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 2DDF4C433EF for ; Thu, 21 Apr 2022 14:55:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1389749AbiDUO6D (ORCPT ); Thu, 21 Apr 2022 10:58:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1389882AbiDUO56 (ORCPT ); Thu, 21 Apr 2022 10:57:58 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C8126DF12 for ; Thu, 21 Apr 2022 07:55:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650552907; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=vj6OCO47ZlrRD+U4hWtItCGMCXgjWzlITS9H8tfc1CE=; b=JTMz2yOjeqr+DTgfwncEexoOjLTd6E3VqihJagqDRcpieFPpjsdbymsTjl4b6+CtlN+rtw 1Y78H8t+v3o28O43YFwHgVE1Pqznwvsvodno3zH/pYrg+ks3acKJ5Ok81LUVm58muq21GU f5X0hOcNAu6u1/0tmIJhTbA/6lSRoEc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-217-tioexNkoP-2eZL2RIJzJtg-1; Thu, 21 Apr 2022 10:55:02 -0400 X-MC-Unique: tioexNkoP-2eZL2RIJzJtg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A324A185A79C; Thu, 21 Apr 2022 14:55:01 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.13]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2F85940D016E; Thu, 21 Apr 2022 14:54:59 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20220415123614.54024-3-jefflexu@linux.alibaba.com> References: <20220415123614.54024-3-jefflexu@linux.alibaba.com> <20220415123614.54024-1-jefflexu@linux.alibaba.com> To: Jeffle Xu Cc: dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, willy@infradead.org, linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org, luodaowen.backend@bytedance.com, tianzichen@kuaishou.com, fannaihao@baidu.com, zhangjiachen.jaycee@bytedance.com Subject: EMFILE/ENFILE mitigation needed in erofs? MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1447542.1650552898.1@warthog.procyon.org.uk> Date: Thu, 21 Apr 2022 15:54:58 +0100 Message-ID: <1447543.1650552898@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jeffle Xu wrote: > + fd_install(fd, file); Do you need to mitigate potential EMFILE/ENFILE problems? You're potentially trebling up the number of accounted systemwide fds: one for erofs itself, one anonfd per cache object file to communicate with the daemon and one in the daemon to talk to the server. Cachefiles has a fourth internally, but it's kept off the books - further, cachefiles closes them fairly quickly after a period of nonuse. David