From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BBC3E21D3F5; Wed, 19 Nov 2025 10:13:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763547226; cv=none; b=JLs3A9L/QkjTZRrHS8yhXr5hKjIIdU9TPtFR7veSP+4Se186eFcfUaOmVnrooTJgD03AZatdFDz1w+FyTKmyZKJTw80C//N6Lp3GrRaz1KXdnyyBbKyx9Z1jRPz6Hh3oBMY1XwWw8nm8D1z+Ykw+wuyOdLHiCFzL/dskix8tFno= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763547226; c=relaxed/simple; bh=8IYxu/C3qrGid3n3xMVLRSBITnzao99XRln0ciNWneY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZExnWfRpAZAS8dF07xC1U6sKrJ11GGQPFu6NkAJ+I8gwAjETJY/uWowkDWwd4Sdb4eBwyVywsGe7YI2Ug9ArB7/nufyaplQNxjA7lZ2/Q7txa9wNr6lF3aF5uiKQ3vauRJoq/smzOPeo85HP23HqBKqy2wklcMTtYp6rKJkUzKs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LdGoDxJt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LdGoDxJt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB52CC16AAE; Wed, 19 Nov 2025 10:13:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763547226; bh=8IYxu/C3qrGid3n3xMVLRSBITnzao99XRln0ciNWneY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LdGoDxJt9h1Tlf1FCndkLyh+OwHFWpLYja9EnuhCaStGYdTO/u/3+Fxjm8oCvXk2/ E35KNa8rkDsQ4bPiZhB7BvC+7G9u3vv2O95UQNcf+uUOrfyBdK3uT+eewjqJwxMg6f O1rm2iLUscQJgkXdhNOc9AFc9kCFpZIhNjSzZINyqhCmWVFyFPOvsz8HJeqmQXW4+H s7XMLF+PxrmhzX0byFy0OOO5Djr+zth+JdHGDpKJGZ+dUbNfoMyOEIkvtSt3VTig0u DjN5MNM3mx4xWC+cutnpwm7m5sszHgWntNoXn6IOKKCqq/T/Yv6HJIdQv894sJyfel bVNiG5QRYn7SA== Message-ID: Date: Wed, 19 Nov 2025 11:13:37 +0100 Precedence: bulk X-Mailing-List: linux-parisc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/7] enable PT_RECLAIM on all 64-bit architectures To: Qi Zheng , Qi Zheng , will@kernel.org, aneesh.kumar@kernel.org, npiggin@gmail.com, peterz@infradead.org, dev.jain@arm.com, akpm@linux-foundation.org, ioworker0@gmail.com Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-um@lists.infradead.org, Qi Zheng References: <83e88171-54cb-4112-a344-f6a7d7f13784@kernel.org> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 18.11.25 12:53, Qi Zheng wrote: > > > On 11/18/25 12:53 AM, David Hildenbrand (Red Hat) wrote: >> On 14.11.25 12:11, Qi Zheng wrote: >>> From: Qi Zheng >>> >>> Hi all, >>> >>> This series aims to enable PT_RECLAIM on all 64-bit architectures. >>> >>> On a 64-bit system, madvise(MADV_DONTNEED) may cause a large number of >>> empty PTE >>> page table pages (such as 100GB+). To resolve this problem, we need to >>> enable >>> PT_RECLAIM, which depends on MMU_GATHER_RCU_TABLE_FREE. >>> >> >> Makes sense! >> >>> Therefore, this series first enables MMU_GATHER_RCU_TABLE_FREE on all >>> 64-bit >>> architectures, and finally makes PT_RECLAIM depend on >>> MMU_GATHER_RCU_TABLE_FREE >>> && 64BIT. This way, PT_RECLAIM can be enabled by default on all 64-bit >>> architectures. >> >> Could we then even go ahead and stop making PT_RECLAIM user-selectable? > > OK, will change to: Was more of a question: is there any scenario where we ran so far into issues with it? -- Cheers David