android: binder: use VM_ALLOC to get vm area
VM_IOREMAP is used to access hardware through a mechanism called
I/O mapped memory. Android binder is a IPC machanism which will
not access I/O memory.
And VM_IOREMAP has alignment requiement which may not needed in
binder.
__get_vm_area_node()
{
...
if (flags & VM_IOREMAP)
align = 1ul << clamp_t(int, fls_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
...
}
This patch will save some kernel vm area, especially for 32bit os.
In 32bit OS, kernel vm area is only 240MB. We may got below
error when launching a app:
<3>[ 4482.440053] binder_alloc: binder_alloc_mmap_handler: 15728 8ce67000-8cf65000 get_vm_area failed -12
<3>[ 4483.218817] binder_alloc: binder_alloc_mmap_handler: 15745 8ce67000-8cf65000 get_vm_area failed -12
Link: https://lkml.org/lkml/2018/1/9/1260
Change-Id: Id3a715da6060191d05384697a4f266f82cdcba2b
Patch-mainline: linux-kernel @ 01/10/18, 10:49
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 1c76daa..abb56a9 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -669,7 +669,7 @@
goto err_already_mapped;
}
- area = get_vm_area(vma->vm_end - vma->vm_start, VM_IOREMAP);
+ area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
if (area == NULL) {
ret = -ENOMEM;
failure_string = "get_vm_area";