Re: [PATCH] mm/cma: Add sysfs file 'release_pages_success'

[Andrew Morton]

On Wed, 7 Feb 2024 10:04:31 +0530 Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote:

> > The changelog doesn't explain why Linux needs this feature.  The value
> > to our users.  Perhaps that info is buried in the link which is buried
> > below the ^---$, but as this is the most important part of a changelog,
> > it really should be spelled out here, completely and carefully please.
> 
> Does this look better ?
> 
> mm/cma: Add sysfs file 'release_pages_success'
> 
> This adds the following new sysfs file tracking the number of successfully
> released pages from a given CMA heap area. This file will be available via
> CONFIG_CMA_SYSFS and help in determining active CMA pages available on the
> CMA heap area. This adds a new 'nr_pages_released' (CONFIG_CMA_SYSFS) into
> 'struct cma' which gets updated during cma_release().
> 
> /sys/kernel/mm/cma/<cma-heap-area>/release_pages_success
> 
> After this change, an user will be able to find active CMA pages available
> in a given CMA heap area via the following method.
> 
> Active pages = alloc_pages_success - release_pages_success
> 
> That's valuable information for both software designers, and system admins
> as it allows them to tune the number of CMA pages available in the system.
> This increases user visibility for allocated CMA area and its utilization.

yup, thanks.  I added the patch with the above for a changelog.