From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f173.google.com (mail-qc0-f173.google.com [209.85.216.173]) by kanga.kvack.org (Postfix) with ESMTP id E3C926B0069 for ; Wed, 1 Oct 2014 13:17:30 -0400 (EDT) Received: by mail-qc0-f173.google.com with SMTP id x13so693351qcv.4 for ; Wed, 01 Oct 2014 10:17:30 -0700 (PDT) Received: from omr2.cc.vt.edu (omr2.cc.ipv6.vt.edu. [2001:468:c80:2105:0:24d:7091:8b9c]) by mx.google.com with ESMTPS id m6si2669793qaa.127.2014.10.01.10.17.29 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 01 Oct 2014 10:17:30 -0700 (PDT) Subject: Re: [PATCH v11 00/21] Add support for NV-DIMMs to ext4 In-Reply-To: Your message of "Wed, 01 Oct 2014 11:45:47 -0400." From: Valdis.Kletnieks@vt.edu References: <1411677218-29146-1-git-send-email-matthew.r.wilcox@intel.com> <15705.1412070301@turing-police.cc.vt.edu> <20140930144854.GA5098@wil.cx> <123795.1412088827@turing-police.cc.vt.edu> <20140930160841.GB5098@wil.cx> <15704.1412109476@turing-police.cc.vt.edu> <62749.1412113956@turing-police.cc.vt.edu> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1412183841_2347P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Wed, 01 Oct 2014 13:17:21 -0400 Message-ID: <9487.1412183841@turing-police.cc.vt.edu> Sender: owner-linux-mm@kvack.org List-ID: To: Jeff Moyer Cc: Andreas Dilger , Matthew Wilcox , Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org --==_Exmh_1412183841_2347P Content-Type: text/plain; charset=us-ascii On Wed, 01 Oct 2014 11:45:47 -0400, Jeff Moyer said: > This sounds an awful lot like posix_fadvise' POSIX_FADV_NOREUSE flag. Gaah. Premature click. man posix_fadvise says this: In kernels before 2.6.18, POSIX_FADV_NOREUSE had the same semantics as POSIX_FADV_WILLNEED. This was probably a bug; since kernel 2.6.18, this flag is a no-op. and mm/fadvise.c says this: switch (advice) { case POSIX_FADV_NORMAL: f.file->f_ra.ra_pages = bdi->ra_pages; spin_lock(&f.file->f_lock); f.file->f_mode &= ~FMODE_RANDOM; spin_unlock(&f.file->f_lock); ... */ force_page_cache_readahead(mapping, f.file, start_index, nrpages); break; case POSIX_FADV_NOREUSE: break; case POSIX_FADV_DONTNEED: if (!bdi_write_congested(mapping->backing_dev_info)) __filemap_fdatawrite_range(mapping, offset, endbyte, WB_SYNC_NONE); /* First and last FULL page! */ So... not much interface there, actually. One wonders if removing the 'break;' and allowing a fall-through would actually be an improvement.... --==_Exmh_1412183841_2347P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Exmh version 2.5 07/13/2001 iQIVAwUBVCw3IQdmEQWDXROgAQIZaw/+NXbC9mR/tCaZSx+zdxrhOArKos2TcUu3 jqJTFEeK7794NGIlYb/OaELCoSyQcYNoffo76/Si4d2Pxf5limmQJOmaNiuNzdse ZpaxBxp44yg+urLP0KY/flSdxd7gCq47I1kwCxwdw6Sbx2YJF1nX51m1PTjVw3dy 4xijAyMVgMpCahFlbC2Ita5HO0+++eqDEYq7qLvztPWS9J+cq0gMGZKWWaiuvDq0 tTxzh3pi+G/aCppZnrIEM+tnAaEga+wyluZZ4TOQz4IbHBIEIt988PA+SLB8unTU 1gUWrla3upVenlAv8kWhSdZTRVkQcnlgY+HE1UY1DXfeBCTGIYXueF9d81sQhuvf fCmOftbJna3eNf1QlMc6oSm4XMmczQ1SysFi2B0yqe6DoxGoQuoTV/QbPAIKmO6s u/DuRxzsHuZOhGPob32cMcMT0ALXUvh5OfPFHs5wbd1N9qwx2im4lYPRh25BIqR/ ZNuGzXJ/tHDC5s55drYKtpQNgE1yFDu/hSlAEAtV4IqYXDdfRwWhQxFJKFrpe6E9 D/cTIb25nXWISQ8io5EJahNyeboiPac5X82OMs7uYHDTChIWtoce3+Q1U97Gz2/C +S3rh2MroSF6x+zQ4xbhBwjhQ8x7BtniUdGGsIObTArZJZVS7bY636ksev2j/FcY 0d/neydDOU4= =BMzR -----END PGP SIGNATURE----- --==_Exmh_1412183841_2347P-- -- 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