On Tue, Mar 07, 2017 at 06:24:37PM +0300, Kirill A. Shutemov wrote: > On Mon, Mar 06, 2017 at 11:15:08AM +0900, Minchan Kim wrote: > > Hi Anshuman, > > > > On Fri, Mar 03, 2017 at 06:06:38PM +0530, Anshuman Khandual wrote: > > > On 03/02/2017 12:09 PM, Minchan Kim wrote: > > > > ttu don't need to return SWAP_MLOCK. Instead, just return SWAP_FAIL > > > > because it means the page is not-swappable so it should move to > > > > another LRU list(active or unevictable). putback friends will > > > > move it to right list depending on the page's LRU flag. > > > > > > Right, if it cannot be swapped out there is not much difference with > > > SWAP_FAIL once we change the callers who expected to see a SWAP_MLOCK > > > return instead. > > > > > > > > > > > A side effect is shrink_page_list accounts unevictable list movement > > > > by PGACTIVATE but I don't think it corrupts something severe. > > > > > > Not sure I got that, could you please elaborate on this. We will still > > > activate the page and put it in an appropriate LRU list if it is marked > > > mlocked ? > > > > Right. putback_iactive_pages/putback_lru_page has a logic to filter > > out unevictable pages and move them to unevictable LRU list so it > > doesn't break LRU change behavior but the concern is until now, > > we have accounted PGACTIVATE for only evictable LRU list page but > > by this change, it accounts it to unevictable LRU list as well. > > However, although I don't think it's big problem in real practice, > > we can fix it simply with checking PG_mlocked if someone reports. > > I think it's better to do this pro-actively. Let's hide both pgactivate++ > and SetPageActive() under "if (!PageMlocked())". > SetPageActive() is not free. I will consider it in next spin. Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
