From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 9B20A385842B for ; Wed, 27 Apr 2022 13:30:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 9B20A385842B Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-78-oZd_m2FpPr-JSE2WUBElVw-1; Wed, 27 Apr 2022 09:30:25 -0400 X-MC-Unique: oZd_m2FpPr-JSE2WUBElVw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DC2851C0854E; Wed, 27 Apr 2022 13:30:24 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 16536404D2EE; Wed, 27 Apr 2022 13:30:23 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella via Libc-alpha Subject: Re: [PATCH v2 3/4] Move libio lock single-thread optimization to generic libc-lock (BZ #27842) References: <20220426191523.833171-1-adhemerval.zanella@linaro.org> <20220426191523.833171-4-adhemerval.zanella@linaro.org> Date: Wed, 27 Apr 2022 15:30:22 +0200 In-Reply-To: <20220426191523.833171-4-adhemerval.zanella@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Tue, 26 Apr 2022 16:15:22 -0300") Message-ID: <87k0bahcwh.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-11.7 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, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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-List-Received-Date: Wed, 27 Apr 2022 13:30:33 -0000 * Adhemerval Zanella via Libc-alpha: > diff --git a/sysdeps/nptl/libc-lock.h b/sysdeps/nptl/libc-lock.h > index 6c2d6acfd1..abd84e71b4 100644 > --- a/sysdeps/nptl/libc-lock.h > +++ b/sysdeps/nptl/libc-lock.h > @@ -86,7 +86,7 @@ typedef struct { int lock; int cnt; void *owner; } __libc_lock_recursive_t; > # define __libc_lock_lock_recursive(NAME) \ > do { \ > void *self = THREAD_SELF; \ > - if ((NAME).owner != self) \ > + if (!SINGLE_THREAD_P && (NAME).owner != self) \ > { \ > lll_lock ((NAME).lock, LLL_PRIVATE); \ > (NAME).owner = self; \ > @@ -104,7 +104,7 @@ typedef struct { int lock; int cnt; void *owner; } __libc_lock_recursive_t; > ({ \ > int result = 0; \ > void *self = THREAD_SELF; \ > - if ((NAME).owner != self) \ > + if (!SINGLE_THREAD_P && (NAME).owner != self) \ > { \ > if (lll_trylock ((NAME).lock) == 0) \ > { \ > @@ -131,7 +131,8 @@ typedef struct { int lock; int cnt; void *owner; } __libc_lock_recursive_t; > if (--(NAME).cnt == 0) \ > { \ > (NAME).owner = NULL; \ > - lll_unlock ((NAME).lock, LLL_PRIVATE); \ > + if (!SINGLE_THREAD_P) \ > + lll_unlock ((NAME).lock, LLL_PRIVATE); \ > } \ > } while (0) > #else I don't think this is correct if threads are created in the lock region. Thanks, Florian