From: Steven Sistare <steven.sistare@oracle.com>
To: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: "Jason Zeng" <jason.zeng@linux.intel.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Juan Quintela" <quintela@redhat.com>,
qemu-devel@nongnu.org,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>
Subject: Re: [PATCH V2 05/22] vl: memfd-alloc option
Date: Wed, 6 Jan 2021 11:36:51 -0500 [thread overview]
Message-ID: <d6c1b91e-9c49-3356-554d-39da53a11e16@oracle.com> (raw)
In-Reply-To: <20210105162708.GH724458@redhat.com>
On 1/5/2021 11:27 AM, Daniel P. Berrangé wrote:
> On Tue, Jan 05, 2021 at 07:41:53AM -0800, Steve Sistare wrote:
>> Allocate anonymous memory using memfd_create if the memfd-alloc option is
>> set.
>>
>> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
>> ---
>> exec.c | 38 ++++++++++++++++++++++++++++++--------
>> include/sysemu/sysemu.h | 1 +
>> qemu-options.hx | 11 +++++++++++
>> softmmu/vl.c | 4 ++++
>> trace-events | 1 +
>> 5 files changed, 47 insertions(+), 8 deletions(-)
>
>> diff --git a/qemu-options.hx b/qemu-options.hx
>> index 708583b..455b43b7 100644
>> --- a/qemu-options.hx
>> +++ b/qemu-options.hx
>> @@ -4094,6 +4094,17 @@ SRST
>> an unmigratable state.
>> ERST
>>
>> +#ifdef __linux__
>> +DEF("memfd-alloc", 0, QEMU_OPTION_memfd_alloc, \
>> + "-memfd-alloc allocate anonymous memory using memfd_create\n",
>> + QEMU_ARCH_ALL)
>> +#endif
>> +
>> +SRST
>> +``-memfd-alloc``
>> + Allocate anonymous memory using memfd_create (Linux only).
>> +ERST
>
> Do we really need a new arg for this ? It is already possible to request
> use of memfd for the guest RAM using
>
> -object memory-backend-memfd,id=ram-node0,size=NNNN
>
> this memory backend object framework was intended to remove the need to
> add new ad-hoc CLI args for controlling memory allocation.
Yes, I considered that, but there are other memory regions that cannot be controlled
by the command line but which must be preserved, such as vram, bios, and rom. If vram
is not preserved, parts of the screen will be blank until the user performs some action
which refreshes the display. bios and rom should be preserved rather than re-recreated
with potentially different contents from the firmware images in the updated qemu package.
However, your comment reminds me that I must add a few lines of code to preserve the
memory-backend-memfd.
- Steve
next prev parent reply other threads:[~2021-01-06 16:38 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 15:41 [PATCH V2 00/22] Live Update Steve Sistare
2021-01-05 15:41 ` [PATCH V2 01/22] as_flat_walk Steve Sistare
2021-01-05 15:41 ` [PATCH V2 02/22] qemu_ram_volatile Steve Sistare
2021-01-05 15:41 ` [PATCH V2 03/22] oslib: qemu_clr_cloexec Steve Sistare
2021-01-05 15:41 ` [PATCH V2 04/22] util: env var helpers Steve Sistare
2021-01-05 15:41 ` [PATCH V2 05/22] vl: memfd-alloc option Steve Sistare
2021-01-05 16:27 ` Daniel P. Berrangé
2021-01-06 16:36 ` Steven Sistare [this message]
2021-01-06 20:10 ` Paolo Bonzini
2021-01-06 21:19 ` Steven Sistare
2021-01-05 15:41 ` [PATCH V2 06/22] vl: add helper to request re-exec Steve Sistare
2021-01-05 15:41 ` [PATCH V2 07/22] cpr Steve Sistare
2021-01-05 15:41 ` [PATCH V2 08/22] cpr: QMP interfaces Steve Sistare
2021-01-05 15:41 ` [PATCH V2 09/22] cpr: HMP interfaces Steve Sistare
2021-01-05 15:41 ` [PATCH V2 10/22] pci: export functions for cpr Steve Sistare
2021-01-05 15:41 ` [PATCH V2 11/22] vfio-pci: refactor " Steve Sistare
2021-01-05 15:42 ` [PATCH V2 12/22] vfio-pci: cpr Steve Sistare
2021-01-05 15:42 ` [PATCH V2 13/22] vhost: reset vhost devices upon cprsave Steve Sistare
2021-01-05 15:42 ` [PATCH V2 14/22] chardev: cpr framework Steve Sistare
2021-01-05 15:42 ` [PATCH V2 15/22] chardev: cpr for simple devices Steve Sistare
2021-01-05 15:42 ` [PATCH V2 16/22] chardev: cpr for pty Steve Sistare
2021-01-05 15:42 ` [PATCH V2 17/22] chardev: socket accept subroutine Steve Sistare
2021-01-05 15:42 ` [PATCH V2 18/22] chardev: cpr for sockets Steve Sistare
2021-01-05 16:22 ` Daniel P. Berrangé
2021-01-05 16:35 ` Steven Sistare
2021-01-05 15:42 ` [PATCH V2 19/22] monitor: cpr support Steve Sistare
2021-01-05 15:42 ` [PATCH V2 20/22] cpr: only-cpr-capable option Steve Sistare
2021-01-05 15:42 ` [PATCH V2 21/22] cpr: maintainers Steve Sistare
2021-01-05 15:42 ` [PATCH V2 22/22] simplify savevm Steve Sistare
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