Hi Suren, On Wed, Aug 01, 2018 at 02:56:27PM -0700, Suren Baghdasaryan wrote: > On Wed, Aug 1, 2018 at 8:19 AM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > /* > > - * The unsigned subtraction here gives an accurate distance > > - * across inactive_age overflows in most cases. > > + * Calculate the refault distance > > * > > - * There is a special case: usually, shadow entries have a > > - * short lifetime and are either refaulted or reclaimed along > > - * with the inode before they get too old. But it is not > > - * impossible for the inactive_age to lap a shadow entry in > > - * the field, which can then can result in a false small > > - * refault distance, leading to a false activation should this > > - * old entry actually refault again. However, earlier kernels > > - * used to deactivate unconditionally with *every* reclaim > > - * invocation for the longest time, so the occasional > > - * inappropriate activation leading to pressure on the active > > - * list is not a problem. > > + * The unsigned subtraction here gives an accurate distance > > + * across inactive_age overflows in most cases. There is a > > + * special case: usually, shadow entries have a short lifetime > > + * and are either refaulted or reclaimed along with the inode > > + * before they get too old. But it is not impossible for the > > + * inactive_age to lap a shadow entry in the field, which can > > + * then can result in a false small refault distance, leading > > "which can then can" - please remove one of the "can". Good catch, will fix.
