On 06/06/2016 11:59 PM, Chen Feng wrote:
The idea is good, define the heap ids in header file is inconvenient.
But if we query the heaps information from user-space.
It need to maintain this ids and name userspace one by one. The code may
be complicated in different module user-space.
In android, the gralloc and other lib will all use ion to alloc memory.
This will make it more difficult to maintain user-space code.
This was a concern I had had as well. Anything that involves dynamic
probing is going to involve more tracking. Do you think some library
code in libion would help?
Thanks,
Laura
But beyond this, The new alloc2 with not-handle flag is good.
And the pull out of ioctl interface is also a good cleanup.
On 2016/6/7 2:23, Laura Abbott wrote:
The ABI for Ion's ioctl interface are a pain to work with. The heap IDs
are a 32-bit non-discoverable namespace that form part of the ABI. There's
no way to determine what ABI version is in use which leads to problems
if the ABI changes or needs to be updated.
This series is a first approach to give a better ABI for Ion. This includes:
- Following the advice in botching-up-ioctls.txt
- Ioctl for ABI version
- Dynamic assignment of heap ids
- queryable heap ids
- Runtime mapping of heap ids, including fallbacks. This avoids the need to
encode the fallbacks as an ABI.
I'm most interested in feedback if this ABI is actually an improvement and
usable. The heap id map/query interface seems error prone but I didn't have
a cleaner solution. There aren't any kernel APIs for the new features as the
focus was on a userspace API but I anticipate that following easily once
the userspace API is established.
Thanks,
Laura
P.S. Not to turn this into a bike shedding session but if you have suggestions
for a name for this framework other than Ion I would be interested to hear
them. Too many other things are already named Ion.
Laura Abbott (6):
staging: android: ion: return error value for ion_device_add_heap
staging: android: ion: Switch to using an idr to manage heaps
staging: android: ion: Drop heap type masks
staging: android: ion: Pull out ion ioctls to a separate file
staging: android: ion: Add an ioctl for ABI checking
staging: android: ion: Introduce new ioctls for dynamic heaps
drivers/staging/android/ion/Makefile | 3 +-
drivers/staging/android/ion/ion-ioctl.c | 243 ++++++++++++++++++
drivers/staging/android/ion/ion.c | 438 ++++++++++++++++----------------
drivers/staging/android/ion/ion_priv.h | 109 +++++++-
drivers/staging/android/uapi/ion.h | 164 +++++++++++-
5 files changed, 728 insertions(+), 229 deletions(-)
create mode 100644 drivers/staging/android/ion/ion-ioctl.c
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