From patchwork Thu May 6 18:10:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 43275 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 835F23AAB43D; Thu, 6 May 2021 18:10:10 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 835F23AAB43D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1620324610; bh=lSNgp4hWKiEmHiO3+24DhPj69j2skP8zC/IYCe7xwbc=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=KtL7BLMly2gO2jPX/uegdADAeRscrCslxNXB6p9gvrQggx+mh1OyeZK5lX09HE+Y8 ek1Le0JefSusB2xx9tEJksJzCPny7BtDkQxnpZ2wBPY6/r+po2qG/8Xk8DecZR0Cs0 kACrGJ6bTB3Lpy+scFbfK+kSV+wwSr09uYDDDMrk= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 11D603AAB480 for ; Thu, 6 May 2021 18:10:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 11D603AAB480 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-575-_euWyUo2NJGgoJY1M_eNRA-1; Thu, 06 May 2021 14:10:05 -0400 X-MC-Unique: _euWyUo2NJGgoJY1M_eNRA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 13007106BAB7 for ; Thu, 6 May 2021 18:10:04 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-137.ams2.redhat.com [10.36.112.137]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5D98984FCC for ; Thu, 6 May 2021 18:10:03 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH 05/13] Linux: Simplify and fix the definition of SINGLE_THREAD_P In-Reply-To: References: Message-Id: Date: Thu, 06 May 2021 20:10:22 +0200 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Always use __libc_multiple_threads if beneficial, and do not assume the the dynamic loader is single-threaded. This assumption could become incorrect by accident once more code is moved from libpthread into it. The previous commit introducing the NO_SYSCALL_CANCEL_CHECKING macro enables this change. Do not hint to the compiler that multi-threaded programs are unlikely (which is not quite true anymore). Tested-by: Carlos O'Donell Reviewed-by: Carlos O'Donell --- sysdeps/unix/sysv/linux/single-thread.h | 36 +++++-------------------- 1 file changed, 7 insertions(+), 29 deletions(-) diff --git a/sysdeps/unix/sysv/linux/single-thread.h b/sysdeps/unix/sysv/linux/single-thread.h index 841f8c69d5..2fac8dcc11 100644 --- a/sysdeps/unix/sysv/linux/single-thread.h +++ b/sysdeps/unix/sysv/linux/single-thread.h @@ -32,35 +32,13 @@ extern int __libc_multiple_threads; libc_hidden_proto (__libc_multiple_threads) #endif -#ifdef SINGLE_THREAD_BY_GLOBAL -# if IS_IN (libc) -# define SINGLE_THREAD_P \ - __glibc_likely (__libc_multiple_threads == 0) -# elif IS_IN (libpthread) -extern int __pthread_multiple_threads; -# define SINGLE_THREAD_P \ - __glibc_likely (__pthread_multiple_threads == 0) -# elif IS_IN (librt) -# define SINGLE_THREAD_P \ - __glibc_likely (THREAD_GETMEM (THREAD_SELF, \ - header.multiple_threads) == 0) -# else -/* For rtld, et cetera. */ -# define SINGLE_THREAD_P (1) -# endif -#else /* SINGLE_THREAD_BY_GLOBAL */ -# if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt) -# define SINGLE_THREAD_P \ - __glibc_likely (THREAD_GETMEM (THREAD_SELF, \ - header.multiple_threads) == 0) -# else -/* For rtld, et cetera. */ -# define SINGLE_THREAD_P (1) -# endif -#endif /* SINGLE_THREAD_BY_GLOBAL */ +#if !defined SINGLE_THREAD_BY_GLOBAL || IS_IN (rtld) +# define SINGLE_THREAD_P \ + (THREAD_GETMEM (THREAD_SELF, header.multiple_threads) == 0) +#else +# define SINGLE_THREAD_P (__libc_multiple_threads == 0) +#endif -#define RTLD_SINGLE_THREAD_P \ - __glibc_likely (THREAD_GETMEM (THREAD_SELF, \ - header.multiple_threads) == 0) +#define RTLD_SINGLE_THREAD_P SINGLE_THREAD_P #endif /* _SINGLE_THREAD_H */