From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (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 1D1441AA1F4 for ; Wed, 1 Jul 2026 06:49:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782888596; cv=none; b=tfy3VKfsK4Q/Sdax1Fx3cvXfHxa6216Flpmb0JLA1b/jMxcNTc4FsBsehLn0orPWxRi46hBp+CqA5ldgzZDbp5ArYvrHG8cELHVtnlplhZwcmDqLg1r6pHl/TmWPoHu8qgFpQS2Pvyx7140j+47PM84KZ7XQZr9Vc5U3H+aQ3L8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782888596; c=relaxed/simple; bh=zd2opAEZdyfY+D+0IbQCuD9WR9PIvtSdIduSxlL8mTg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=Va4kAfKaaBVf/CImn/4my82mp6ta4ArTgh8ST0QYPO5GOP/H8erhzMN5v8nEx1zg3hMrvdO0O2Gjt3mnjxBIzWwJ16u83VnPKMmgwpO+hya/CLL29bdk3kZoxCgCrVpIBsxwDxkySqujx26Dx5UbGMSvr/AuUHCppuI0Q9gFe6Y= 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=ZROQTcya; arc=none smtp.client-ip=91.218.175.185 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="ZROQTcya" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1782888591; 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=zd2opAEZdyfY+D+0IbQCuD9WR9PIvtSdIduSxlL8mTg=; b=ZROQTcyaCG+fELLScxaOCHawW/fBPCebAni5xoGNnpS/3Jr2CCPf5rOPz3W5ERDJhOTiby m9DSyqQMsiV1ye850laC9XEqpHhBhkI4UPuCIsIWVD5Wc9yz1oSDERI4vJ7uRtQHMNoCmy eyRXQFirBLuTuDf+NKLcJTd0DbiT460= From: Lance Yang To: ziy@nvidia.com Cc: akpm@linux-foundation.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, david@kernel.org, ljs@kernel.org, baolin.wang@linux.alibaba.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, rppt@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] mm/compaction: stop recording free page order in page->private Date: Wed, 1 Jul 2026 14:49:37 +0800 Message-Id: <20260701064937.5131-1-lance.yang@linux.dev> In-Reply-To: <20260628-keep-subpage-private-zero-at-free-v1-1-f4ce3930d10f@nvidia.com> References: <20260628-keep-subpage-private-zero-at-free-v1-1-f4ce3930d10f@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On Sun, Jun 28, 2026 at 10:56:19PM -0400, Zi Yan wrote: >Commit 733aea0b3a7bb ("mm/compaction: add support for >0 order folio >memory compaction.") stores isolated free pages in an array indexed by free >page orders, it is no longer needed to store the order in each page's >->private field. And there is no code using the stored order. Stop doing >that. > >It also prepares for an upcoming change that ensures subpage->private is >zero at page free time and the removal of set_page_private(0) from >prep_compound_tail(). In alloc_contig_frozen_range_noprof(), >isolate_freepages_range() is used to grab free pages from buddy allocator >and it leaves the aforementioned page->private set until >either split_free_frozen_pages() or prep_new_page() is called. That >triggers the upcoming subpage->private nonzero check along once >set_page_private(0) is removed from prep_compound_tail(), which is called >via prep_new_page(). > >Signed-off-by: Zi Yan >--- IIUC, after isolation, the order is tracked by the per-order freelist :) LGTM, feel free to add: Reviewed-by: Lance Yang