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 X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2785C433FE for ; Mon, 7 Dec 2020 22:53:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4C63D239EB for ; Mon, 7 Dec 2020 22:53:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C63D239EB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9824A8D0002; Mon, 7 Dec 2020 17:53:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 932718D0001; Mon, 7 Dec 2020 17:53:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 847BA8D0002; Mon, 7 Dec 2020 17:53:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0203.hostedemail.com [216.40.44.203]) by kanga.kvack.org (Postfix) with ESMTP id 6BEEF8D0001 for ; Mon, 7 Dec 2020 17:53:54 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 2F1E0180AD807 for ; Mon, 7 Dec 2020 22:53:54 +0000 (UTC) X-FDA: 77567990388.05.vest11_62037f0273e2 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id 0A24F1801815A for ; Mon, 7 Dec 2020 22:53:54 +0000 (UTC) X-HE-Tag: vest11_62037f0273e2 X-Filterd-Recvd-Size: 5436 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Mon, 7 Dec 2020 22:53:53 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 01174AB63; Mon, 7 Dec 2020 22:53:52 +0000 (UTC) Received: by lion.mk-sys.cz (Postfix, from userid 1000) id 82A27603C1; Mon, 7 Dec 2020 23:53:51 +0100 (CET) Date: Mon, 7 Dec 2020 23:53:51 +0100 From: Michal Kubecek To: Alexei Starovoitov Cc: Justin Forbes , bpf , Alex Shi , Andrew Morton , Souptick Joarder , Linux-MM , LKML , Alexei Starovoitov , Daniel Borkmann , Josef Bacik Subject: Re: [PATCH] mm/filemap: add static for function __add_to_page_cache_locked Message-ID: <20201207225351.2liywqaxxtuezzw3@lion.mk-sys.cz> References: <1604661895-5495-1-git-send-email-alex.shi@linux.alibaba.com> <20201110115037.f6a53faec8d65782ab65d8b4@linux-foundation.org> <20201207081556.pwxmhgdxayzbofpi@lion.mk-sys.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable 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: On Mon, Dec 07, 2020 at 02:44:22PM -0800, Alexei Starovoitov wrote: > On Mon, Dec 7, 2020 at 10:36 AM Justin Forbes wr= ote: > > > > On Mon, Dec 7, 2020 at 2:16 AM Michal Kubecek wrot= e: > > > > > > On Thu, Nov 12, 2020 at 08:18:57AM +0800, Alex Shi wrote: > > > > > > > > > > > > =E5=9C=A8 2020/11/11 =E4=B8=8A=E5=8D=883:50, Andrew Morton =E5=86= =99=E9=81=93: > > > > > On Tue, 10 Nov 2020 08:39:24 +0530 Souptick Joarder wrote: > > > > > > > > > >> On Fri, Nov 6, 2020 at 4:55 PM Alex Shi wrote: > > > > >>> > > > > >>> Otherwise it cause gcc warning: > > > > >>> ^~~~~~~~~~~~~~~ > > > > >>> ../mm/filemap.c:830:14: warning: no previous prototype for > > > > >>> =E2=80=98__add_to_page_cache_locked=E2=80=99 [-Wmissing-proto= types] > > > > >>> noinline int __add_to_page_cache_locked(struct page *page, > > > > >>> ^~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > >> > > > > >> Is CONFIG_DEBUG_INFO_BTF enabled in your .config ? > > > > > > > > > > hm, yes. > > > > > > > > When the config enabled, compiling looks good untill pahole tool > > > > used to get BTF info, but I still failed on a right version pahol= e > > > > > 1.16. Sorry. > > > > > > > > > > > > > >>> > > > > >>> Signed-off-by: Alex Shi > > > > >>> Cc: Andrew Morton > > > > >>> Cc: linux-mm@kvack.org > > > > >>> Cc: linux-kernel@vger.kernel.org > > > > >>> --- > > > > >>> mm/filemap.c | 2 +- > > > > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > > > > >>> > > > > >>> diff --git a/mm/filemap.c b/mm/filemap.c > > > > >>> index d90614f501da..249cf489f5df 100644 > > > > >>> --- a/mm/filemap.c > > > > >>> +++ b/mm/filemap.c > > > > >>> @@ -827,7 +827,7 @@ int replace_page_cache_page(struct page *= old, struct page *new, gfp_t gfp_mask) > > > > >>> } > > > > >>> EXPORT_SYMBOL_GPL(replace_page_cache_page); > > > > >>> > > > > >>> -noinline int __add_to_page_cache_locked(struct page *page, > > > > >>> +static noinline int __add_to_page_cache_locked(struct page *= page, > > > > >>> struct address_space = *mapping, > > > > >>> pgoff_t offset, gfp_t= gfp, > > > > >>> void **shadowp) > > > > > > > > > > It's unclear to me whether BTF_ID() requires that the target sy= mbol be > > > > > non-static. It doesn't actually reference the symbol: > > > > > > > > > > #define BTF_ID(prefix, name) \ > > > > > __BTF_ID(__ID(__BTF_ID__##prefix##__##name##__)) > > > > > > > > > > > > > The above usage make me thought BTF don't require the symbol, tho= ugh > > > > the symbol still exist in vmlinux with 'static'. > > > > > > > > So any comments of this, Alexei? >=20 > Sorry. I've completely missed this thread. > Now I have a hard time finding context in archives. > If I understood what's going on the removal of "static" cases issues? > Yes. That's expected. > noinline alone is not enough to work reliably. Not removal, commit 3351b16af494 ("mm/filemap: add static for function __add_to_page_cache_locked") made the function static which breaks the build in btfids phase - but it seems to happen only on some architectures. In our case, ppc64, ppc64le and riscv64 are broken, x86_64, i586 and s390x succeed. (I made a mistake above, aarch64 did not fail - but only because it was not built at all.) The thread starts with http://lkml.kernel.org/r/1604661895-5495-1-git-send-email-alex.shi@linux.= alibaba.com Michal