Messages in this thread | | | Date | Wed, 23 Jul 2014 13:54:07 +0100 | From | Alasdair G Kergon <> | Subject | Re: [dm-devel] [PATCH] md/dm-ioctl.c: optimize memory allocation in copy_params |
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On Wed, Jul 23, 2014 at 08:16:58AM -0400, Mikulas Patocka wrote: > So, it means that you do not use device mapper at all. So, why are you > trying to change memory allocation in device mapper?
So the *test* they run is asking device-mapper to briefly reserve a 64KB buffer when there is no data to report: The answer is not to run that pointless test:)
And if a single 64KB allocation really is a big deal, then patch 'vold' in userspace so it doesn't ask for 64KB when it clearly doesn't need it!
+ int Devmapper::dumpState(SocketClient *c) { + char *buffer = (char *) malloc(1024 * 64);
The code has just #define DEVMAPPER_BUFFER_SIZE 4096 for all the other dm ioctls it issues.
Only use a larger value when it is needed i.e. if DM_BUFFER_FULL_FLAG gets set.
Alasdair
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