From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlastimil Babka Subject: Re: [PATCH V5] Allow compaction of unevictable pages Date: Wed, 18 Mar 2015 15:40:38 +0100 Message-ID: <55098E66.7030609@suse.cz> References: <1426267597-25811-1-git-send-email-emunson@akamai.com> <550332CE.7040404@redhat.com> <20150313190915.GA12589@akamai.com> <20150313201954.GB28848@dhcp22.suse.cz> <5506ACEC.9010403@suse.cz> <20150316134956.GA15324@akamai.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150316134956.GA15324-JqFfY2XvxFXQT0dZR+AlfA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Eric B Munson Cc: Michal Hocko , Rik van Riel , Andrew Morton , Thomas Gleixner , Christoph Lameter , Peter Zijlstra , Mel Gorman , David Rientjes , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux API List-Id: linux-api@vger.kernel.org On 03/16/2015 02:49 PM, Eric B Munson wrote: > On Mon, 16 Mar 2015, Vlastimil Babka wrote: > >> [CC += linux-api@] >> >> Since this is a kernel-user-space API change, please CC linux-api@. >> The kernel source file Documentation/SubmitChecklist notes that all >> Linux kernel patches that change userspace interfaces should be CCed >> to linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, so that the various parties who are >> interested in API changes are informed. For further information, see >> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.kernel.org_doc_man-2Dpages_linux-2Dapi-2Dml.html&d=AwIC-g&c=96ZbZZcaMF4w0F4jpN6LZg&r=aUmMDRRT0nx4IfILbQLv8xzE0wB9sQxTHI3QrQ2lkBU&m=GUotTNnv26L0HxtXrBgiHqu6kwW3ufx2_TQpXIA216c&s=IFFYQ7Zr-4SIaF3slOZqiSP_noyva42kCwVRxxDm5wo&e= > > Added to the Cc list, thanks. > >> >> >> On 03/13/2015 09:19 PM, Michal Hocko wrote: >>> On Fri 13-03-15 15:09:15, Eric B Munson wrote: >>>> On Fri, 13 Mar 2015, Rik van Riel wrote: >>>> >>>>> On 03/13/2015 01:26 PM, Eric B Munson wrote: >>>>> >>>>>> --- a/mm/compaction.c >>>>>> +++ b/mm/compaction.c >>>>>> @@ -1046,6 +1046,8 @@ typedef enum { >>>>>> ISOLATE_SUCCESS, /* Pages isolated, migrate */ >>>>>> } isolate_migrate_t; >>>>>> >>>>>> +int sysctl_compact_unevictable; >> >> A comment here would be useful I think, as well as explicit default >> value. Maybe also __read_mostly although I don't know how much that >> matters. > > I am going to sit on V6 for a couple of days incase anyone from rt wants > to chime in. But these will be in V6. > >> >> I also wonder if it might be confusing that "compact_memory" is a >> write-only trigger that doesn't even show under "sysctl -a", while >> "compact_unevictable" is a read/write setting. But I don't have a >> better suggestion right now. > > Does allow_unevictable_compaction sound better? It feels too much like For sorting purposes, maybe compact_unevictable_allowed? > variable naming conventions from other languages which seems to > encourage verbosity to me, but does indicate a difference from > compact_memory. If it sounds too awkward/long and nobody else has better suggestion, then just keep it as "compact_unevictable".