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Biederman" Cc: Josh Triplett , Kees Cook , Andrew Morton , Adrian Reber , LKML , Oleg Nesterov , Pavel Emelyanov , Andrei Vagin , Hendrik Brueckner , Linux Containers Subject: Re: [PATCH] kconfig: remove EXPERT from CHECKPOINT_RESTORE Message-ID: <20180714201957.GB8842@uranus> References: <20180712130733.11510-1-adrian@lisas.de> <87sh4o5s82.fsf@xmission.com> <20180713135541.7ada72437862c32f4563a9a8@linux-foundation.org> <87pnzpvdtd.fsf@xmission.com> <20180714191030.GA17877@localhost> <871sc5vc7n.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <871sc5vc7n.fsf@xmission.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 14, 2018 at 02:39:24PM -0500, Eric W. Biederman wrote: > Josh Triplett writes: > > > On Sat, Jul 14, 2018 at 02:04:46PM -0500, Eric W. Biederman wrote: > >> For a config option that no one has come forward with an actual real > >> world use case for disabling, that cost seems much too high. > > > > The real-world use case is precisely as stated: code size, both storage > > and RAM. > > That is theoretical. Which platform will break or feel distressed if we > make it unconditional. That is real world. > > > I regularly encounter systems I'd *like* to put Linux in that have > > around 1MB of storage and 1MB of RAM, or even less. > > Yes. There is so little code behind CONFIG_CHECKPOINT_RESTART that it > won't help with that. > > But if minification is the actual requirement for disabling > CONFIG_CHECKPOINT_RESTART than CONFIG_CHECKPIONT_RESTART is properly > behind expert and it needs to be default y instead of default n. I happened to miss this thread, sorry. So as far as I remember it was me who introduced this option in first place, and initially I placed it under expert so it won't be enabled by default. Lately we found that some of functionality introduced for criu sake actually pretty convenient for other tools (for example vmflags reported in procfs) so we dropped CONFIG_ option out for such blocks and merged them into kernel directly. I won't mind if left is merged into the kernel, there should not be that many places.