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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20220316131723.111553-1-jefflexu@linux.alibaba.com> <20220316131723.111553-4-jefflexu@linux.alibaba.com> To: Matthew Wilcox Subject: Re: [PATCH v5 03/22] cachefiles: introduce on-demand read mode MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1029981.1647872043.1@warthog.procyon.org.uk> Date: Mon, 21 Mar 2022 14:14:03 +0000 Message-ID: <1029982.1647872043@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: joseph.qi@linux.alibaba.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-cachefs@redhat.com, gregkh@linuxfoundation.org, luodaowen.backend@bytedance.com, gerry@linux.alibaba.com, linux-erofs@lists.ozlabs.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" Matthew Wilcox wrote: > Why do you have a separate rwlock when the xarray already has its own > spinlock? This is usually a really bad idea. Jeffle wants to hold a lock across the CACHEFILES_DEAD check and the xarray access. However, he tells xarray to do a GFP_KERNEL alloc whilst holding the rwlock:-/ David