From: Michal Hocko <email@example.com> To: firstname.lastname@example.org Cc: Andrew Morton <email@example.com>, Alexey Dobriyan <firstname.lastname@example.org>, email@example.com, LKML <firstname.lastname@example.org>, Dan Williams <email@example.com>, David Rientjes <firstname.lastname@example.org>, Jan Kara <email@example.com> Subject: Re: [RFC PATCH 0/3] THP eligibility reporting via proc Date: Fri, 7 Dec 2018 11:55:54 +0100 [thread overview] Message-ID: <20181207105554.GX1286@dhcp22.suse.cz> (raw) In-Reply-To: <firstname.lastname@example.org> On Tue 20-11-18 11:35:12, Michal Hocko wrote: > Hi, > this series of three patches aims at making THP eligibility reporting > much more robust and long term sustainable. The trigger for the change > is a regression report  and the long follow up discussion. In short > the specific application didn't have good API to query whether a particular > mapping can be backed by THP so it has used VMA flags to workaround that. > These flags represent a deep internal state of VMAs and as such they should > be used by userspace with a great deal of caution. > > A similar has happened for  when users complained that VM_MIXEDMAP is > no longer set on DAX mappings. Again a lack of a proper API led to an > abuse. > > The first patch in the series tries to emphasise that that the semantic > of flags might change and any application consuming those should be really > careful. > > The remaining two patches provide a more suitable interface to address  > and provide a consistent API to query the THP status both for each VMA > and process wide as well. Are there any other comments on these? I haven't heard any pushback so far so I will re-send with RFC dropped early next week. > >  http://lkml.kernel.org/r/http://lkml.kernel.org/r/alpine.DEB.email@example.com >  http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz > -- Michal Hocko SUSE Labs
prev parent reply other threads:[~2018-12-07 10:55 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-20 10:35 Michal Hocko 2018-11-20 10:35 ` [RFC PATCH 1/3] mm, proc: be more verbose about unstable VMA flags in /proc/<pid>/smaps Michal Hocko 2018-11-20 10:51 ` Jan Kara 2018-11-20 11:41 ` Michal Hocko 2018-11-21 0:01 ` David Rientjes 2018-11-21 6:56 ` Michal Hocko 2018-11-20 18:32 ` Dan Williams 2018-11-21 7:05 ` Michal Hocko 2018-11-21 18:01 ` Mike Rapoport 2018-11-21 17:54 ` Mike Rapoport 2018-11-21 17:58 ` Michal Hocko 2018-11-23 13:47 ` Vlastimil Babka 2018-11-20 10:35 ` [RFC PATCH 2/3] mm, thp, proc: report THP eligibility for each vma Michal Hocko 2018-11-20 11:42 ` Michal Hocko 2018-11-23 15:07 ` Vlastimil Babka 2018-11-23 15:21 ` Michal Hocko 2018-11-23 15:24 ` Vlastimil Babka 2018-11-20 10:35 ` [RFC PATCH 3/3] mm, proc: report PR_SET_THP_DISABLE in proc Michal Hocko 2018-11-20 11:42 ` Michal Hocko 2018-11-23 15:49 ` Vlastimil Babka 2018-11-27 0:33 ` William Kucharski 2018-11-27 13:17 ` Michal Hocko 2018-11-27 14:50 ` William Kucharski 2018-11-27 16:25 ` Michal Hocko 2018-11-27 16:50 ` Vlastimil Babka 2018-11-27 17:06 ` William Kucharski 2018-12-07 10:55 ` Michal Hocko [this message]
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