From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8666BC2BA83 for ; Thu, 13 Feb 2020 12:55:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5577C2168B for ; Thu, 13 Feb 2020 12:55:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5577C2168B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CBBC06B0538; Thu, 13 Feb 2020 07:55:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C6CCD6B0539; Thu, 13 Feb 2020 07:55:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B5AF66B053A; Thu, 13 Feb 2020 07:55:48 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0107.hostedemail.com [216.40.44.107]) by kanga.kvack.org (Postfix) with ESMTP id 9BFD16B0538 for ; Thu, 13 Feb 2020 07:55:48 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 42ABE824805A for ; Thu, 13 Feb 2020 12:55:48 +0000 (UTC) X-FDA: 76485100776.17.wash79_4fbb6dd79f50d X-HE-Tag: wash79_4fbb6dd79f50d X-Filterd-Recvd-Size: 4610 Received: from youngberry.canonical.com (youngberry.canonical.com [91.189.89.112]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Thu, 13 Feb 2020 12:55:47 +0000 (UTC) Received: from [95.91.247.236] (helo=wittgenstein) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1j2E1q-0008Or-C8; Thu, 13 Feb 2020 12:55:38 +0000 Date: Thu, 13 Feb 2020 13:55:37 +0100 From: Christian Brauner To: Brian Geffon , mtk.manpages@gmail.com Cc: Andrew Morton , "Michael S . Tsirkin" , Arnd Bergmann , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, Andy Lutomirski , Will Deacon , Andrea Arcangeli , Sonny Rao , Minchan Kim , Joel Fernandes , Yu Zhao , Jesse Barnes , Nathan Chancellor , Florian Weimer , "Kirill A . Shutemov" , linux-man@vger.kernel.org Subject: Re: [PATCH] mremap.2: Add information for MREMAP_DONTUNMAP. Message-ID: <20200213125537.n6zqqshtez7kxzlj@wittgenstein> References: <20200207201856.46070-1-bgeffon@google.com> <20200207202124.68949-1-bgeffon@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200207202124.68949-1-bgeffon@google.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This seems to miss hitting the correct mailing list: mtk.manpages@gmail.com linux-man@vger.kernel.org Christian On Fri, Feb 07, 2020 at 12:21:24PM -0800, Brian Geffon wrote: > Signed-off-by: Brian Geffon > --- > man2/mremap.2 | 27 ++++++++++++++++++++++++++- > 1 file changed, 26 insertions(+), 1 deletion(-) > > diff --git a/man2/mremap.2 b/man2/mremap.2 > index d73fb64fa..c660a45be 100644 > --- a/man2/mremap.2 > +++ b/man2/mremap.2 > @@ -26,7 +26,8 @@ > .\" 1996-04-12 Tom Bjorkholm > .\" Update for Linux 1.3.87 and later > .\" 2005-10-11 mtk: Added NOTES for MREMAP_FIXED; revised EINVAL text. > -.\" > +.\" 2020-02-05 Brian Geffon > +.\" Update for MREMAP_DONTUNMAP. > .TH MREMAP 2 2019-03-06 "Linux" "Linux Programmer's Manual" > .SH NAME > mremap \- remap a virtual memory address > @@ -129,6 +130,13 @@ If > is specified, then > .B MREMAP_MAYMOVE > must also be specified. > +.TP > +.BR MREMAP_DONTUNMAP " (since Linux ?.?)" > +This flag which must be used in conjuction with > +.B MREMAP_MAYMOVE > +remaps a mapping to a new address and it does not unmap the mapping at \fIold_address\fP. This flag can only be used with private anonymous mappings. Any access to the range specified at \fIold_address\fP after completion will result in a page fault. If a > +.BR userfaultfd (2) > +was registered on the mapping specified by \fIold_address\fP it will continue to watch that mapping for faults. > .PP > If the memory segment specified by > .I old_address > @@ -176,6 +184,8 @@ a value other than > .B MREMAP_MAYMOVE > or > .B MREMAP_FIXED > +or > +.B MREMAP_DONTUNMAP > was specified in > .IR flags ; > .IP * > @@ -197,9 +207,14 @@ and > .IR old_size ; > .IP * > .B MREMAP_FIXED > +or > +.B MREMAP_DONTUNMAP > was specified without also specifying > .BR MREMAP_MAYMOVE ; > .IP * > +.B MREMAP_DONTUNMAP > +was specified with an \fIold_address\fP that was not private anonymous; > +.IP * > \fIold_size\fP was zero and \fIold_address\fP does not refer to a > shareable mapping (but see BUGS); > .IP * > @@ -209,10 +224,20 @@ flag was not specified. > .RE > .TP > .B ENOMEM > +Not enough memory was available to complete the operation. > +Possible causes are: > +.RS > +.IP * 3 > The memory area cannot be expanded at the current virtual address, and the > .B MREMAP_MAYMOVE > flag is not set in \fIflags\fP. > Or, there is not enough (virtual) memory available. > +.IP * > +.B MREMAP_DONTUNMAP > +was used without > +.B MREMAP_FIXED > +causing a new mapping to be created that would exceed the virtual memory available or it would exceed the maximum number of allowed mappings. > +.RE > .SH CONFORMING TO > This call is Linux-specific, and should not be used in programs > intended to be portable. > -- > 2.25.0.341.g760bfbb309-goog >