From owner-freebsd-hackers@FreeBSD.ORG Tue Dec 7 18:02:39 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 90AD31065670; Tue, 7 Dec 2010 18:02:39 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-gw0-f49.google.com (mail-gw0-f49.google.com [74.125.83.49]) by mx1.freebsd.org (Postfix) with ESMTP id 2EBF18FC15; Tue, 7 Dec 2010 18:02:38 +0000 (UTC) Received: by gwj20 with SMTP id 20so183104gwj.36 for ; Tue, 07 Dec 2010 10:02:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=CRvAgQjaZ0RvhXtsniNAlGZe4HRsERFykfTIKSS5XQQ=; b=b5CHC2z6dhlza6DyJmUWOIwiSCRkO9lkl8odaBJCeX/jJANWCoRVGtfPpKE+Evn/Dd /oMkjzMx6Uz0FxHT2kdABIpG539rw/QKxsjHxv9OLvZ5AH9pFzLS4ivd9KS8fm45QPCf fEUYcIVfWkqPQ0pM9Qyn1YlLWSS610ldFrhMU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=ZXPOtFjedztwDxpI+QP62FEeuH26tq7KinuBuvfrJPOxtitMXg2IbHh6MiPjVhaUM3 hPsaoRwTPpiSDYkEAViBBz4nutBvhHa4ea1t66DD34aEy+HdQ7QJE63vAsMI48j9RICT mpyjfBo4RAqJlY/okt9MZEkgMR23UPha+d0aA= MIME-Version: 1.0 Received: by 10.150.11.5 with SMTP id 5mr2224873ybk.430.1291744958360; Tue, 07 Dec 2010 10:02:38 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.236.109.45 with HTTP; Tue, 7 Dec 2010 10:02:38 -0800 (PST) In-Reply-To: <4CFE75D3.4050009@freebsd.org> References: <4CFE75D3.4050009@freebsd.org> Date: Tue, 7 Dec 2010 19:02:38 +0100 X-Google-Sender-Auth: 7VGc5oKXHh8OAA17iV6XO5eQFR8 Message-ID: From: Attilio Rao To: Andriy Gapon Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: freebsd-hackers@freebsd.org Subject: Re: atomic_set_xxx(&x, 0) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Dec 2010 18:02:39 -0000 2010/12/7 Andriy Gapon : > > $ glimpse atomic_set_ | fgrep -w 0 > /usr/src/sys/dev/arcmsr/arcmsr.c: =C2=A0 =C2=A0 =C2=A0 atomic_set_int(&ac= b->srboutstandingcount, 0); > /usr/src/sys/dev/arcmsr/arcmsr.c: =C2=A0 =C2=A0 =C2=A0 atomic_set_int(&ac= b->srboutstandingcount, 0); > /usr/src/sys/dev/jme/if_jme.c: =C2=A0atomic_set_int(&sc->jme_morework, 0)= ; > /usr/src/sys/dev/jme/if_jme.c: =C2=A0atomic_set_int(&sc->jme_morework, 0)= ; > /usr/src/sys/dev/ale/if_ale.c: =C2=A0atomic_set_int(&sc->ale_morework, 0)= ; > /usr/src/sys/mips/rmi/dev/xlr/rge.c: > atomic_set_int(&(priv->frin_to_be_sent[i]), 0); > /usr/src/sys/dev/drm/drm_irq.c: > atomic_set_rel_32(&dev->vblank[i].count, 0); > /usr/src/sys/dev/cxgb/ulp/tom/cxgb_tom.c: =C2=A0 =C2=A0 =C2=A0 atomic_set= _int(&t->tids_in_use, 0); > > I wonder if these are all bugs and atomic_store_xxx() was actually intend= ed? Besides, we assume store on the int boundary is implicitly atomic on all architectures on FreeBSD then, unless a memory barriers is needed, there is no need to use atomic_* in "store" cases. Attilio --=20 Peace can only be achieved by understanding - A. Einstein