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bh=n2M+9ZjTzGPpNEj89SkqrnJtVEb8EvbjHFOGwlS/Hlc=; b=taEdn4WIm5bBlZx1dsENbpxFU7hSIW/QN/Tq7OpYBIKyAsqsdi6oYMKOspZzhM0nE1vkB6 fxfTRS1596hW9a3KQU6CEoVmzntnz3HxSg7AB19MSq7HXapKQqEQ5UZqhjjC8FW65QXGxt LzZKx/Ke1IwoB45LiH9eSp6xR+YcCvE/6hYCWZRxgPtWT+nW0/p7YOI1yFlauCen5yjBsw 6rREP19ov1r9Ijlwq8hHokQ1FDboJfpjBhMAp7pRM+u9tmvIsiKu+EY3C8fH9lm48495ym SNLG8rvprpmLiIxBTsAZ/g5uo2tZda7NqvDI0TWG8efaen8d2uSRRV4UTaLIpw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1684226647; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=n2M+9ZjTzGPpNEj89SkqrnJtVEb8EvbjHFOGwlS/Hlc=; b=uBHbcQ+EM/2f1WC9i1Bn9WYA5fJMvZEk0SVfbq0tDVlLVt1X2RHjbYo4pIOB8cTvn/iZgC O0tVSf+RKw6CnvAg== To: "Russell King (Oracle)" Cc: Andrew Morton , linux-mm@kvack.org, Christoph Hellwig , Uladzislau Rezki , Lorenzo Stoakes , Peter Zijlstra , Baoquan He , John Ogness , linux-arm-kernel@lists.infradead.org, Mark Rutland , Marc Zyngier , x86@kernel.org Subject: Re: Excessive TLB flush ranges In-Reply-To: References: <87a5y5a6kj.ffs@tglx> <87353x9y3l.ffs@tglx> <87zg658fla.ffs@tglx> <87r0rg93z5.ffs@tglx> Date: Tue, 16 May 2023 10:44:07 +0200 Message-ID: <87cz308y3s.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Stat-Signature: mn38ys9r43xq9dqhwfs6gw84rgaotso9 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9C3BC14000A X-Rspam-User: X-HE-Tag: 1684226649-299788 X-HE-Meta: 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 Gb/ekvrJ HXXNFoDj2wt6Ew63FIkLDAHoB0N4kda/YKW1TQ+Z3ndRQ3QCbWzkEu5hd2iPTJPAYhVq5ExB+CM6X1qc= 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: On Tue, May 16 2023 at 09:19, Russell King wrote: > On Tue, May 16, 2023 at 08:37:18AM +0200, Thomas Gleixner wrote: >> void flush_tlb_kernel_vas(struct list_head *list, unsigned int num_entries): >> >> So that an architecture can decide whether it's worth to do walk the >> entries or whether it resorts to a flush all. > > Is "num_entries" what an arch would want to use? How would it use that? > It doesn't tell an arch whether there is a large range of many list > entries, or a single entry covering a large range. Does it matter? The total number of entries to flush is what accumulates and at some architecture specific threshold that becomes more expensive than a full flush, independent of the range of the individual list entries, no? Thanks, tglx