#include <linux/audit.h>
#include <linux/khugepaged.h>
#include <linux/uprobes.h>
+#include <linux/rbtree_augmented.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
*/
struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
+/*
+ * The global memory commitment made in the system can be a metric
+ * that can be used to drive ballooning decisions when Linux is hosted
+ * as a guest. On Hyper-V, the host implements a policy engine for dynamically
+ * balancing memory across competing virtual machines that are hosted.
+ * Several metrics drive this policy engine including the guest reported
+ * memory commitment.
+ */
+unsigned long vm_memory_committed(void)
+{
+ return percpu_counter_read_positive(&vm_committed_as);
+}
+EXPORT_SYMBOL_GPL(vm_memory_committed);
+
/*
* Check that a process has enough memory to allocate a new virtual
* mapping. 0 means there is enough memory for the allocation to
return retval;
}
+static long vma_compute_subtree_gap(struct vm_area_struct *vma)
+{
+ unsigned long max, subtree_gap;
+ max = vma->vm_start;
+ if (vma->vm_prev)
+ max -= vma->vm_prev->vm_end;
+ if (vma->vm_rb.rb_left) {
+ subtree_gap = rb_entry(vma->vm_rb.rb_left,
+ struct vm_area_struct, vm_rb)->rb_subtree_gap;
+ if (subtree_gap > max)
+ max = subtree_gap;
+ }
+ if (vma->vm_rb.rb_right) {
+ subtree_gap = rb_entry(vma->vm_rb.rb_right,
+ struct vm_area_struct, vm_rb)->rb_subtree_gap;
+ if (subtree_gap > max)
+ max = subtree_gap;
+ }
+ return max;
+}
+
#ifdef CONFIG_DEBUG_VM_RB
static int browse_rb(struct rb_root *root)
{
- int i = 0, j;
+ int i = 0, j, bug = 0;
struct rb_node *nd, *pn = NULL;
unsigned long prev = 0, pend = 0;
for (nd = rb_first(root); nd; nd = rb_next(nd)) {
struct vm_area_struct *vma;
vma = rb_entry(nd, struct vm_area_struct, vm_rb);
- if (vma->vm_start < prev)
- printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
- if (vma->vm_start < pend)
+ if (vma->vm_start < prev) {
+ printk("vm_start %lx prev %lx\n", vma->vm_start, prev);
+ bug = 1;
+ }
+ if (vma->vm_start < pend) {
printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
- if (vma->vm_start > vma->vm_end)
- printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
+ bug = 1;
+ }
+ if (vma->vm_start > vma->vm_end) {
+ printk("vm_end %lx < vm_start %lx\n",
+ vma->vm_end, vma->vm_start);
+ bug = 1;
+ }
+ if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
+ printk("free gap %lx, correct %lx\n",
+ vma->rb_subtree_gap,
+ vma_compute_subtree_gap(vma));
+ bug = 1;
+ }
i++;
pn = nd;
prev = vma->vm_start;
pend = vma->vm_end;
}
j = 0;
- for (nd = pn; nd; nd = rb_prev(nd)) {
+ for (nd = pn; nd; nd = rb_prev(nd))
j++;
+ if (i != j) {
+ printk("backwards %d, forwards %d\n", j, i);
+ bug = 1;
+ }
+ return bug ? -1 : i;
+}
+
+static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
+{
+ struct rb_node *nd;
+
+ for (nd = rb_first(root); nd; nd = rb_next(nd)) {
+ struct vm_area_struct *vma;
+ vma = rb_entry(nd, struct vm_area_struct, vm_rb);
+ BUG_ON(vma != ignore &&
+ vma->rb_subtree_gap != vma_compute_subtree_gap(vma));
}
- if (i != j)
- printk("backwards %d, forwards %d\n", j, i), i = 0;
- return i;
}
void validate_mm(struct mm_struct *mm)
{
int bug = 0;
int i = 0;
+ unsigned long highest_address = 0;
struct vm_area_struct *vma = mm->mmap;
while (vma) {
struct anon_vma_chain *avc;
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_verify(avc);
vma_unlock_anon_vma(vma);
+ highest_address = vma->vm_end;
vma = vma->vm_next;
i++;
}
- if (i != mm->map_count)
- printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
+ if (i != mm->map_count) {
+ printk("map_count %d vm_next %d\n", mm->map_count, i);
+ bug = 1;
+ }
+ if (highest_address != mm->highest_vm_end) {
+ printk("mm->highest_vm_end %lx, found %lx\n",
+ mm->highest_vm_end, highest_address);
+ bug = 1;
+ }
i = browse_rb(&mm->mm_rb);
- if (i != mm->map_count)
- printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
+ if (i != mm->map_count) {
+ printk("map_count %d rb %d\n", mm->map_count, i);
+ bug = 1;
+ }
BUG_ON(bug);
}
#else
+#define validate_mm_rb(root, ignore) do { } while (0)
#define validate_mm(mm) do { } while (0)
#endif
+RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb,
+ unsigned long, rb_subtree_gap, vma_compute_subtree_gap)
+
+/*
+ * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
+ * vma->vm_prev->vm_end values changed, without modifying the vma's position
+ * in the rbtree.
