Patchwork [3/5] HACKING: add memory management rules

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Submitter Blue Swirl
Date Aug. 26, 2010, 6:38 p.m.
Message ID <AANLkTim5vR_Q-M4rAowfiak+7R46gJiAKMy-CaZDHya6@mail.gmail.com>
Download mbox | patch
Permalink /patch/62799/
State New
Headers show

Comments

Blue Swirl - Aug. 26, 2010, 6:38 p.m.
Add memory management rules, somewhat like libvirt HACKING.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
---
 HACKING |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

+emulators.
Kevin Wolf - Aug. 27, 2010, 8:45 a.m.
Am 26.08.2010 20:38, schrieb Blue Swirl:
> Add memory management rules, somewhat like libvirt HACKING.
> 
> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
> ---
>  HACKING |   11 +++++++++++
>  1 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/HACKING b/HACKING
> index 19fc874..554009e 100644
> --- a/HACKING
> +++ b/HACKING
> @@ -72,3 +72,14 @@ Typedefs are used to eliminate the redundant
> 'struct' keyword.
>  2.4. Reserved namespaces in C
>  Underscore capital, double underscore, and underscore 't' suffixes should be
>  avoided.
> +
> +3. Low level memory management
> +
> +Use of the malloc/free/realloc/calloc/valloc/memalign/posix_memalign
> +APIs is not allowed in the QEMU codebase. Instead of these routines,
> +use the replacement qemu_malloc/qemu_mallocz/qemu_realloc/qemu_free or
> +qemu_vmalloc/qemu_memalign/qemu_vfree APIs.
> +
> +Memory allocated by qemu_vmalloc or qemu_memalign must be freed with
> +qemu_vfree, since breaking this will cause problems on Win32 and user
> +emulators.

Maybe add that a NULL check for the qemu_malloc result is redundant.

And a warning about the stupid qemu_malloc(0) behaviour would be
appropriate, too. Because if you don't know it, you'll write buggy code.

Kevin

Patch

diff --git a/HACKING b/HACKING
index 19fc874..554009e 100644
--- a/HACKING
+++ b/HACKING
@@ -72,3 +72,14 @@  Typedefs are used to eliminate the redundant
'struct' keyword.
 2.4. Reserved namespaces in C
 Underscore capital, double underscore, and underscore 't' suffixes should be
 avoided.
+
+3. Low level memory management
+
+Use of the malloc/free/realloc/calloc/valloc/memalign/posix_memalign
+APIs is not allowed in the QEMU codebase. Instead of these routines,
+use the replacement qemu_malloc/qemu_mallocz/qemu_realloc/qemu_free or
+qemu_vmalloc/qemu_memalign/qemu_vfree APIs.
+
+Memory allocated by qemu_vmalloc or qemu_memalign must be freed with
+qemu_vfree, since breaking this will cause problems on Win32 and user