[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH 07/15] qapi: use mmap for QmpInputVisitor

From: Peter Lieven
Subject: Re: [Qemu-devel] [PATCH 07/15] qapi: use mmap for QmpInputVisitor
Date: Tue, 28 Jun 2016 11:39:03 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0

Am 28.06.2016 um 11:29 schrieb Dr. David Alan Gilbert:
* Peter Lieven (address@hidden) wrote:
this struct is approx 75kB
I wonder why it's so large.

The stack size in QmpInputVisitor; it's got a 1024 element stack
(QIV_STACK_SIZE) and I bet we never use anywhere near that.

But even then that's 1024 * a 3 pointer stack object, 24 bytes -
I don't see where the rest of that 75kB comes from.

Sorry, I had a wrong size in mind. Its 24736 bytes. But thats
still larger than expecetd, right?

I'm a little wary about turning all these malloc's into mmap's
because we do seem to use things like input visitors for small
things; don't the cost of doing the mmap's add up in time
instead of space?

Sure, we should discuss this. The series should act as a base for

None of the things I changed into mmap are continously called
during VM runtime. So it most likely only happens at setup of the

It seems that the worst impact hat the PhysPageMap in exec.c


reply via email to

[Prev in Thread] Current Thread [Next in Thread]