+ */
+static void vma_gap_update(struct vm_area_struct *vma)
+{
+ /*
+ * As it turns out, RB_DECLARE_CALLBACKS() already created a callback
+ * function that does exacltly what we want.
+ */
+ vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
+}
+
+static inline void vma_rb_insert(struct vm_area_struct *vma,
+ struct rb_root *root)
+{
+ /* All rb_subtree_gap values must be consistent prior to insertion */
+ validate_mm_rb(root, NULL);
+
+ rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
+}
+
+static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
+{
+ /*
+ * All rb_subtree_gap values must be consistent prior to erase,
+ * with the possible exception of the vma being erased.
+ */
+ validate_mm_rb(root, vma);
+
+ /*
+ * Note rb_erase_augmented is a fairly large inline function,
+ * so make sure we instantiate it only once with our desired
+ * augmented rbtree callbacks.
+ */
+ rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
+}
+
/*
* vma has some anon_vma assigned, and is already inserted on that
* anon_vma's interval trees.
void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
struct rb_node **rb_link, struct rb_node *rb_parent)
{
+ /* Update tracking information for the gap following the new vma. */
+ if (vma->vm_next)
+ vma_gap_update(vma->vm_next);
+ else
+ mm->highest_vm_end = vma->vm_end;
+
+ /*
+ * vma->vm_prev wasn't known when we followed the rbtree to find the
+ * correct insertion point for that vma. As a result, we could not
+ * update the vma vm_rb parents rb_subtree_gap values on the way down.
+ * So, we first insert the vma with a zero rb_subtree_gap value
+ * (to be consistent with what we did on the way down), and then
+ * immediately update the gap to the correct value. Finally we
+ * rebalance the rbtree after all augmented values have been set.
+ */
rb_link_node(&vma->vm_rb, rb_parent, rb_link);
- rb_insert_color(&vma->vm_rb, &mm->mm_rb);
+ vma->rb_subtree_gap = 0;
+ vma_gap_update(vma);
+ vma_rb_insert(vma, &mm->mm_rb);
}
static void __vma_link_file(struct vm_area_struct *vma)
__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev)
{
- struct vm_area_struct *next = vma->vm_next;
+ struct vm_area_struct *next;
- prev->vm_next = next;
+ vma_rb_erase(vma, &mm->mm_rb);
+ prev->vm_next = next = vma->vm_next;
if (next)
next->vm_prev = prev;
- rb_erase(&vma->vm_rb, &mm->mm_rb);
if (mm->mmap_cache == vma)
mm->mmap_cache = prev;
}
struct rb_root *root = NULL;
struct anon_vma *anon_vma = NULL;
struct file *file = vma->vm_file;
+ bool start_changed = false, end_changed = false;
long adjust_next = 0;
int remove_next = 0;
vma_interval_tree_remove(next, root);
}
- vma->vm_start = start;
- vma->vm_end = end;
+ if (start != vma->vm_start) {
+ vma->vm_start = start;
+ start_changed = true;
+ }
+ if (end != vma->vm_end) {
+ vma->vm_end = end;
+ end_changed = true;
+ }
vma->vm_pgoff = pgoff;
if (adjust_next) {
next->vm_start += adjust_next << PAGE_SHIFT;
* (it may either follow vma or precede it).
*/
__insert_vm_struct(mm, insert);
+ } else {
+ if (start_changed)
+ vma_gap_update(vma);
+ if (end_changed) {
+ if (!next)
+ mm->highest_vm_end = end;
+ else if (!adjust_next)
+ vma_gap_update(next);
+ }
}
if (anon_vma) {
* we must remove another next too. It would clutter
* up the code too much to do both in one go.
