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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58FC2C369AB for ; Mon, 21 Apr 2025 05:13:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 042D06B0006; Mon, 21 Apr 2025 01:13:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F334A6B0007; Mon, 21 Apr 2025 01:13:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DFBC16B0008; Mon, 21 Apr 2025 01:13:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id C173E6B0006 for ; Mon, 21 Apr 2025 01:13:12 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BD5225FB30 for ; Mon, 21 Apr 2025 05:13:13 +0000 (UTC) X-FDA: 83356882266.17.1812743 Received: from out-177.mta1.migadu.com (out-177.mta1.migadu.com [95.215.58.177]) by imf20.hostedemail.com (Postfix) with ESMTP id DE0501C0002 for ; Mon, 21 Apr 2025 05:13:11 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=fhM1GVzx; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf20.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.177 as permitted sender) smtp.mailfrom=lance.yang@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1745212392; a=rsa-sha256; cv=none; b=UotnPFI5vw3NlgpugjCDqIuJuyLweSkIx7uuQ7wIzg2GIFpORTbib3Skpxs7b9Y7k75T4j bCWZrBRWv9nXC5S2q98E5RvCbTqBSV9hVUCQ9yULhGhc5cFHEKhnE34W7xORMoXVX6tY+K /Q3FaPBP6eYb/Cy2THeLCUCa/Ol7/dQ= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=fhM1GVzx; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf20.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.177 as permitted sender) smtp.mailfrom=lance.yang@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745212392; h=from:from:sender: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:dkim-signature; bh=Yba2DH1EDjNgUXaKKw6VxTi22gaO7PDpRoTTNn5NzZY=; b=IGWIzur45ORWMp00uotkmwsxB97cPY/QVMJKVlFl4W4X9JR/Ylfx3wz7nnkDvBwT02cv8Z aDRbDCcT5Rt1anmUEhGInWZZVE2w5lk6GkErZCWu5W/9ZRufpj9ZRTtSSYFwOuxZwOT/Eq hwVUB2sZXb219EvY9RuDMaYjmsS3tnI= MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745212388; 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=Yba2DH1EDjNgUXaKKw6VxTi22gaO7PDpRoTTNn5NzZY=; b=fhM1GVzxQjaB8x1SFxwmzboWOamHOE0Rbn8NO4APvL2/MHiixtTPE1IzY3nnSwa+Q7nO3Z 9H06+n43qByybukVepL4b6c/TlJ/nICrronhpL1Hgnkb7zEIxD0DqKzkgksR+HM15NQ6Pp QlpKjOt1nIkSgR9xomwKuyCFg13yhZc= Date: Mon, 21 Apr 2025 05:13:03 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Lance Yang" Message-ID: <641755b75b4ecb9c9822e15e707a0ebf1e250788@linux.dev> TLS-Required: No Subject: Re: [RESEND PATCH v2 1/1] mm/rmap: add CONFIG_MM_ID guard for folio_test_large_maybe_mapped_shared() To: "Andrew Morton" , "David Hildenbrand" Cc: mingzhe.yang@ly.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Lance Yang" In-Reply-To: <20250420162925.2c58c018defee9ee192be553@linux-foundation.org> References: <20250418152228.20545-1-lance.yang@linux.dev> <20250420162925.2c58c018defee9ee192be553@linux-foundation.org> X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: DE0501C0002 X-Stat-Signature: thdkshpxr3fnhopzkxtncgab3irfgw74 X-Rspam-User: X-HE-Tag: 1745212391-346544 X-HE-Meta: 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 LEQW7EsX 2z7zgLqMCWtvdxaAaVluiNjS+ZzlbrokHrNL/ZdiqjvBacHfRpQzSii8YYUj3Ajb/3gdY/SBd7MJaMgEizj3fCyb0vSOv2N/aFEI3pX8KDkVi7/E+2vmw+fnE1+fV2fKsSYGlPsEzrn5iLEWXY+4KBZRNFPUEc3yLJOnNScomcYOYoKdpNLRq5t3tbFxTYHksrK9xOPkEIT35LD5OQtyErPVOzqwfpr+9LgvhixKhbEcOekjy2NDreiyQNSe7WsRL34DALnZ5RfovY1Hht9RM19V2HWd9y1cLfJvjys9Xbn/miGwBySbzNy3UhA== 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: List-Subscribe: List-Unsubscribe: April 21, 2025 at 7:29 AM, "Andrew Morton" wr= ote: >=20 >=20On Fri, 18 Apr 2025 23:22:28 +0800 Lance Yang w= rote: >=20 >=20>=20 >=20> From: Lance Yang > >=20 >=20>=20=20 >=20>=20 >=20> To prevent folio_test_large_maybe_mapped_shared() from being used = without > >=20 >=20> CONFIG_MM_ID, we add a compile-time check rather than wrapping it = in > >=20 >=20> '#ifdef', avoiding even more #ifdef in callers that already use > >=20 >=20> IS_ENABLED(CONFIG_MM_ID). > >=20 >=20>=20=20 >=20>=20 >=20> Also, we used plenty of IS_ENABLED() on purpose to keep the code f= ree of > >=20 >=20> '#ifdef' mess. > >=20 >=20 > I dunno, this just seems really whacky. I'd hope David could leave some comments on that. >=20 >=20>=20 >=20> --- a/include/linux/page-flags.h > >=20 >=20> +++ b/include/linux/page-flags.h > >=20 >=20> @@ -1232,6 +1232,8 @@ static inline int folio_has_private(const st= ruct folio *folio) > >=20 >=20>=20=20 >=20>=20 >=20> static inline bool folio_test_large_maybe_mapped_shared(const stru= ct folio *folio) > >=20 >=20> { > >=20 >=20> + /* This function should never be called without CONFIG_MM_ID ena= bled. */ > >=20 >=20 > A correcter comment would be "This function should never be compiled >=20 >=20without CONFIG_MM_ID enabled". Yes, that is more exact ;) >=20 >=20Which lets the cat out of the bag. Why the heck is it being compiled >=20 >=20with CONFIG_MM_ID=3Dn?? We have tools to prevent that. >=20 >=20Can we just slap "#ifdef CONFIG_MM_ID" around the whole function? It >=20 >=20should have no callers, right? If the linker ends up complaining then >=20 >=20something went wrong. The reason we can't simply add #ifdef CONFIG_MM_ID around folio_test_larg= e_maybe_mapped_shared() is because its caller folio_maybe_mapped_shared() relies on IS_ENABLED(CO= NFIG_MM_ID). If we do, with CONFIG_TRANSPARENT_HUGEPAGE=3DN, we'll hit compilation err= ors like: ./include/linux/mm.h: In function =E2=80=98folio_maybe_mapped_shared=E2= =80=99: ./include/linux/mm.h:2337:16: error: implicit declaration of function =E2= =80=98folio_test_large_maybe_mapped_shared=E2=80=99; did you mean =E2=80= =98folio_maybe_mapped_shared=E2=80=99? [-Werror=3Dimplicit-function-decla= ration] 2337 | return folio_test_large_maybe_mapped_shared(folio); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | folio_maybe_mapped_shared cc1: some warnings being treated as errors Thanks, Lance >