Re: [PATCH v4 8/8] mm: support both pid and pidfd for process_madvise

On Wed, 2020-02-12 at 15:39 -0800, Minchan Kim wrote:

There is a demand[1] to support pid as well pidfd for process_madvise
to reduce unnecessary syscall to get pidfd if the user has control of
the target process(ie, they could guarantee the process is not gone
or pid is not reused. Or, it might be okay to give a hint to wrong
process).

This patch aims for supporting both options like waitid(2). So, the
syscall is currently,

	int process_madvise(int which, pid_t pid, void *addr,
		size_t length, int advise, unsigned long flag);

@which is actually idtype_t for userspace libray and currently,
it supports P_PID and P_PIDFD.

[1]  https://lore.kernel.org/linux-mm/9d849087-3359-c4ab-fbec-859e8186c509-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org/

Cc: Christian Brauner <redacted>
Suggested-by: Kirill Tkhai <redacted>
Signed-off-by: Minchan Kim <redacted>

So if you move patch 7 up before patch 2 you could squash this patch with
your current patch 2 and drop one patch from your series. It would
probably help to reduce the review overhead as well.