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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F3FDC6FD18 for ; Wed, 29 Mar 2023 07:52:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230253AbjC2Hwg (ORCPT ); Wed, 29 Mar 2023 03:52:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230247AbjC2HwA (ORCPT ); Wed, 29 Mar 2023 03:52:00 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26A1B46B5; Wed, 29 Mar 2023 00:51:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+xoloHvgkvnUwe+7/mW4SGlzimEaFuLJW1cg0sgwA58=; b=DjYX9YfvtOFYsLi2tr8jvgeYc0 xWYqoPI1MrDacRMh6Pm4KaJs2gHpJ/wy4G02uqxMSMs/CM5G6r3RQaAf4WPjK9/caYmZpBr7RzcV+ MomD4y0ZyP43q6qy80wes0rvLXilUmDaVZhqwQRqySsyN8YD0PFcrWu1iG/iOuROX9VXWJ2zPMRyC rsceboL9zWFzjT9+nUOhskUitKzIPA3SlreHvnwsocTUmWMTexgmVVzKRwl0kEB+2VYz5PJbaJSxJ cL/lMy5nWX+e14Xv2PvoNDBb9j4Ikclt485t/MeuwMZsSi79eRpIb+IU27fSPe/Pr4eRzeyB8/FGH xIQrC0sA==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1phQay-00Gy5R-32; Wed, 29 Mar 2023 07:51:48 +0000 Date: Wed, 29 Mar 2023 00:51:48 -0700 From: Luis Chamberlain To: Peter Zijlstra Cc: david@redhat.com, patches@lists.linux.dev, linux-modules@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, pmladek@suse.com, petr.pavlu@suse.com, prarit@redhat.com, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, rafael@kernel.org, christophe.leroy@csgroup.eu, tglx@linutronix.de, song@kernel.org, rppt@kernel.org, willy@infradead.org, vbabka@suse.cz, mhocko@suse.com, dave.hansen@linux.intel.com Subject: Re: [PATCH 4/7] sempahore: add a helper for a concurrency limiter Message-ID: References: <20230329053149.3976378-1-mcgrof@kernel.org> <20230329053149.3976378-5-mcgrof@kernel.org> <20230329072112.GG4253@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230329072112.GG4253@hirez.programming.kicks-ass.net> Sender: Luis Chamberlain Precedence: bulk List-ID: On Wed, Mar 29, 2023 at 09:21:12AM +0200, Peter Zijlstra wrote: > On Tue, Mar 28, 2023 at 10:31:46PM -0700, Luis Chamberlain wrote: > > While I looked at re-using the old kernel/kmod.c (now kernel/module/kmod.c) > > concurrency delimiter methodology for another place in the kernel Linus > > noted that this could be simply replaced with a sempahore [0]. > > > > So add that so we we don't re-invent the wheel and make it obvious to use. > > > > [0] https://lore.kernel.org/all/CAHk-=whkj6=wyi201JXkw9iT_eTUTsSx+Yb9d4OgmZFjDJA18g@mail.gmail.com/ > > > > Suggested-by: Linus Torvalds > > Signed-off-by: Luis Chamberlain > > --- > > include/linux/semaphore.h | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h > > index 6694d0019a68..2ecdffdb9814 100644 > > --- a/include/linux/semaphore.h > > +++ b/include/linux/semaphore.h > > @@ -28,6 +28,9 @@ struct semaphore { > > #define DEFINE_SEMAPHORE(name) \ > > struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) > > > > +#define CONCURRENCY_LIMITER(name, n) \ > > + struct semaphore name = __SEMAPHORE_INITIALIZER(name, n) > > + > > Why should this live in semaphore.h? I have no preference, but sharing seems to have been better. Do you have any recommendations? Luis