[PATCH v6 0/2] mm/vmalloc.c: improve readability and rewrite vmap_area

[PATCH v6 0/2] mm/vmalloc.c: improve readability and rewrite vmap_area

[Pengfei Li]

v5 -> v6
* patch 2: keep the comment in s_show()

v4 -> v5
* Base on next-20190716
* patch 1: From Uladzislau Rezki (Sony) <urezki@gmail.com> (author)
  - https://lkml.org/lkml/2019/7/16/276
* patch 2: Use v3

v3 -> v4:
* Base on next-20190711
* patch 1: From: Uladzislau Rezki (Sony) <urezki@gmail.com> (author)
  - https://lkml.org/lkml/2019/7/3/661
* patch 2: Modify the layout of struct vmap_area for readability

v2 -> v3:
* patch 1-4: Abandoned
* patch 5:
  - Eliminate "flags" (suggested by Uladzislau Rezki)
  - Base on https://lkml.org/lkml/2019/6/6/455
    and https://lkml.org/lkml/2019/7/3/661

v1 -> v2:
* patch 3: Rename __find_vmap_area to __search_va_in_busy_tree
           instead of __search_va_from_busy_tree.
* patch 5: Add motivation and necessary test data to the commit
           message.
* patch 5: Let va->flags use only some low bits of va_start
           instead of completely overwriting va_start.

The current implementation of struct vmap_area wasted space.

After applying this commit, sizeof(struct vmap_area) has been
reduced from 11 words to 8 words.

Pengfei Li (1):
  mm/vmalloc: modify struct vmap_area to reduce its size

Uladzislau Rezki (Sony) (1):
  mm/vmalloc: do not keep unpurged areas in the busy tree

 include/linux/vmalloc.h | 20 +++++++----
 mm/vmalloc.c            | 76 +++++++++++++++++++++++++++++------------
 2 files changed, 67 insertions(+), 29 deletions(-)

-- 
2.21.0

[PATCH v6 1/2] mm/vmalloc: do not keep unpurged areas in the busy tree

[Pengfei Li]

From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>

The busy tree can be quite big, even though the area is freed
or unmapped it still stays there until "purge" logic removes
it.

1) Optimize and reduce the size of "busy" tree by removing a
node from it right away as soon as user triggers free paths.
It is possible to do so, because the allocation is done using
another augmented tree.

The vmalloc test driver shows the difference, for example the
"fix_size_alloc_test" is ~11% better comparing with default
configuration:

sudo ./test_vmalloc.sh performance

<default>
Summary: fix_size_alloc_test loops: 1000000 avg: 993985 usec
Summary: full_fit_alloc_test loops: 1000000 avg: 973554 usec
Summary: long_busy_list_alloc_test loops: 1000000 avg: 12617652 usec
<default>

<this patch>
Summary: fix_size_alloc_test loops: 1000000 avg: 882263 usec
Summary: full_fit_alloc_test loops: 1000000 avg: 973407 usec
Summary: long_busy_list_alloc_test loops: 1000000 avg: 12593929 usec
<this patch>

2) Since the busy tree now contains allocated areas only and does
not interfere with lazily free nodes, introduce the new function
show_purge_info() that dumps "unpurged" areas that is propagated
through "/proc/vmallocinfo".

3) Eliminate VM_LAZY_FREE flag.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
 mm/vmalloc.c | 52 ++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 8 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 4fa8d84599b0..71d8040a8a0b 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -329,7 +329,6 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 #define DEBUG_AUGMENT_PROPAGATE_CHECK 0
 #define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
 
-#define VM_LAZY_FREE	0x02
 #define VM_VM_AREA	0x04
 
 static DEFINE_SPINLOCK(vmap_area_lock);
@@ -1276,7 +1275,14 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
 	llist_for_each_entry_safe(va, n_va, valist, purge_list) {
 		unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
 
-		__free_vmap_area(va);
+		/*
+		 * Finally insert or merge lazily-freed area. It is
+		 * detached and there is no need to "unlink" it from
+		 * anything.
+		 */
+		merge_or_add_vmap_area(va,
+			&free_vmap_area_root, &free_vmap_area_list);
+
 		atomic_long_sub(nr, &vmap_lazy_nr);
 
 		if (atomic_long_read(&vmap_lazy_nr) < resched_threshold)
@@ -1318,6 +1324,10 @@ static void free_vmap_area_noflush(struct vmap_area *va)
 {
 	unsigned long nr_lazy;
 
