On Tue, Sep 3, 2024 at 2:36 PM Barry Song <21cnbao@xxxxxxxxx> wrote: > > On Wed, Sep 4, 2024 at 8:08 AM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > On Tue, 3 Sep 2024 11:38:37 -0700 Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > > > > > [ 39.157954] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007 > > > > [ 39.158288] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 > > > > [ 39.158634] R13: 0000000000002b9a R14: 0000000000000000 R15: 00007ffd619d5518 > > > > [ 39.158998] </TASK> > > > > [ 39.159226] ---[ end trace 0000000000000000 ]--- > > > > > > > > After reverting this or Usama's "mm: store zero pages to be swapped > > > > out in a bitmap", the problem is gone. I think these two patches may > > > > have some conflict that needs to be resolved. > > > > > > Yup. I saw this conflict coming and specifically asked for this > > > warning to be added in Usama's patch to catch it [1]. It served its > > > purpose. > > > > > > Usama's patch does not handle large folio swapin, because at the time > > > it was written we didn't have it. We expected Usama's series to land > > > sooner than this one, so the warning was to make sure that this series > > > handles large folio swapin in the zeromap code. Now that they are both > > > in mm-unstable, we are gonna have to figure this out. > > > > > > I suspect Usama's patches are closer to land so it's better to handle > > > this in this series, but I will leave it up to Usama and > > > Chuanhua/Barry to figure this out :) > > I believe handling this in swap-in might violate layer separation. > `swap_read_folio()` should be a reliable API to call, regardless of > whether `zeromap` is present. Therefore, the fix should likely be > within `zeromap` but not this `swap-in`. I’ll take a look at this with > Usama :-) I meant handling it within this series to avoid blocking Usama patches, not within this code. Thanks for taking a look, I am sure you and Usama will figure out the best way forward :)