*/
- if (remove_next == 2) {
- next = vma->vm_next;
+ next = vma->vm_next;
+ if (remove_next == 2)
goto again;
- }
+ else if (next)
+ vma_gap_update(next);
+ else
+ mm->highest_vm_end = end;
}
if (insert && file)
uprobe_mmap(insert);
* memory so no accounting is necessary
*/
file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len,
- VM_NORESERVE, &user,
- HUGETLB_ANONHUGE_INODE);
+ VM_NORESERVE,
+ &user, HUGETLB_ANONHUGE_INODE,
+ (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
if (IS_ERR(file))
return PTR_ERR(file);
}
*
* Answer: Yes, several device drivers can do it in their
* f_op->mmap method. -DaveM
+ * Bug: If addr is changed, prev, rb_link, rb_parent should
+ * be updated for vma_link()
*/
+ WARN_ON_ONCE(addr != vma->vm_start);
+
addr = vma->vm_start;
pgoff = vma->vm_pgoff;
vm_flags = vma->vm_flags;
return error;
}
+unsigned long unmapped_area(struct vm_unmapped_area_info *info)
+{
+ /*
+ * We implement the search by looking for an rbtree node that
+ * immediately follows a suitable gap. That is,
+ * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
+ * - gap_end = vma->vm_start >= info->low_limit + length;
+ * - gap_end - gap_start >= length
+ */
+
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long length, low_limit, high_limit, gap_start, gap_end;
+
+ /* Adjust search length to account for worst case alignment overhead */
+ length = info->length + info->align_mask;
+ if (length < info->length)
+ return -ENOMEM;
+
+ /* Adjust search limits by the desired length */
+ if (info->high_limit < length)
+ return -ENOMEM;
+ high_limit = info->high_limit - length;
+
+ if (info->low_limit > high_limit)
+ return -ENOMEM;
+ low_limit = info->low_limit + length;
+
+ /* Check if rbtree root looks promising */
+ if (RB_EMPTY_ROOT(&mm->mm_rb))
+ goto check_highest;
+ vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
+ if (vma->rb_subtree_gap < length)
+ goto check_highest;
+
+ while (true) {
+ /* Visit left subtree if it looks promising */
+ gap_end = vma->vm_start;
+ if (gap_end >= low_limit && vma->vm_rb.rb_left) {
+ struct vm_area_struct *left =
+ rb_entry(vma->vm_rb.rb_left,
+ struct vm_area_struct, vm_rb);
+ if (left->rb_subtree_gap >= length) {
+ vma = left;
+ continue;
+ }
+ }
+
+ gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
+check_current:
+ /* Check if current node has a suitable gap */
+ if (gap_start > high_limit)
+ return -ENOMEM;
+ if (gap_end >= low_limit && gap_end - gap_start >= length)
+ goto found;
+
+ /* Visit right subtree if it looks promising */
+ if (vma->vm_rb.rb_right) {
+ struct vm_area_struct *right =
+ rb_entry(vma->vm_rb.rb_right,
+ struct vm_area_struct, vm_rb);
+ if (right->rb_subtree_gap >= length) {
+ vma = right;
+ continue;
+ }
+ }
+
+ /* Go back up the rbtree to find next candidate node */
+ while (true) {
+ struct rb_node *prev = &vma->vm_rb;
+ if (!rb_parent(prev))
+ goto check_highest;
+ vma = rb_entry(rb_parent(prev),
+ struct vm_area_struct, vm_rb);
+ if (prev == vma->vm_rb.rb_left) {
+ gap_start = vma->vm_prev->vm_end;
+ gap_end = vma->vm_start;
+ goto check_current;
+ }
+ }
+ }
+
+check_highest:
+ /* Check highest gap, which does not precede any rbtree node */
+ gap_start = mm->highest_vm_end;
+ gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
+ if (gap_start > high_limit)
+ return -ENOMEM;
+
+found:
+ /* We found a suitable gap. Clip it with the original low_limit. */
+ if (gap_start < info->low_limit)
+ gap_start = info->low_limit;
+
+ /* Adjust gap address to the desired alignment */
+ gap_start += (info->align_offset - gap_start) & info->align_mask;
+
+ VM_BUG_ON(gap_start + info->length > info->high_limit);
+ VM_BUG_ON(gap_start + info->length > gap_end);
+ return gap_start;
+}
+
+unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long length, low_limit, high_limit, gap_start, gap_end;
+
+ /* Adjust search length to account for worst case alignment overhead */
+ length = info->length + info->align_mask;
+ if (length < info->length)
+ return -ENOMEM;
+
+ /*
+ * Adjust search limits by the desired length.
+ * See implementation comment at top of unmapped_area().