+	spin_lock(&vmap_area_lock);
+	unlink_va(va, &vmap_area_root);
+	spin_unlock(&vmap_area_lock);
+
 	nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
 				PAGE_SHIFT, &vmap_lazy_nr);
 
@@ -2137,14 +2147,13 @@ struct vm_struct *remove_vm_area(const void *addr)
 
 	might_sleep();
 
-	va = find_vmap_area((unsigned long)addr);
+	spin_lock(&vmap_area_lock);
+	va = __find_vmap_area((unsigned long)addr);
 	if (va && va->flags & VM_VM_AREA) {
 		struct vm_struct *vm = va->vm;
 
-		spin_lock(&vmap_area_lock);
 		va->vm = NULL;
 		va->flags &= ~VM_VM_AREA;
-		va->flags |= VM_LAZY_FREE;
 		spin_unlock(&vmap_area_lock);
 
 		kasan_free_shadow(vm);
@@ -2152,6 +2161,8 @@ struct vm_struct *remove_vm_area(const void *addr)
 
 		return vm;
 	}
+
+	spin_unlock(&vmap_area_lock);
 	return NULL;
 }
 
@@ -3431,6 +3442,22 @@ static void show_numa_info(struct seq_file *m, struct vm_struct *v)
 	}
 }
 
+static void show_purge_info(struct seq_file *m)
+{
+	struct llist_node *head;
+	struct vmap_area *va;
+
+	head = READ_ONCE(vmap_purge_list.first);
+	if (head == NULL)
+		return;
+
+	llist_for_each_entry(va, head, purge_list) {
+		seq_printf(m, "0x%pK-0x%pK %7ld unpurged vm_area\n",
+			(void *)va->va_start, (void *)va->va_end,
+			va->va_end - va->va_start);
+	}
+}
+
 static int s_show(struct seq_file *m, void *p)
 {
 	struct vmap_area *va;
@@ -3443,10 +3470,9 @@ static int s_show(struct seq_file *m, void *p)
 	 * behalf of vmap area is being tear down or vm_map_ram allocation.
 	 */
 	if (!(va->flags & VM_VM_AREA)) {
-		seq_printf(m, "0x%pK-0x%pK %7ld %s\n",
+		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,
-			va->flags & VM_LAZY_FREE ? "unpurged vm_area" : "vm_map_ram");
+			va->va_end - va->va_start);
 
 		return 0;
 	}
@@ -3482,6 +3508,16 @@ static int s_show(struct seq_file *m, void *p)
 
 	show_numa_info(m, v);
 	seq_putc(m, '\n');
+
+	/*
+	 * As a final step, dump "unpurged" areas. Note,
+	 * that entire "/proc/vmallocinfo" output will not
+	 * be address sorted, because the purge list is not
+	 * sorted.
+	 */
+	if (list_is_last(&va->list, &vmap_area_list))
+		show_purge_info(m);
+
 	return 0;
 }
 
-- 
2.21.0

[PATCH v6 2/2] mm/vmalloc: modify struct vmap_area to reduce its size

[Pengfei Li]

Objective
---------
The current implementation of struct vmap_area wasted space.

After applying this commit, sizeof(struct vmap_area) has been
reduced from 11 words to 8 words.

Description
-----------
1) Pack "subtree_max_size", "vm" and "purge_list".
This is no problem because
    A) "subtree_max_size" is only used when vmap_area is in
       "free" tree
    B) "vm" is only used when vmap_area is in "busy" tree
    C) "purge_list" is only used when vmap_area is in
       vmap_purge_list

2) Eliminate "flags".
Since only one flag VM_VM_AREA is being used, and the same
thing can be done by judging whether "vm" is NULL, then the
"flags" can be eliminated.

Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Suggested-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
 include/linux/vmalloc.h | 20 +++++++++++++-------
 mm/vmalloc.c            | 24 ++++++++++--------------
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 9b21d0047710..a1334bd18ef1 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -51,15 +51,21 @@ struct vmap_area {
 	unsigned long va_start;
 	unsigned long va_end;
 
