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Fri, 02 Feb 2024 02:46:21 -0800 (PST) MIME-Version: 1.0 References: <2701318.1706863882@warthog.procyon.org.uk> <2704767.1706869832@warthog.procyon.org.uk> In-Reply-To: <2704767.1706869832@warthog.procyon.org.uk> From: Miklos Szeredi Date: Fri, 2 Feb 2024 11:46:10 +0100 Message-ID: Subject: Re: [LSF/MM/BPF TOPIC] Replacing TASK_(UN)INTERRUPTIBLE with regions of uninterruptibility To: David Howells Cc: lsf-pc@lists.linux-foundation.org, Matthew Wilcox , Kent Overstreet , dwmw2@infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: senwq7h6epfocdm3ci8gmgsup4bptsem X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: EB49620015 X-Rspam-User: X-HE-Tag: 1706870783-301803 X-HE-Meta: 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 HvYfyB3o FL+pWgCLEKWZ3UgN8czhXFVSzw38dApAetAdhLRbnMIbzMvU2UV8gVGn11rW/oBJzZlWtxFdmMh09a9nJ8MpNzQaXpuDsBmgQQzTRnOVET4BBEhKwwwEiX7ISYdslj0B09Fomh0AV02eagnFbCuwxNRZXgxsZ3ydpJiObz+Xqaof+bmax7qH0y4kqUje63/H5+MshSPj9r3YTopYfM7aJwHhH60sxZYSbwJMlkXN7V1iukvAu+z7x1bsOSTebdGoiRJn3InrY/3b/GGH77h2OovSRWnMiyGmUzi4v6SAK1QwCGxI/1C0EgO2hzxuyakKv4lS5BA6qtYBCHMQ= X-Bogosity: Ham, tests=bogofilter, spamicity=0.013517, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 2 Feb 2024 at 11:30, David Howells wrote: > > Miklos Szeredi wrote: > > > > We have various locks, mutexes, etc., that are taken on entry to > > > filesystem code, for example, and a bunch of them are taken interruptibly > > > or killably (or ought to be) - but filesystem code might be called into > > > from uninterruptible code, such as the memory allocator, fscache, etc.. > > > > Are you suggesting to make lots more filesystem/vfs/mm sleeps > > killable? That would present problems with being called from certain > > contexts. > > No, it wouldn't. What I'm suggesting is something like: > > overlayfs_mkdir(inode) > { > inode_lock(inode); <--- This could be interruptible Just making inode_lock() interruptible would break everything. So I assume this is not what you meant, but that we add error handling to each and every inode_lock() call? > ... > begin_task_uninterruptible(); Yes, I understand that this is your suggestion. For overlayfs it doesn't really make sense, but for network fs and fuse I guess it could be interesting. I would have thought that making all fs related sleeping locks interruptible is not something that would be worth the effort, but maybe you have a very good use case. Thanks, Miklos