On Tue, Mar 5, 2024 at 10:00 PM Ryan Roberts <ryan.roberts@xxxxxxx> wrote: > > Hi Barry, > > On 18/02/2024 23:40, Barry Song wrote: > > On Tue, Feb 6, 2024 at 1:14 AM Ryan Roberts <ryan.roberts@xxxxxxx> wrote: > >> > >> On 05/02/2024 09:51, Barry Song wrote: > >>> +Chris, Suren and Chuanhua > >>> > >>> Hi Ryan, > [...] > >> > > > > Hi Ryan, > > I am running into some races especially while enabling large folio swap-out and > > swap-in both. some of them, i am still struggling with the detailed > > timing how they > > are happening. > > but the below change can help remove those bugs which cause corrupted data. > > I'm getting quite confused with all the emails flying around on this topic. Here > you were reporting a data corruption bug and your suggested fix below is the one > you have now posted at [1]. But in the thread at [1] we concluded that it is not > fixing a functional correctness issue, but is just an optimization in some > corner cases. So does the corruption issue still manifest? Did you manage to > root cause it? Is it a problem with my swap-out series or your swap-in series, > or pre-existing? Hi Ryan, It is not a problem of your swap-out series, but a problem of my swap-in series. The bug in swap-in series is triggered by the skipped PTEs in the thread[1], but my swap-in code should still be able to cope with this situation and survive it - a large folio might be partially but not completely unmapped after try_to_unmap_one(). I actually replied to you and explained all the details here[2], but guess you missed it :-) [1] https://lore.kernel.org/linux-mm/20240304103757.235352-1-21cnbao@xxxxxxxxx/ [2] https://lore.kernel.org/linux-mm/CAGsJ_4zdh5kOG7QP4UDaE-wmLFiTEJC2PX-_LxtOj=QrZSvkCA@xxxxxxxxxxxxxx/ apology this makes you confused. > > [1] https://lore.kernel.org/linux-mm/20240304103757.235352-1-21cnbao@xxxxxxxxx/ > > Thanks, > Ryan > Thanks Barry
