From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2DD43CF3185 for ; Wed, 19 Nov 2025 10:13:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=szA32RJyVbeRYTjJ7Ow9x4Y9um0eAlyuuRKChzXOWH8=; b=zE52Vkz+On21FgUoJifBDICng+ ssuyG14Z58gOZ1nJaqiMUVU2VJg4Pkb4MhnenHAgvOFgyDjgpNxa4u1tQyQhXPn+5dtYgDXDuDSZv DnlmOV8JCWhw3zkkg+H/04b3m1z+xWquW3EXtoqVw60TOSkgXadtcUkzfRnBA51ESw0Jdia3W+YQu zzRplHXWAlvNl538Pw6fF7Igp1SKKx0RJgw21L+fg4BkWF/RnAr7s6kukqy3C8O6KDP7CEkrJcSNq bhMy3v8xf1fsecw0RdEaLSNYy1z2TnirwGsPlZFYC1rTg6L6Pw7fFGwna9U95KKAiHmWtwZASrAAF iJHdoGzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLfCC-00000002wl2-3Ghv; Wed, 19 Nov 2025 10:13:52 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLfCA-00000002wkX-0iuW; Wed, 19 Nov 2025 10:13:51 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 8355C43FA7; Wed, 19 Nov 2025 10:13:46 +0000 (UTC) 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251119_021350_236115_154830E8 X-CRM114-Status: UNSURE ( 8.66 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org 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