On Mon, Mar 02, 2020 at 01:16:18PM -0800, Andrew Morton wrote:
> On Mon, 2 Mar 2020 11:36:23 -0800 Minchan Kim <minchan@xxxxxxxxxx> wrote:
>
> > Now, we have MADV_PAGEOUT and MADV_COLD as madvise hinting API. With that,
> > application could give hints to kernel what memory range are preferred to be
> > reclaimed. However, in some platform(e.g., Android), the information
> > required to make the hinting decision is not known to the app.
> > Instead, it is known to a centralized userspace daemon(e.g., ActivityManagerService),
> > and that daemon must be able to initiate reclaim on its own without any app
> > involvement.
> >
> > To solve the concern, this patch introduces new syscall - process_madvise(2).
> > Bascially, it's same with madvise(2) syscall but it has some differences.
> >
> > 1. It needs pidfd of target process to provide the hint
> > 2. It supports only MADV_{COLD|PAGEOUT|MERGEABLE|UNMEREABLE} at this moment.
> > Other hints in madvise will be opened when there are explicit requests from
> > community to prevent unexpected bugs we couldn't support.
> > 3. Only privileged processes can do something for other process's address
> > space.
> >
> > For more detail of the new API, please see "mm: introduce external memory hinting API"
> > description in this patchset.
>
> Thanks, I grabbed these.
>
> I massaged the patch titles significantly - mainly to alert readers to
> the fact that we're proposing a new syscall.
>
> Is a manpage for process_madvise(2) being prepared?
I will prepare it, Thanks!
