From mboxrd@z Thu Jan 1 00:00:00 1970 From: mans@mansr.com (=?iso-8859-1?Q?M=E5ns_Rullg=E5rd?=) Date: Sat, 22 Oct 2011 14:13:55 +0100 Subject: [PATCH 0/3] ARM 4Kstacks: introduction In-Reply-To: (Ming Lei's message of "Sat, 22 Oct 2011 16:50:15 +0800") References: <4E9E0B71.9020708@am.sony.com> <1318983248.7569.5.camel@Joe-Laptop> <4E9E1944.80601@am.sony.com> <1500345.YeXPhIIHc5@wuerfel> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Ming Lei writes: > On Wed, Oct 19, 2011 at 6:51 PM, Arnd Bergmann wrote: >> On Tuesday 18 October 2011 17:26:44 Tim Bird wrote: >>> Even inside Sony, usage of 4K stacks is limited >>> to some very special cases, where memory is exceedingly >>> tight (we have one system with 4M of RAM). ?And we >>> don't mind lopping off features or coding around >>> problem areas to support our special case. >> >> I would imagine that in those cases, you can gain more by reducing the >> number of threads in the system. What is the highest number of >> concurrent threads that you expect in a limited use case with no >> networking or block devices? > > If system run for some time, sometimes it may be difficult for > memory allocator to allocate 2 continuous page frames even there are > many spare page frames in system because of > fragment issue, so the patch does make sense. Anyway, > it provides one option for user to apply 4k stack to avoid > such kind of process creation failure. Can't page migration be used in these situations? -- M?ns Rullg?rd mans at mansr.com