linux-kernel - Re: [PATCH] mm/mincore: allow for making sys

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Message-ID: <nycvar.YFH.7.76.1901162120000.6626@cbobk.fhfr.pm>
Date:   Wed, 16 Jan 2019 21:23:04 +0100 (CET)
From:   Jiri Kosina <jikos@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
cc:     Dominique Martinet <asmadeus@...ewreck.org>,
        Andy Lutomirski <luto@...capital.net>,
        Josh Snyder <joshs@...flix.com>,
        Dave Chinner <david@...morbit.com>,
        Matthew Wilcox <willy@...radead.org>,
        Jann Horn <jannh@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Michal Hocko <mhocko@...e.com>, Linux-MM <linux-mm@...ck.org>,
        kernel list <linux-kernel@...r.kernel.org>,
        Linux API <linux-api@...r.kernel.org>
Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged

On Thu, 17 Jan 2019, Linus Torvalds wrote:

> > So that seems to deal with mincore() in a reasonable way indeed.
> >
> > It doesn't unfortunately really solve the preadv2(RWF_NOWAIT), nor does it
> > provide any good answer what to do about it, does it?
> 
> As I suggested earlier in the thread, the fix for RWF_NOWAIT might be
> to just move the test down to after readahead.

So I've done some basic smoke testing (~2 hours of LTP+xfstests) on the 
kernel with the three topmost patches from

	https://git.kernel.org/pub/scm/linux/kernel/git/jikos/jikos.git/log/?h=pagecache-sidechannel

applied (also attaching to this mail), and no obvious breakage popped up.

So if noone sees any principal problem there, I'll happily submit it with 
proper attribution etc.

Thanks,

-- 
Jiri Kosina
SUSE Labs

View attachment "0001-Revert-Change-mincore-to-count-mapped-pages-rather-t.patch" of type "text/x-patch" (4248 bytes)

View attachment "0002-mm-mincore-make-mincore-more-conservative.patch" of type "text/x-patch" (2315 bytes)

View attachment "0003-mm-filemap-initiate-readahead-even-if-IOCB_NOWAIT-is.patch" of type "text/x-patch" (1368 bytes)