-	/*
-	 * Largest available free size in subtree.
-	 */
-	unsigned long subtree_max_size;
-	unsigned long flags;
 	struct rb_node rb_node;         /* address sorted rbtree */
 	struct list_head list;          /* address sorted list */
-	struct llist_node purge_list;    /* "lazy purge" list */
-	struct vm_struct *vm;
+
+	/*
+	 * The following three variables can be packed, because
+	 * a vmap_area object is always one of the three states:
+	 *    1) in "free" tree (root is vmap_area_root)
+	 *    2) in "busy" tree (root is free_vmap_area_root)
+	 *    3) in purge list  (head is vmap_purge_list)
+	 */
+	union {
+		unsigned long subtree_max_size; /* in "free" tree */
+		struct vm_struct *vm;           /* in "busy" tree */
+		struct llist_node purge_list;   /* in purge list */
+	};
 };
 
 /*
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 71d8040a8a0b..2f7edc0466e7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -329,7 +329,6 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 #define DEBUG_AUGMENT_PROPAGATE_CHECK 0
 #define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
 
-#define VM_VM_AREA	0x04
 
 static DEFINE_SPINLOCK(vmap_area_lock);
 /* Export for kexec only */
@@ -1115,7 +1114,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 
 	va->va_start = addr;
 	va->va_end = addr + size;
-	va->flags = 0;
+	va->vm = NULL;
 	insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
 
 	spin_unlock(&vmap_area_lock);
@@ -1922,7 +1921,6 @@ void __init vmalloc_init(void)
 		if (WARN_ON_ONCE(!va))
 			continue;
 
-		va->flags = VM_VM_AREA;
 		va->va_start = (unsigned long)tmp->addr;
 		va->va_end = va->va_start + tmp->size;
 		va->vm = tmp;
@@ -2020,7 +2018,6 @@ static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
 	vm->size = va->va_end - va->va_start;
 	vm->caller = caller;
 	va->vm = vm;
-	va->flags |= VM_VM_AREA;
 	spin_unlock(&vmap_area_lock);
 }
 
@@ -2125,10 +2122,10 @@ struct vm_struct *find_vm_area(const void *addr)
 	struct vmap_area *va;
 
 	va = find_vmap_area((unsigned long)addr);
-	if (va && va->flags & VM_VM_AREA)
-		return va->vm;
+	if (!va)
+		return NULL;
 
-	return NULL;
+	return va->vm;
 }
 
 /**
@@ -2149,11 +2146,10 @@ struct vm_struct *remove_vm_area(const void *addr)
 
 	spin_lock(&vmap_area_lock);
 	va = __find_vmap_area((unsigned long)addr);
-	if (va && va->flags & VM_VM_AREA) {
+	if (va && va->vm) {
 		struct vm_struct *vm = va->vm;
 
 		va->vm = NULL;
-		va->flags &= ~VM_VM_AREA;
 		spin_unlock(&vmap_area_lock);
 
 		kasan_free_shadow(vm);
@@ -2856,7 +2852,7 @@ long vread(char *buf, char *addr, unsigned long count)
 		if (!count)
 			break;
 
-		if (!(va->flags & VM_VM_AREA))
+		if (!va->vm)
 			continue;
 
 		vm = va->vm;
@@ -2936,7 +2932,7 @@ long vwrite(char *buf, char *addr, unsigned long count)
 		if (!count)
 			break;
 
-		if (!(va->flags & VM_VM_AREA))
+		if (!va->vm)
 			continue;
 
 		vm = va->vm;
@@ -3466,10 +3462,10 @@ static int s_show(struct seq_file *m, void *p)
 	va = list_entry(p, struct vmap_area, list);
 
 	/*
-	 * 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.
+	 * s_show can encounter race with remove_vm_area, !vm on behalf
+	 * of vmap area is being tear down or vm_map_ram allocation.
 	 */
-	if (!(va->flags & VM_VM_AREA)) {
+	if (!va->vm) {
 		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);
-- 
2.21.0

Re: [PATCH v6 2/2] mm/vmalloc: modify struct vmap_area to reduce its size

[Uladzislau Rezki]

