From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [take6 1/3] kevent: Core files. Date: Thu, 10 Aug 2006 12:22:35 +0400 Message-ID: <20060810082235.GA21025@2ka.mipt.ru> References: <11551105592821@2ka.mipt.ru> <11551105602734@2ka.mipt.ru> <20060809152127.481fb346.akpm@osdl.org> <20060810061433.GA4689@2ka.mipt.ru> <20060810001844.ff5e7429.akpm@osdl.org> <20060810075047.GB24370@2ka.mipt.ru> <20060810010254.3b52682f.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Cc: lkml , David Miller , Ulrich Drepper , netdev , Zach Brown Return-path: Received: from relay.2ka.mipt.ru ([194.85.82.65]:47299 "EHLO 2ka.mipt.ru") by vger.kernel.org with ESMTP id S1751469AbWHJIXK (ORCPT ); Thu, 10 Aug 2006 04:23:10 -0400 To: Andrew Morton Content-Disposition: inline In-Reply-To: <20060810010254.3b52682f.akpm@osdl.org> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Aug 10, 2006 at 01:02:54AM -0700, Andrew Morton (akpm@osdl.org) wrote: > > > Afaict this mmap function gives a user a free way of getting pinned memory. > > > What is the upper bound on the amount of memory which a user can thus > > > obtain? > > > > it is limited by maximum queue length which is 4k entries right now, so > > maximum number of paged here is 4k*40/page_size, i.e. about 40 pages on > > x86. > > Is that per user or per fd? If the latter that is, with the usual > RLIMIT_NOFILE, 160MBytes. 2GB with 64k pagesize. Problem ;) Per kevent fd. I have some ideas about better mmap ring implementation, which would dinamically grow it's buffer when events are added and reuse the same place for next events, but there are some nitpics unresolved yet. Let's not see there in next releases (no merge of course), until better solution is ready. I will change that area when other things are ready. -- Evgeniy Polyakov