From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 218436B00A0 for ; Wed, 20 Oct 2010 12:57:51 -0400 (EDT) Received: from hpaq7.eem.corp.google.com (hpaq7.eem.corp.google.com [172.25.149.7]) by smtp-out.google.com with ESMTP id o9KGvlkj026875 for ; Wed, 20 Oct 2010 09:57:49 -0700 Received: from pxi8 (pxi8.prod.google.com [10.243.27.8]) by hpaq7.eem.corp.google.com with ESMTP id o9KGvFLi030238 for ; Wed, 20 Oct 2010 09:57:45 -0700 Received: by pxi8 with SMTP id 8so1150199pxi.15 for ; Wed, 20 Oct 2010 09:57:45 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 20 Oct 2010 09:57:44 -0700 Message-ID: Subject: Re: TMPFS Maximum File Size From: Hugh Dickins Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Tharindu Rukshan Bamunuarachchi Cc: Christoph Lameter , linux-mm@kvack.org List-ID: On Wed, Oct 20, 2010 at 6:44 AM, Tharindu Rukshan Bamunuarachchi wrote: > > Is there any kind of file size limitation in TMPFS ? There is, but it should not be affecting you. In your x86_64 case, the tmpfs filesize limit should be slightly over 256GB. (There's no good reason for that limit when CONFIG_SWAP is not set, and it's then just a waste of memory on those swap vectors: I've long wanted to #iifdef CONFIG_SWAP them, but never put in the work to do so cleanly.) > Our application SEGFAULT inside write() after filling 70% of TMPFS > mount. (re-creatable but does not happen every time). I've no idea why that should be happening: I wonder if your case is actually triggering some memory corruption, in application or in kernel, that manifests in that way. But I don't quite understand what you're seeing either: a segfault in the write() library call of your libc? an EFAULT from the kernel's sys_write()? Hugh > > We are using 98GB TMPFS without swap device. i.e. SWAP is turned off. > Applications does not take approx. 20GB memory. > > we have Physical RAM of 128GB Intel x86 box running SLES 11 64bit. > We use Infiniband, export TMPFS over NFS and IBM GPFS in same box. > (hope those won't affect) > > Bit confused about "triple-indirect swap vector" ? > > Extracted from shmem.c .... > > /* > =C2=A0* The maximum size of a shmem/tmpfs file is limited by the maximum = size of > =C2=A0* its triple-indirect swap vector - see illustration at shmem_swp_e= ntry(). > =C2=A0* > =C2=A0* With 4kB page size, maximum file size is just over 2TB on a 32-bi= t kernel, > =C2=A0* but one eighth of that on a 64-bit kernel.=C2=A0 With 8kB page si= ze, maximum > =C2=A0* file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-b= it kernel, > =C2=A0* MAX_LFS_FILESIZE being then more restrictive than swap vector lay= out. > =C2=A0* > > Thankx a lot. > __ > Tharindu R Bamunuarachchi. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org