From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.2 \(3445.5.20\)) Subject: Re: [RFC PATCH v2 2/2] Architecture defined limit on memory region random shift. From: Ilya Smith In-Reply-To: <20180322135448.046ada120ecd1ab3dd8f94aa@linux-foundation.org> Date: Fri, 23 Mar 2018 20:49:03 +0300 Content-Transfer-Encoding: 8BIT Message-ID: <548B6BB8-FD6F-4F8D-B67F-2809305C617D@gmail.com> References: <1521736598-12812-1-git-send-email-blackzert@gmail.com> <1521736598-12812-3-git-send-email-blackzert@gmail.com> <20180322135448.046ada120ecd1ab3dd8f94aa@linux-foundation.org> Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: Message-ID: <20180323174903.QdSXClnKYU37uvlrsVCdZGgsGhUJDP04u_WTH0uOOQA@z> List-Archive: List-Post: To: Andrew Morton Cc: rth@twiddle.net, ink@jurassic.park.msu.ru, mattst88@gmail.com, vgupta@synopsys.com, linux@armlinux.org.uk, tony.luck@intel.com, fenghua.yu@intel.com, jhogan@kernel.org, ralf@linux-mips.org, jejb@parisc-linux.org, deller@gmx.de, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, nyc@holomorphy.com, viro@zeniv.linux.org.uk, arnd@arndb.de, gregkh@linuxfoundation.org, deepa.kernel@gmail.com, mhocko@suse.com, hughd@google.com, kstewart@linuxfoundation.org, pombredanne@nexb.com, steve.capper@arm.com, punit.agrawal@arm.com, paul.burton@mips.com, aneesh.kumar@linux.vnet.ibm.com, npiggin@gmail.com, keescook@chromium.org, bhsharma@redhat.com, riel@redhat.com, nitin.m.gupta@oracle.com, kirill.shutemov@linux.intel.com, dan.j.williams@intel.com, jack@suse.cz, ross.zwisler@linux.intel.com, jglisse@redhat.com, willy@infradead.org, aarcange@redhat.com, oleg@redhat.com, linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org List-ID: > On 22 Mar 2018, at 23:54, Andrew Morton wrote: > > > Please add changelogs. An explanation of what a "limit on memory > region random shift" is would be nice ;) Why does it exist, why are we > doing this, etc. Surely there's something to be said - at present this > is just a lump of random code? > > > Sorry, my bad. The main idea of this limit is to decrease possible memory fragmentation. This is not so big problem on 64bit process, but really big for 32 bit processes since may cause failure memory allocation. To control memory fragmentation and protect 32 bit systems (or architectures) this limit was introduce by this patch. It could be also moved to CONFIG_ as well.