[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v3 1/2] x86/mm: rename FLUSH_FORCE_IPI to FLUSH_NO_ASSIST
- To: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Wed, 25 May 2022 13:14:20 +0200
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=3ynjWuKvzvrgYqBsbeVJslEQHd2T5p+jjmq3xYWfbf0=; b=mTTiPHKnAa9BRDBbqrGTn/pn13kadYmhXx13p3t2FUkkTJWh/xb0H1Xwx+J56QhyPnP7AqUv9a8ylm4QU7nJrYDDHBymQSFfkEKRCGh1c1IzHUbfYKDtCCpwienSywrtVBsgtQLKUilxWNLDUYaQ+3QLaE+mmZ8hfWMQ1cEWPXT4+RoLdXF0xmxYnOXwao3HWh3rtpS9oFndqTxxyzi9DF8JMaeGfSr8bdOSmRYYLPnLZkFoB2zNlAAKk3+HQQdluouGBQjgFE6HQB8AxH3FlfYgLpjV+yxR/WCxQOY00MfHz+IytOEpMYWUs/QmLeXGniAYht5YBCYzLpEiM5OLwA==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=mYlD14nYrGP7zYs8h+RtNgTtR4BoBOLwxt6L65eAFAshXwVkM/CnFq/CQjMUByoZcmT6mSBmZpwT/7rsULlQAPYnyfLScwHCJeUTY2u7jJOC2Ew3X0iahcjIQ5k/c+YymiFIXPjT9Fvwmx3KNHwqJ4+WLHo5nGy9imfni8GS/4aBAT8OdzCLQjxoGYLwJQEHFVEcE5Q84k0kzwszslePJ4qHeF9AFGGWfXjThvDURog3OKg3wCfPA40MTt/+v1X8i9WElsujQqJD+7sElsXHWaNEfnleWfxqKw4zzFLdEiSzRXC0aPKtc4aFd5D/QxT3/Y54Ohimt3vRi6/WFzw8Sw==
- Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com;
- Cc: Wei Liu <wl@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Roger Pau Monne <roger.pau@xxxxxxxxxx>
- Delivery-date: Wed, 25 May 2022 11:14:30 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 25.05.2022 12:52, Andrew Cooper wrote:
> On 25/05/2022 09:13, Roger Pau Monne wrote:
>> Rename the flag to better note that it's not actually forcing any IPIs
>> to be issued if none is required, but merely avoiding the usage of TLB
>> flush assistance (which itself can avoid the sending of IPIs to remote
>> processors).
>>
>> No functional change expected.
>>
>> Requested-by: Jan Beulich <jbeulich@xxxxxxxx>
>> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>> ---
>> Changes since v2:
>> - New in this version.
>
> :( This needs reverting.
>
> It is specific to IPIs, because of our current choice of algorithm for
> freeing pagetables.
>
> "no assist" excludes ipi-helper hypercalls which invoke
> INVALIDATE_TLB_VECTOR. Such hypercalls do exist and specifically would
> be improvement that we ought to use.
>
> Furthermore, we do want to work around the limitation that created
> FLUSH_FORCE_IPI, because we absolutely do want to be able to use
> hypercalls/remote TLB flushing capabilities when available.
>
> I accept that FORCE_IPI perhaps isn't a perfect name, but it's a whole
> lot less bad than NO_ASSIST.
But FORCE_IPI has caused actual confusion while reviewing patch 2.
If NO_ASSIST doesn't suit you and FORCE_IPI is also wrong, can you
suggest a better name fitting both aspects?
Jan
|
