From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-api@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andres Lagar-Cavilla <andreslc@google.com>,
Dave Hansen <dave@sr71.net>, Paolo Bonzini <pbonzini@redhat.com>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Andy Lutomirski <luto@amacapital.net>,
Andrew Morton <akpm@linux-foundation.org>,
Sasha Levin <sasha.levin@oracle.com>,
Hugh Dickins <hughd@google.com>,
Peter Feiner <pfeiner@google.com>,
"\\\"Dr. David Alan Gilbert\\\"" <dgilbert@redhat.com>,
Christopher Covington <cov@codeaurora.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Android Kernel Team <kernel-team@android.com>,
Robert Love <rlove@google.com>,
Dmitry Adamushko <dmitry.adamushko@gmail.com>,
Neil Brown <neilb@suse.de>, Mike Hommey <mh@glandium.org>,
Taras Glek <tglek@mozilla.>
Subject: Re: [PATCH 08/17] mm: madvise MADV_USERFAULT
Date: Tue, 7 Oct 2014 13:36:45 +0300 [thread overview]
Message-ID: <20141007103645.GB30762@node.dhcp.inet.fi> (raw)
In-Reply-To: <1412356087-16115-9-git-send-email-aarcange@redhat.com>
On Fri, Oct 03, 2014 at 07:07:58PM +0200, Andrea Arcangeli wrote:
> MADV_USERFAULT is a new madvise flag that will set VM_USERFAULT in the
> vma flags. Whenever VM_USERFAULT is set in an anonymous vma, if
> userland touches a still unmapped virtual address, a sigbus signal is
> sent instead of allocating a new page. The sigbus signal handler will
> then resolve the page fault in userland by calling the
> remap_anon_pages syscall.
Hm. I wounder if this functionality really fits madvise(2) interface: as
far as I understand it, it provides a way to give a *hint* to kernel which
may or may not trigger an action from kernel side. I don't think an
application will behaive reasonably if kernel ignore the *advise* and will
not send SIGBUS, but allocate memory.
I would suggest to consider to use some other interface for the
functionality: a new syscall or, perhaps, mprotect().
--
Kirill A. Shutemov
--
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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2014-10-07 10:36 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-03 17:07 [PATCH 00/17] RFC: userfault v2 Andrea Arcangeli
2014-10-03 17:07 ` [PATCH 01/17] mm: gup: add FOLL_TRIED Andrea Arcangeli
2014-10-03 18:15 ` Linus Torvalds
2014-10-03 20:55 ` Paolo Bonzini
2014-10-03 17:07 ` [PATCH 02/17] mm: gup: add get_user_pages_locked and get_user_pages_unlocked Andrea Arcangeli
2014-10-03 17:07 ` [PATCH 03/17] mm: gup: use get_user_pages_unlocked within get_user_pages_fast Andrea Arcangeli
2014-10-03 17:07 ` [PATCH 04/17] mm: gup: make get_user_pages_fast and __get_user_pages_fast latency conscious Andrea Arcangeli
2014-10-03 18:23 ` Linus Torvalds
2014-10-06 14:14 ` Andrea Arcangeli
2014-10-03 17:07 ` [PATCH 05/17] mm: gup: use get_user_pages_fast and get_user_pages_unlocked Andrea Arcangeli
2014-10-03 17:07 ` [PATCH 06/17] kvm: Faults which trigger IO release the mmap_sem Andrea Arcangeli
2014-10-03 17:07 ` [PATCH 07/17] mm: madvise MADV_USERFAULT: prepare vm_flags to allow more than 32bits Andrea Arcangeli
2014-10-07 9:03 ` Kirill A. Shutemov
[not found] ` <1412356087-16115-8-git-send-email-aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-11-06 20:08 ` Konstantin Khlebnikov
2014-10-03 17:07 ` [PATCH 08/17] mm: madvise MADV_USERFAULT Andrea Arcangeli
2014-10-03 23:13 ` Mike Hommey
2014-10-06 17:24 ` Andrea Arcangeli
2014-10-07 10:36 ` Kirill A. Shutemov [this message]
2014-10-07 10:46 ` Dr. David Alan Gilbert
2014-10-07 10:52 ` [Qemu-devel] " Kirill A. Shutemov
2014-10-07 11:01 ` Dr. David Alan Gilbert
2014-10-07 11:30 ` Kirill A. Shutemov
2014-10-07 13:24 ` Andrea Arcangeli
2014-10-07 15:21 ` Kirill A. Shutemov
2014-10-03 17:07 ` [PATCH 09/17] mm: PT lock: export double_pt_lock/unlock Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 10/17] mm: rmap preparation for remap_anon_pages Andrea Arcangeli
2014-10-03 18:31 ` Linus Torvalds
2014-10-06 8:55 ` Dr. David Alan Gilbert
2014-10-06 16:41 ` Andrea Arcangeli
2014-10-07 12:47 ` Linus Torvalds
2014-10-07 14:19 ` Andrea Arcangeli
2014-10-07 15:52 ` Andrea Arcangeli
2014-10-07 15:54 ` Andy Lutomirski
[not found] ` <20141007155247.GD2342-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-10-07 16:13 ` Peter Feiner
[not found] ` <20141007141913.GC2342-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-10-07 16:56 ` Linus Torvalds
2014-10-07 17:07 ` Dr. David Alan Gilbert
2014-10-07 17:14 ` Paolo Bonzini
2014-10-07 17:25 ` Dr. David Alan Gilbert
2014-10-07 11:10 ` [Qemu-devel] " Kirill A. Shutemov
2014-10-07 13:37 ` Andrea Arcangeli
[not found] ` <1412356087-16115-1-git-send-email-aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-10-03 17:08 ` [PATCH 11/17] mm: swp_entry_swapcount Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 12/17] mm: sys_remap_anon_pages Andrea Arcangeli
2014-10-04 13:13 ` Andi Kleen
2014-10-06 17:00 ` Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 13/17] waitqueue: add nr wake parameter to __wake_up_locked_key Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 14/17] userfaultfd: add new syscall to provide memory externalization Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 15/17] userfaultfd: make userfaultfd_write non blocking Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 16/17] powerpc: add remap_anon_pages and userfaultfd Andrea Arcangeli
2014-10-03 17:08 ` [PATCH 17/17] userfaultfd: implement USERFAULTFD_RANGE_REGISTER|UNREGISTER Andrea Arcangeli
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20141007103645.GB30762@node.dhcp.inet.fi \
--to=kirill@shutemov.name \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=andreslc@google.com \
--cc=cov@codeaurora.org \
--cc=dave@sr71.net \
--cc=dgilbert@redhat.com \
--cc=dmitry.adamushko@gmail.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=kernel-team@android.com \
--cc=kvm@vger.kernel.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@amacapital.net \
--cc=mgorman@suse.de \
--cc=mh@glandium.org \
--cc=neilb@suse.de \
--cc=pbonzini@redhat.com \
--cc=pfeiner@google.com \
--cc=qemu-devel@nongnu.org \
--cc=riel@redhat.com \
--cc=rlove@google.com \
--cc=sasha.levin@oracle.com \
--cc=tglek@mozilla. \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).