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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 X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RDNS_NONE,SPF_HELO_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net 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