On Thu, Mar 05, 2020 at 07:15:10PM +0100, Vlastimil Babka wrote: > On 3/2/20 8:36 PM, Minchan Kim wrote: > > There is usecase that System Management Software(SMS) want to give > > a memory hint like MADV_[COLD|PAGEEOUT] to other processes and > > in the case of Android, it is the ActivityManagerService. > > > > It's similar in spirit to madvise(MADV_WONTNEED), but the information > > You mean MADV_DONTNEED? Mean to DONT_NEED's future version. > > > required to make the reclaim decision is not known to the app. > > This seems to be mixing up the differences between MADV_DONTNEED and > COLD/PAGEOUT and self-imposed vs external memory hints? Sorry, I don't understand what you want here. > > > Instead, > > it is known to the centralized userspace daemon(ActivityManagerService), > > and that daemon must be able to initiate reclaim on its own without > > any app involvement. > > > > To solve the issue, this patch introduces a new syscall process_madvise(2). > > It uses pidfd of an external process to give the hint. > > > > int process_madvise(int pidfd, void *addr, size_t length, int advise, > > unsigned long flag); > > It's more common to call the argument 'flags' not 'flag'? The code seems to call > it flags. Also in line with madvise(2), the 'advise' argument should rather be > 'advice'. This is more important for the manpage, but let's be consistent. Yub, I will send the patch along with your comment in previous patch. > > ... > > > > > Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> > > For the core parts, > Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> Thanks for the review!
