Re: [PATCH] mm: Free unused pages in kmalloc_order()

Re: [PATCH] mm: Free unused pages in kmalloc_order()

[Markus Elfring]

> kmalloc(1024, GFP_HIGHUSER) can allocate memory normally,
> kmalloc(64*1024, GFP_HIGHUSER) will cause a memory leak,

Would you like to explain the influence of the selected allocation size
in a different way?


> because alloc_pages returns highmem physical pages, but it cannot be directly
> converted into a virtual address and return NULL, the pages has not
> been released. Usually driver developers will not use the
> GFP_HIGHUSER flag to allocate memory in kmalloc, but I think this
> memory leak is not perfect, it is best to be fixed.

I suggest to improve this change description.

* Did you apply any special analysis tools?

* How do you think about to split the text into more sentences?

* Would you like to extend any software documentation?


> This is the first time I have posted a patch,

I find this information irrelevant for the proposed commit message.


> there may be something wrong.

There are usual risks to consider also for such software development.

Will it become helpful to add the tag “Fixes”?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=719fdd32921fb7e3208db8832d32ae1c2d68900f#n183

Regards,
Markus

Re: [PATCH] mm: Free unused pages in kmalloc_order()

[Matthew Wilcox]

On Sun, Jun 28, 2020 at 01:17:59PM +0200, Markus Elfring wrote:
> > kmalloc(1024, GFP_HIGHUSER) can allocate memory normally,
> > kmalloc(64*1024, GFP_HIGHUSER) will cause a memory leak,
> 
> Would you like to explain the influence of the selected allocation size
> in a different way?

Markus, this is not useful.  Please stop.