On Tue, Jul 16, 2019 at 11:26:56PM +0800, Pengfei Li wrote:
> Objective
> ---------
> The current implementation of struct vmap_area wasted space.
> 
> After applying this commit, sizeof(struct vmap_area) has been
> reduced from 11 words to 8 words.
> 
> Description
> -----------
> 1) Pack "subtree_max_size", "vm" and "purge_list".
> This is no problem because
>     A) "subtree_max_size" is only used when vmap_area is in
>        "free" tree
>     B) "vm" is only used when vmap_area is in "busy" tree
>     C) "purge_list" is only used when vmap_area is in
>        vmap_purge_list
> 
> 2) Eliminate "flags".
> Since only one flag VM_VM_AREA is being used, and the same
> thing can be done by judging whether "vm" is NULL, then the
> "flags" can be eliminated.
> 
> Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
> Suggested-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
>  include/linux/vmalloc.h | 20 +++++++++++++-------
>  mm/vmalloc.c            | 24 ++++++++++--------------
>  2 files changed, 23 insertions(+), 21 deletions(-)
> 
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 9b21d0047710..a1334bd18ef1 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -51,15 +51,21 @@ struct vmap_area {
>  	unsigned long va_start;
>  	unsigned long va_end;
>  
> -	/*
> -	 * Largest available free size in subtree.
> -	 */
> -	unsigned long subtree_max_size;
> -	unsigned long flags;
>  	struct rb_node rb_node;         /* address sorted rbtree */
>  	struct list_head list;          /* address sorted list */
> -	struct llist_node purge_list;    /* "lazy purge" list */
> -	struct vm_struct *vm;
> +
> +	/*
> +	 * The following three variables can be packed, because
> +	 * a vmap_area object is always one of the three states:
> +	 *    1) in "free" tree (root is vmap_area_root)
> +	 *    2) in "busy" tree (root is free_vmap_area_root)
> +	 *    3) in purge list  (head is vmap_purge_list)
> +	 */
> +	union {
> +		unsigned long subtree_max_size; /* in "free" tree */
> +		struct vm_struct *vm;           /* in "busy" tree */
> +		struct llist_node purge_list;   /* in purge list */
> +	};
>  };
>  
>  /*
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 71d8040a8a0b..2f7edc0466e7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -329,7 +329,6 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
>  #define DEBUG_AUGMENT_PROPAGATE_CHECK 0
>  #define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
>  
> -#define VM_VM_AREA	0x04
>  
>  static DEFINE_SPINLOCK(vmap_area_lock);
>  /* Export for kexec only */
> @@ -1115,7 +1114,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
>  
>  	va->va_start = addr;
>  	va->va_end = addr + size;
> -	va->flags = 0;
> +	va->vm = NULL;
>  	insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
>  
>  	spin_unlock(&vmap_area_lock);
> @@ -1922,7 +1921,6 @@ void __init vmalloc_init(void)
>  		if (WARN_ON_ONCE(!va))
>  			continue;
>  
> -		va->flags = VM_VM_AREA;
>  		va->va_start = (unsigned long)tmp->addr;
>  		va->va_end = va->va_start + tmp->size;
>  		va->vm = tmp;
> @@ -2020,7 +2018,6 @@ static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
>  	vm->size = va->va_end - va->va_start;
>  	vm->caller = caller;
>  	va->vm = vm;
> -	va->flags |= VM_VM_AREA;
>  	spin_unlock(&vmap_area_lock);
>  }
>  
> @@ -2125,10 +2122,10 @@ struct vm_struct *find_vm_area(const void *addr)
>  	struct vmap_area *va;
>  
>  	va = find_vmap_area((unsigned long)addr);
> -	if (va && va->flags & VM_VM_AREA)
> -		return va->vm;
> +	if (!va)
> +		return NULL;
>  
> -	return NULL;
> +	return va->vm;
>  }
>  
>  /**
> @@ -2149,11 +2146,10 @@ struct vm_struct *remove_vm_area(const void *addr)
>  
>  	spin_lock(&vmap_area_lock);
>  	va = __find_vmap_area((unsigned long)addr);
> -	if (va && va->flags & VM_VM_AREA) {
> +	if (va && va->vm) {
>  		struct vm_struct *vm = va->vm;
>  
>  		va->vm = NULL;
> -		va->flags &= ~VM_VM_AREA;
>  		spin_unlock(&vmap_area_lock);
>  
>  		kasan_free_shadow(vm);
> @@ -2856,7 +2852,7 @@ long vread(char *buf, char *addr, unsigned long count)
>  		if (!count)
>  			break;
>  
> -		if (!(va->flags & VM_VM_AREA))
> +		if (!va->vm)
>  			continue;
>  
>  		vm = va->vm;
> @@ -2936,7 +2932,7 @@ long vwrite(char *buf, char *addr, unsigned long count)
>  		if (!count)
>  			break;
>  
> -		if (!(va->flags & VM_VM_AREA))
> +		if (!va->vm)
>  			continue;
>  
>  		vm = va->vm;
> @@ -3466,10 +3462,10 @@ static int s_show(struct seq_file *m, void *p)
>  	va = list_entry(p, struct vmap_area, list);
>  
>  	/*
> -	 * 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.
> +	 * s_show can encounter race with remove_vm_area, !vm on behalf
> +	 * of vmap area is being tear down or vm_map_ram allocation.
>  	 */
> -	if (!(va->flags & VM_VM_AREA)) {
> +	if (!va->vm) {
>  		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);
> -- 
> 2.21.0
> 

This patch depends on https://lkml.org/lkml/2019/7/16/276 and looks ok
to me, so

Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

Thanks!

