From: Peter Xu <peterx@redhat.com>
To: Chuang Xu <xuchuangxclwt@bytedance.com>
Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, quintela@redhat.com,
pbonzini@redhat.com, david@redhat.com, philmd@linaro.org,
zhouyibo@bytedance.com
Subject: Re: [PATCH v7 4/6] memory: Add sanity check in address_space_to_flatview
Date: Fri, 10 Mar 2023 09:56:52 -0500 [thread overview]
Message-ID: <ZAtFNB5RaU5ywCnY@x1n> (raw)
In-Reply-To: <20230310022425.2992472-5-xuchuangxclwt@bytedance.com>
On Fri, Mar 10, 2023 at 10:24:23AM +0800, Chuang Xu wrote:
> Before using any flatview, sanity check whether BQL or rcu is held. And
> if we're during a memory region transaction, try to immediately update
> mappings, or the map can be invalid.
Sorry I didn't read into details in the previous version. This subject and
commit message all need update. It's not only about sanity anymore.
We need to state the major change to address_space_to_flatview() to allow
triggering do_commit() during a very large memory transaction, also on why
you did it.
IMHO it's because we find it's beneficial for speeding up vm load if wrap
the vm load into a whole memory transaction. The whole point is vm load
contains far more memory updates than referencing to a specific address
space / flatview, hence this nested do_commit should logically only be
triggered in a few spots during vm load.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2023-03-10 14:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-10 2:24 [PATCH v7 0/6] migration: reduce time of loading non-iterable vmstate Chuang Xu
2023-03-10 2:24 ` [PATCH v7 1/6] memory: Reference as->current_map directly in memory commit Chuang Xu
2023-03-14 11:25 ` David Edmondson
2023-03-10 2:24 ` [PATCH v7 2/6] rcu: Introduce rcu_read_is_locked() Chuang Xu
2023-03-10 14:50 ` Peter Xu
2023-03-10 2:24 ` [PATCH v7 3/6] memory: Introduce memory_region_transaction_do_commit() Chuang Xu
2023-03-10 14:51 ` Peter Xu
2023-03-13 2:53 ` Chuang Xu
2023-03-10 2:24 ` [PATCH v7 4/6] memory: Add sanity check in address_space_to_flatview Chuang Xu
2023-03-10 14:56 ` Peter Xu [this message]
2023-03-10 2:24 ` [PATCH v7 5/6] migration: Reduce time of loading non-iterable vmstate Chuang Xu
2023-03-10 14:58 ` Peter Xu
2023-03-16 10:46 ` Juan Quintela
2023-03-10 2:24 ` [PATCH v7 6/6] memory: Introduce address_space_to_flatview_rcu() Chuang Xu
2023-03-10 15:08 ` Peter Xu
2023-03-13 8:38 ` Chuang Xu
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