On Tue, 27 Aug 2024 10:29:11 +0800 Hailong Liu <hailong.liu@xxxxxxxx> wrote: > On Tue, 27. Aug 14:18, Barry Song wrote: > > On Tue, Aug 27, 2024 at 2:13 PM Hailong Liu <hailong.liu@xxxxxxxx> wrote: > > > > > > On Mon, 26. Aug 09:37, Lokesh Gidra wrote: > > > > > > > > IMHO, within LRU_INACTIVE_FILE, MADV_FREE'ed pages should be > > > > prioritized for reclamation over file ones. > > > > > > > > > > > > > > > > Adding Lokesh. > > > > > Lokesh, could you please comment on the reasoning behind the above > > > > > mentioned change? > > > > > > > > Adding Nicolas as well, in case he wants to add something. > > > IMHO, lruvec_add_folio is enough. if lruvec_add_folio_tail why not use > > > MADV_DONTNEED instead? In MM the reclaim policy prefer to reclaim file cache, if > > > MADV_FREE'd pages directly add to the tail, they might be reclaimed instantly. > > > Also the benefit of workingset_refault_file cannot be convinced for me. > > > > My understanding is that MADV_DONTNEED will immediately free the memory, > > whereas MADV_FREE will release memory only under memory pressure. If > > memory pressure is low, the anonymous memory may still be gotten back > > without causing page faults. This might be what Lokesh is aiming to achieve. > > > Hmm, IIUC, for the reason of watermark, the kswapd would do reclamation without > memory pressure. I worried here is that the madv_free'd pages reclaimed too fast > if add to tail. I'm not seeing much clarity on whether we should merge this change. I think I'll drop this version - let's please revisit after -rc1.
