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To: Matthew Wilcox , Uladzislau Rezki CC: Kefeng Wang , , , , , References: <57f9eca2-effc-3a9f-932b-fd37ae6d0f87@huawei.com> <92768fc4-4fe0-f74a-d61c-dde0eb64e2c0@huawei.com> <76995749-1c2e-4f78-9aac-a4bff4b8097f@huawei.com> From: zuoze In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.186] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemg500008.china.huawei.com (7.202.181.45) X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 30016100003 X-Stat-Signature: s6ts9st9o8zcdmre6mmjjswqfwbxfisa X-Rspam-User: X-HE-Tag: 1733276285-270514 X-HE-Meta: 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 Tat8n2bF RJKAJ4Ed8R9qgDOVwpCBJi7hfRD0P4FBqekgZ6Grng4/BDBMH8e3J5KovS2KB1S8umJ2nudaqydX4oW1R2l+OKrD2EJMviurt2Ikr999Y3fS/jBGIRwFc5ip1q0zJquzGQFE7/O30apunIoz7o4bDCLfUDZujRkK7/Poj X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2024/12/4 3:56, Matthew Wilcox 写道: > On Tue, Dec 03, 2024 at 08:02:26PM +0100, Uladzislau Rezki wrote: > > I think there are a few other things we can try here. > > First, if the copy is small (and I still don't have an answer to that > ...), we can skip the vmalloc lookup if the copy doesn't cross a page > boundary. > large data packet. > Second, we could try storing this in a maple tree rather than an rbtree. > That gives us RCU protected lookups rather than under a spinlock. > > It might even be worth going to a rwlock first, in case the problem is > that there's severe lock contention. > > But I've asked for data on spinlock contention and not received an > answer on that either, so I don't know what to suggest. Thank you very much for your suggestions. We will check the spinlock contention in the future. > > Anyway, NACK to the original patch; that's just a horrible idea. >