Re: [Qemu-devel] [PATCH v3] rcu: reduce more than 7MB heap memory by malloc_trim()

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Fri, Nov 24, 2017 at 02:30:30PM +0800, Yang Zhong wrote:
> diff --git a/configure b/configure
> index 0c6e757..6292ab0 100755
> --- a/configure
> +++ b/configure
> @@ -426,6 +426,7 @@ vxhs=""
>  supported_cpu="no"
>  supported_os="no"
>  bogus_os="no"
> +malloc_trim="yes"

Looks pretty good, sorry I forgot to mention two things:

Please add the --enable-malloc-trim/--disable-malloc-trim options so
it's easy to build QEMU with or without this feature.  For example, if
someone is debugging a performance issue they may wish to rebuild with
--disable-malloc-trim to confirm that trimming hasn't caused a
regression.

Also please change this line to malloc_trim="" so the "Disabling
malloc_trim with non-libc memory allocator" error message is only
printed when --enable-malloc-trim was explicitly given by the user.
Otherwise the message is always printed when QEMU is built with
jemalloc/tcmalloc - that's too noisy.

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