From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 12 Apr 2018 13:52:17 +0200 From: Michal Hocko To: Vlastimil Babka Cc: Roman Gushchin , linux-mm@kvack.org, Andrew Morton , Alexander Viro , Johannes Weiner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Linux API Subject: Re: [PATCH 1/3] mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES Message-ID: <20180412115217.GC23400@dhcp22.suse.cz> References: <20180305133743.12746-1-guro@fb.com> <20180305133743.12746-2-guro@fb.com> <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz> <20180411135624.GA24260@castle.DHCP.thefacebook.com> <46dbe2a5-e65f-8b72-f835-0210bc445e52@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46dbe2a5-e65f-8b72-f835-0210bc445e52@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: On Thu 12-04-18 08:52:52, Vlastimil Babka wrote: > On 04/11/2018 03:56 PM, Roman Gushchin wrote: > > On Wed, Apr 11, 2018 at 03:16:08PM +0200, Vlastimil Babka wrote: [...] > >> With that in mind, can we at least for now put the (manually maintained) > >> byte counter in a variable that's not directly exposed via /proc/vmstat, > >> and then when printing nr_slab_reclaimable, simply add the value > >> (divided by PAGE_SIZE), and when printing nr_slab_unreclaimable, > >> subtract the same value. This way we would be simply making the existing > >> counters more precise, in line with their semantics. > > > > Idk, I don't like the idea of adding a counter outside of the vm counters > > infrastructure, and I definitely wouldn't touch the exposed > > nr_slab_reclaimable and nr_slab_unreclaimable fields. Why? > We would be just making the reported values more precise wrt reality. I was suggesting something similar in an earlier discussion. I am not really happy about the new exposed counter either. It is just arbitrary by name yet very specific for this particular usecase. What is a poor user supposed to do with the new counter? Can this be used for any calculations? -- Michal Hocko SUSE Lab