From: Ganesh Mahendran <opensource.ganesh@gmail.com>
To: gregkh@linuxfoundation.org, maco@android.com, tkjos@google.com,
arve@android.com
Cc: linux-kernel@vger.kernel.org,
Ganesh Mahendran <opensource.ganesh@gmail.com>
Subject: [PATCH v3] android: binder: use VM_ALLOC to get vm area
Date: Wed, 10 Jan 2018 10:49:05 +0800 [thread overview]
Message-ID: <1515552545-18311-1-git-send-email-opensource.ganesh@gmail.com> (raw)
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
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
----
V3: update comments
V2: update comments
---
drivers/android/binder_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 07b866a..5a426c8 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -670,7 +670,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
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";
--
1.9.1
next reply other threads:[~2018-01-10 2:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 2:49 Ganesh Mahendran [this message]
2018-01-22 15:54 ` [PATCH v3] android: binder: use VM_ALLOC to get vm area Greg KH
2018-01-22 17:02 ` Todd Kjos
2018-01-22 18:55 ` Arve Hjønnevåg
2018-01-24 5:24 ` Ganesh Mahendran
2018-01-25 2:06 ` Ganesh Mahendran
2018-01-24 14:33 ` Martijn Coenen
2018-01-25 2:09 ` Ganesh Mahendran
2018-01-25 9:51 ` Greg KH
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