--
Vlad Rezki

Re: [PATCH v6 1/2] mm/vmalloc: do not keep unpurged areas in the busy tree

[Andrew Morton]

On Tue, 16 Jul 2019 23:26:55 +0800 Pengfei Li <lpf.vector@gmail.com> wrote:

> From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
> 
> The busy tree can be quite big, even though the area is freed
> or unmapped it still stays there until "purge" logic removes
> it.
> 
> 1) Optimize and reduce the size of "busy" tree by removing a
> node from it right away as soon as user triggers free paths.
> It is possible to do so, because the allocation is done using
> another augmented tree.
> 
> The vmalloc test driver shows the difference, for example the
> "fix_size_alloc_test" is ~11% better comparing with default
> configuration:
> 
> sudo ./test_vmalloc.sh performance
> 
> <default>
> Summary: fix_size_alloc_test loops: 1000000 avg: 993985 usec
> Summary: full_fit_alloc_test loops: 1000000 avg: 973554 usec
> Summary: long_busy_list_alloc_test loops: 1000000 avg: 12617652 usec
> <default>
> 
> <this patch>
> Summary: fix_size_alloc_test loops: 1000000 avg: 882263 usec
> Summary: full_fit_alloc_test loops: 1000000 avg: 973407 usec
> Summary: long_busy_list_alloc_test loops: 1000000 avg: 12593929 usec
> <this patch>
> 
> 2) Since the busy tree now contains allocated areas only and does
> not interfere with lazily free nodes, introduce the new function
> show_purge_info() that dumps "unpurged" areas that is propagated
> through "/proc/vmallocinfo".
> 
> 3) Eliminate VM_LAZY_FREE flag.
> 
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

This should have included your signed-off-by, since you were on the
patch delivery path.  (Documentation/process/submitting-patches.rst,
section 11).

Please send along your signed-off-by?

Re: [PATCH v6 1/2] mm/vmalloc: do not keep unpurged areas in the busy tree

[Pengfei Li]

Thanks.

Signed-off-by: Pengfei Li <lpf.vector@gmail.com>

On Thu, Jul 25, 2019 at 10:36 AM Andrew Morton
<akpm@linux-foundation.org> wrote:
>
> On Tue, 16 Jul 2019 23:26:55 +0800 Pengfei Li <lpf.vector@gmail.com> wrote:
>
> > From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
> >
> > The busy tree can be quite big, even though the area is freed
> > or unmapped it still stays there until "purge" logic removes
> > it.
> >
> > 1) Optimize and reduce the size of "busy" tree by removing a
> > node from it right away as soon as user triggers free paths.
> > It is possible to do so, because the allocation is done using
> > another augmented tree.
> >
> > The vmalloc test driver shows the difference, for example the
> > "fix_size_alloc_test" is ~11% better comparing with default
> > configuration:
> >
> > sudo ./test_vmalloc.sh performance
> >
> > <default>
> > Summary: fix_size_alloc_test loops: 1000000 avg: 993985 usec
> > Summary: full_fit_alloc_test loops: 1000000 avg: 973554 usec
> > Summary: long_busy_list_alloc_test loops: 1000000 avg: 12617652 usec
> > <default>
> >
> > <this patch>
> > Summary: fix_size_alloc_test loops: 1000000 avg: 882263 usec
> > Summary: full_fit_alloc_test loops: 1000000 avg: 973407 usec
> > Summary: long_busy_list_alloc_test loops: 1000000 avg: 12593929 usec
> > <this patch>
> >
> > 2) Since the busy tree now contains allocated areas only and does
> > not interfere with lazily free nodes, introduce the new function
> > show_purge_info() that dumps "unpurged" areas that is propagated
> > through "/proc/vmallocinfo".
> >
> > 3) Eliminate VM_LAZY_FREE flag.
> >
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
>
> This should have included your signed-off-by, since you were on the
> patch delivery path.  (Documentation/process/submitting-patches.rst,
> section 11).
>
> Please send along your signed-off-by?