linux-kernel - Re: [PATCH v3] xen: speed up grant-table reclaim

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0a05588e-68d3-1550-4c21-e282f4d66060@suse.com>
Date:   Tue, 4 Jul 2023 09:02:22 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Demi Marie Obenour <demi@...isiblethingslab.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
        Jan Beulich <JBeulich@...e.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:     Xen developer discussion <xen-devel@...ts.xenproject.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        stable@...r.kernel.org
Subject: Re: [PATCH v3] xen: speed up grant-table reclaim

On 27.06.23 19:22, Demi Marie Obenour wrote:
> When a grant entry is still in use by the remote domain, Linux must put
> it on a deferred list.  Normally, this list is very short, because
> the PV network and block protocols expect the backend to unmap the grant
> first.  However, Qubes OS's GUI protocol is subject to the constraints
> of the X Window System, and as such winds up with the frontend unmapping
> the window first.  As a result, the list can grow very large, resulting
> in a massive memory leak and eventual VM freeze.
> 
> To partially solve this problem, make the number of entries that the VM
> will attempt to free at each iteration tunable.  The default is still
> 10, but it can be overridden at compile-time (via Kconfig), boot-time
> (via a kernel command-line option), or runtime (via sysfs).

You are still mentioning Kconfig.

For the sysfs entry you should add something under Documentation/ABI. Sorry
I didn't spot this omission previously.


Juergen

Download attachment "OpenPGP_0xB0DE9DD628BF132F.asc" of type "application/pgp-keys" (3099 bytes)

Download attachment "OpenPGP_signature" of type "application/pgp-signature" (496 bytes)