I have introduced the M_ZERO flag to the kernel malloc, which provides the service to bzero() the memory allocted.

In the kernel sources, the archetypical change to use this facility looks like this:

Old code: databuf = malloc(length, M_DEVBUF, M_WAITOK); bzero(databuf, length);

New code: databuf = malloc(length, M_DEVBUF, M_WAITOK | M_ZERO);

Short term the benefit is less clutter in the code and a smaller cache footprint of the kernel.

Long term, this will allow us to optimize malloc(9) by allocating from a pool of memory which is zero'ed whenever the cpu is idle.

If anybody is looking for a simple task to perform in the FreeBSD kernel: this is it.

A quick grep tells me that there are at least 91 files in the src/sys tree which could use this flag to simplify and optimize the code.

The ground rules for such a cleanup are:

Respect the style of the source file.

Don't make unrelated changes: If you spot other issues with the code as you read it, make a separate diff for those issues.

Bundle the patches at administrative boundaries: a directory at a time, a driver at a time etc etc.

Submit changes to the maintainer of the file (if any) or with send-pr.

Junior committers are encouraged to review and commit these PR's as they arrive

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