+ */
+ gap_end = info->high_limit;
+ if (gap_end < length)
+ return -ENOMEM;
+ high_limit = gap_end - length;
+
+ if (info->low_limit > high_limit)
+ return -ENOMEM;
+ low_limit = info->low_limit + length;
+
+ /* Check highest gap, which does not precede any rbtree node */
+ gap_start = mm->highest_vm_end;
+ if (gap_start <= high_limit)
+ goto found_highest;
+
+ /* Check if rbtree root looks promising */
+ if (RB_EMPTY_ROOT(&mm->mm_rb))
+ return -ENOMEM;
+ vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
+ if (vma->rb_subtree_gap < length)
+ return -ENOMEM;
+
+ while (true) {
+ /* Visit right subtree if it looks promising */
+ gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
+ if (gap_start <= high_limit && vma->vm_rb.rb_right) {
+ struct vm_area_struct *right =
+ rb_entry(vma->vm_rb.rb_right,
+ struct vm_area_struct, vm_rb);
+ if (right->rb_subtree_gap >= length) {
+ vma = right;
+ continue;
+ }
+ }
+
+check_current:
+ /* Check if current node has a suitable gap */
+ gap_end = vma->vm_start;
+ if (gap_end < low_limit)
+ return -ENOMEM;
+ if (gap_start <= high_limit && gap_end - gap_start >= length)
+ goto found;
+
+ /* Visit left subtree if it looks promising */
+ if (vma->vm_rb.rb_left) {
+ struct vm_area_struct *left =
+ rb_entry(vma->vm_rb.rb_left,
+ struct vm_area_struct, vm_rb);
+ if (left->rb_subtree_gap >= length) {
+ vma = left;
+ continue;
+ }
+ }
+
+ /* Go back up the rbtree to find next candidate node */
+ while (true) {
+ struct rb_node *prev = &vma->vm_rb;
+ if (!rb_parent(prev))
+ return -ENOMEM;
+ vma = rb_entry(rb_parent(prev),
+ struct vm_area_struct, vm_rb);
+ if (prev == vma->vm_rb.rb_right) {
+ gap_start = vma->vm_prev ?
+ vma->vm_prev->vm_end : 0;
+ goto check_current;
+ }
+ }
+ }
+
+found:
+ /* We found a suitable gap. Clip it with the original high_limit. */
+ if (gap_end > info->high_limit)
+ gap_end = info->high_limit;
+
+found_highest:
+ /* Compute highest gap address at the desired alignment */
+ gap_end -= info->length;
+ gap_end -= (gap_end - info->align_offset) & info->align_mask;
+
+ VM_BUG_ON(gap_end < info->low_limit);
+ VM_BUG_ON(gap_end < gap_start);
+ return gap_end;
+}
+
/* Get an address range which is currently unmapped.
* For shmat() with addr=0.
*
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- unsigned long start_addr;
+ struct vm_unmapped_area_info info;
if (len > TASK_SIZE)
return -ENOMEM;
(!vma || addr + len <= vma->vm_start))
return addr;
}
- if (len > mm->cached_hole_size) {
- start_addr = addr = mm->free_area_cache;
- } else {
- start_addr = addr = TASK_UNMAPPED_BASE;
- mm->cached_hole_size = 0;
- }
-full_search:
- for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
- /* At this point: (!vma || addr < vma->vm_end). */
- if (TASK_SIZE - len < addr) {
- /*
- * Start a new search - just in case we missed
- * some holes.
- */
- if (start_addr != TASK_UNMAPPED_BASE) {
- addr = TASK_UNMAPPED_BASE;
- start_addr = addr;
- mm->cached_hole_size = 0;
- goto full_search;
- }
- return -ENOMEM;
- }
- if (!vma || addr + len <= vma->vm_start) {
- /*
- * Remember the place where we stopped the search:
- */
- mm->free_area_cache = addr + len;
- return addr;
- }
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
- addr = vma->vm_end;
- }
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = TASK_UNMAPPED_BASE;
+ info.high_limit = TASK_SIZE;
+ info.align_mask = 0;
+ return vm_unmapped_area(&info);
}
#endif
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
- unsigned long addr = addr0, start_addr;
+ unsigned long addr = addr0;
+ struct vm_unmapped_area_info info;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
return addr;
}
- /* check if free_area_cache is useful for us */
- if (len <= mm->cached_hole_size) {
- mm->cached_hole_size = 0;
- mm->free_area_cache = mm->mmap_base;
- }
-
-try_again:
- /* either no address requested or can't fit in requested address hole */
- start_addr = addr = mm->free_area_cache;
-
- if (addr < len)
- goto fail;
-
- addr -= len;
- do {
- /*
- * Lookup failure means no vma is above this address,
- * else if new region fits below vma->vm_start,
- * return with success:
- */
- vma = find_vma(mm, addr);
- if (!vma || addr+len <= vma->vm_start)
- /* remember the address as a hint for next time */
- return (mm->free_area_cache = addr);
-
- /* remember the largest hole we saw so far */
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
-
- /* try just below the current vma->vm_start */
- addr = vma->vm_start-len;
- } while (len < vma->vm_start);
-
-fail:
- /*
- * if hint left us with no space for the requested
- * mapping then try again:
- *
- * Note: this is different with the case of bottomup
- * which does the fully line-search, but we use find_vma
- * here that causes some holes skipped.
