From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (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 CD4E832C322 for ; Wed, 19 Nov 2025 10:38:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763548691; cv=none; b=jpJFhJlu2Pmj46tLEoZi8uB3quzUg5wkcYJf6T2e6WzULwF8gSGjqzlu43ZT9v2ieh5sre6vyh9G3/UdIdmpIIxJsCMx5C0UE9LhM8Gxz7lwuBTDlzglm7PfSJmydgdI3kp1pd2iZ7T3bdUMz4JdnhZgA7U0KgbJWPQWbdgMY1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763548691; c=relaxed/simple; bh=qsv2yYTKolrKy0b9rHk18vlAbL6i6ada3LOYA8zKeVo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TRX/BtjV/Z7+TVANUCHax28Uy9Q6BNtHCqD6Kqvltb49nNiX0RZxg5CCh4f5pgDrMZmHBiprLMd4haBIQdbVfoC+J37HOTvtGZMRgxRGjeOdHpG6zCr24yuUYUiVBFnImb7J/hLi9+rN/t68DeNU0GQVnnd4DF7uRpNbpU6gWi8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=WlmCPbWn; arc=none smtp.client-ip=91.218.175.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="WlmCPbWn" Message-ID: <9c884aeb-c1ec-4fe0-8495-639344633569@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1763548677; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2TBsWCikXGWQPUUHsPA7sycMNKDe7zouYf7GZ8q6JeI=; b=WlmCPbWnPdAaCcans4XB+sX3p9j7swCRg/bKjIgLcOdwHQGNX8Ly6s46NtS/bk1YRUX5nD P/USmoX3HrHHdMyNu4n5ttfSh4oinQ+knKhggVYN1S4ezwiWm1UMI+WsjcrjIT6sAYxVwY YCuykmmow7b6GErFp6rT+UF5iCgIJi0= Date: Wed, 19 Nov 2025 18:37:47 +0800 Precedence: bulk X-Mailing-List: linux-alpha@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 0/7] enable PT_RECLAIM on all 64-bit architectures To: "David Hildenbrand (Red Hat)" , 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> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 11/19/25 6:13 PM, David Hildenbrand (Red Hat) wrote: > 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? No, I haven't received any reports of related issues, either within the company or in the community. >