From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Date: Wed, 12 Aug 2009 02:39:56 +0000 Subject: Re: [RFC Patch 1/2] kexec: show memory info in /proc/iomem Message-Id: List-Id: References: <20090811104144.5154.77871.sendpatchset@localhost.localdomain> <4A82182C.1080501@redhat.com> <4A8225DB.8040008@redhat.com> In-Reply-To: <4A8225DB.8040008@redhat.com> (Amerigo Wang's message of "Wed\, 12 Aug 2009 10\:15\:55 +0800") MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Amerigo Wang Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Neil Horman , Andi Kleen , akpm@linux-foundation.org, Ingo Molnar Amerigo Wang writes: 2> Eric W. Biederman wrote: >> Amerigo Wang writes: >> >> >>>> Nacked-by: "Eric W. Biederman" >>>> >>>> We can inspect the image we are going to load to get this information. >>>> In fact /sbin/kexec already inspects the image we are going to load >>>> to get this information. Putting this in the kernel adds kernel >>>> complexity for no gain. >>>> >>> /sbin/kexec is supported to know this, of course. But this is not for >>> /sbin/kexec, this is for user (or other programs) to observe the memory >>> information, so that he can know the memory he reserved is too much or not. >>> >> >> >>> Without this, it is a little hard to use patch 2/2. >>> >> >> So add on option to /sbin/kexec. >> > > This can be another choice. >> Furthermore none of this does a good job of predicting how much >> memory /sbin/fsck will require to check the filesystem before we >> write a crash dump. >> > > No one actually knows this without testing... But if 128M on x86 is still not > enough, that is probably a bug of fsck, not our fault. x86 covers a very large range of hardware. Some of it nearly as large as the big ia64 machines. So why would ia64 require significantly more memory than x86? Eric