- */
- if (start_addr != mm->mmap_base) {
- mm->free_area_cache = mm->mmap_base;
- mm->cached_hole_size = 0;
- goto try_again;
- }
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.low_limit = PAGE_SIZE;
+ info.high_limit = mm->mmap_base;
+ info.align_mask = 0;
+ addr = vm_unmapped_area(&info);
/*
* A failed mmap() very likely causes application failure,
* can happen with large stack limits and large mmap()
* allocations.
*/
- mm->cached_hole_size = ~0UL;
- mm->free_area_cache = TASK_UNMAPPED_BASE;
- addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
- /*
- * Restore the topdown base:
- */
- mm->free_area_cache = mm->mmap_base;
- mm->cached_hole_size = ~0UL;
+ if (addr & ~PAGE_MASK) {
+ VM_BUG_ON(addr != -ENOMEM);
+ info.flags = 0;
+ info.low_limit = TASK_UNMAPPED_BASE;
+ info.high_limit = TASK_SIZE;
+ addr = vm_unmapped_area(&info);
+ }
return addr;
}
if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
error = acct_stack_growth(vma, size, grow);
if (!error) {
+ /*
+ * vma_gap_update() doesn't support concurrent
+ * updates, but we only hold a shared mmap_sem
+ * lock here, so we need to protect against
+ * concurrent vma expansions.
+ * vma_lock_anon_vma() doesn't help here, as
+ * we don't guarantee that all growable vmas
+ * in a mm share the same root anon vma.
+ * So, we reuse mm->page_table_lock to guard
+ * against concurrent vma expansions.
+ */
+ spin_lock(&vma->vm_mm->page_table_lock);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_end = address;
anon_vma_interval_tree_post_update_vma(vma);
+ if (vma->vm_next)
+ vma_gap_update(vma->vm_next);
+ else
+ vma->vm_mm->highest_vm_end = address;
+ spin_unlock(&vma->vm_mm->page_table_lock);
+
perf_event_mmap(vma);
}
}
if (grow <= vma->vm_pgoff) {
error = acct_stack_growth(vma, size, grow);
if (!error) {
+ /*
+ * vma_gap_update() doesn't support concurrent
+ * updates, but we only hold a shared mmap_sem
+ * lock here, so we need to protect against
+ * concurrent vma expansions.
+ * vma_lock_anon_vma() doesn't help here, as
+ * we don't guarantee that all growable vmas
+ * in a mm share the same root anon vma.
+ * So, we reuse mm->page_table_lock to guard
+ * against concurrent vma expansions.
+ */
+ spin_lock(&vma->vm_mm->page_table_lock);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_start = address;
vma->vm_pgoff -= grow;
anon_vma_interval_tree_post_update_vma(vma);
+ vma_gap_update(vma);
+ spin_unlock(&vma->vm_mm->page_table_lock);
+
perf_event_mmap(vma);
}
}
insertion_point = (prev ? &prev->vm_next : &mm->mmap);
vma->vm_prev = NULL;
do {
- rb_erase(&vma->vm_rb, &mm->mm_rb);
+ vma_rb_erase(vma, &mm->mm_rb);
mm->map_count--;
tail_vma = vma;
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
*insertion_point = vma;
- if (vma)
+ if (vma) {
vma->vm_prev = prev;
+ vma_gap_update(vma);
+ } else
+ mm->highest_vm_end = prev ? prev->vm_end : 0;
tail_vma->vm_next = NULL;
if (mm->unmap_area == arch_unmap_area)
addr = prev ? prev->vm_end : mm->mmap_base;
projects / can-eth-gw-linux.git / blobdiff