>>> proc.
>>>
>>
>> Please provide sample /proc/vmallocinfo so we can better understand the
>> proposal.  Is there a means by which people can determine that a
>> particular area is from vm_map_ram()?  I don't think so.  Should there
>> be?
> Here is the part of vmallocinfo, the line start with '>' are the ones
> allocated by vm_map_ram.
> xxxx:/ # cat /proc/vmallocinfo
> 0xffffff8000a5f000-0xffffff8000abb000  376832
> load_module+0x1004/0x1e98 pages=91 vmalloc
> 0xffffff8000ac6000-0xffffff8000ad2000   49152
> load_module+0x1004/0x1e98 pages=11 vmalloc
> 0xffffff8000ad8000-0xffffff8000ade000   24576
> load_module+0x1004/0x1e98 pages=5 vmalloc
> 0xffffff8008000000-0xffffff8008002000    8192 of_iomap+0x4c/0x68
> phys=12001000 ioremap
> 0xffffff8008002000-0xffffff8008004000    8192 of_iomap+0x4c/0x68
> phys=40356000 ioremap
> 0xffffff8008004000-0xffffff8008007000   12288 of_iomap+0x4c/0x68
> phys=12002000 ioremap
> 0xffffff8008008000-0xffffff800800d000   20480
> of_sprd_gates_clk_setup_with_ops+0x88/0x2a8 phys=402b0000 ioremap
> 0xffffff800800e000-0xffffff8008010000    8192 of_iomap+0x4c/0x68
> phys=40356000 ioremap
> ...
>>0xffffff800c5a3000-0xffffff800c5ec000  299008 shmem_ram_vmap+0xe8/0x1a0
> 0xffffff800c5fe000-0xffffff800c600000    8192
> kbasep_js_policy_ctx_has_priority+0x254/0xdb0 [mali_kbase] pages=1
> vmalloc
> 0xffffff800c600000-0xffffff800c701000 1052672 of_iomap+0x4c/0x68
> phys=60d00000 ioremap
>>0xffffff800c701000-0xffffff800c742000  266240 shmem_ram_vmap+0xe8/0x1a0
> 0xffffff800c74e000-0xffffff800c750000    8192
> kbasep_js_policy_ctx_has_priority+0x2cc/0xdb0 [mali_kbase] pages=1
> vmalloc
> ...
>>
>>>
>>> ...
>>>
>>> @@ -1173,6 +1178,12 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>>>               addr = (unsigned long)mem;
>>>       } else {
>>>               struct vmap_area *va;
>>> +             struct vm_struct *area;
>>> +
>>> +             area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
>>> +             if (unlikely(!area))
>>> +                     return NULL;
>>
>> Allocating a vm_struct for each vm_map_ram area is a cost.  And we're
>> doing this purely for /proc/vmallocinfo.  I think I'll need more
>> persuading to convince me that this is a good tradeoff, given that
>> *every* user will incur this cost, and approximately 0% of them will
>> ever use /proc/vmallocinfo.
>>
>> So... do we *really* need this?  If so, why?
> The motivation of this commit comes from one practical debug, that is,
> vmalloc failed 's/by one driver's allocating/because one driver has allocated/' a
> huge area by vm_map_ram, which can not be traced by cat
> /proc/vmallocinfo. We have to add a lot of printk and
> dump_stack to get more information.
> I don't think the vm_struct cost too much memory, just imagine that
> the area got by vmalloc or ioremap instead, you have
> to pay for it as well.
>>

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Re: [PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[zijun_hu]

On 07/19/2017 06:44 PM, Zhaoyang Huang wrote:
> /proc/vmallocinfo will not show the area allocated by vm_map_ram, which
> will make confusion when debug. Add vm_struct for them and show them in
> proc.
> 
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@spreadtrum.com>
> ---
another patch titled "vmalloc: show lazy-purged vma info in vmallocinfo" was phased-in to linux-next branch
to resolve this problem.
>  mm/vmalloc.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 34a1c3e..4a2e93c 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -46,6 +46,9 @@ struct vfree_deferred {
>  
>  static void __vunmap(const void *, int);
>  
> +static void setup_vmap_ram_vm(struct vm_struct *vm, struct vmap_area *va,
> +				unsigned long flags, const void *caller);
> +
>  static void free_work(struct work_struct *w)
>  {
>  	struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
> @@ -315,6 +318,7 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
>  /*** Global kva allocator ***/
>  
>  #define VM_VM_AREA	0x04
> +#define VM_VM_RAM	0x08
>  
>  static DEFINE_SPINLOCK(vmap_area_lock);
>  /* Export for kexec only */
> @@ -1141,6 +1145,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
>  
>  	va = find_vmap_area(addr);
>  	BUG_ON(!va);
> +	kfree(va->vm);
>  	free_unmap_vmap_area(va);
>  }
>  EXPORT_SYMBOL(vm_unmap_ram);
> @@ -1173,6 +1178,12 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>  		addr = (unsigned long)mem;
>  	} else {
>  		struct vmap_area *va;
> +		struct vm_struct *area;
> +
> +		area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
> +		if (unlikely(!area))
> +			return NULL;
> +
>  		va = alloc_vmap_area(size, PAGE_SIZE,
>  				VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
>  		if (IS_ERR(va))
> @@ -1180,6 +1191,7 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>  
>  		addr = va->va_start;
>  		mem = (void *)addr;
> +		setup_vmap_ram_vm(area, va, 0, __builtin_return_address(0));
>  	}
>  	if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
>  		vm_unmap_ram(mem, count);
> @@ -1362,6 +1374,19 @@ static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
>  	spin_unlock(&vmap_area_lock);
>  }
>  
> +static void setup_vmap_ram_vm(struct vm_struct *vm, struct vmap_area *va,
> +			      unsigned long flags, const void *caller)
> +{
> +	spin_lock(&vmap_area_lock);
> +	vm->flags = flags;
> +	vm->addr = (void *)va->va_start;
> +	vm->size = va->va_end - va->va_start;
> +	vm->caller = caller;
> +	va->vm = vm;
> +	va->flags |= VM_VM_RAM;
> +	spin_unlock(&vmap_area_lock);
> +}
> +
>  static void clear_vm_uninitialized_flag(struct vm_struct *vm)
>  {
>  	/*
> @@ -2698,7 +2723,7 @@ 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 | VM_VM_RAM)))
>  		return 0;
>  
>  	v = va->vm;
> 


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