From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C7C7B28E02; Mon, 16 Oct 2023 14:44:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pbL0JENl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65C62C433C7; Mon, 16 Oct 2023 14:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697467467; bh=EosIPRQRkZS/m8fRSYLf1GF9E5dQpYw/H0GO2FrhMzU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=pbL0JENlz5RnGYP4I9kBXyy7y5PAbYeNgIvdEtdEfV+6JtSnYAgZxXfj6QS0OTvnq 7EQLcIfg5sdun4AKj6ILT0f9Sn+Lj6uvsAiodPVGiYDgFZBItlIo32ZAZ94e+7xhcC EzgeCAxFRNF1lIZMxpTdwOblh/UZLmbq4cioT65oxIZDzZFXQX7uvm9EQBD1jalFt1 7JjsKBkOkgur951+Esn3xom0VBOBX9uF/8bVz6kjKcDLzBtDl8aS9RlYKjQ/3DdqNd U2gH58YxGzyynaLl9ZTOovVYCLIQjHNnnlfnqltpw7WhZQlr1WcoivXsWgUIsn7mNI RHCnJAlJeYfQA== Message-ID: Subject: Re: [RFC PATCH 01/53] netfs: Add a procfile to list in-progress requests From: Jeff Layton To: David Howells , Steve French Cc: Matthew Wilcox , Marc Dionne , Paulo Alcantara , Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Dominique Martinet , Ilya Dryomov , Christian Brauner , linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cachefs@redhat.com Date: Mon, 16 Oct 2023 10:44:24 -0400 In-Reply-To: <20231013155727.2217781-2-dhowells@redhat.com> References: <20231013155727.2217781-1-dhowells@redhat.com> <20231013155727.2217781-2-dhowells@redhat.com> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2023-10-13 at 16:56 +0100, David Howells wrote: > Add a procfile, /proc/fs/netfs/requests, to list in-progress netfslib I/O > requests. >=20 > Signed-off-by: David Howells > cc: Jeff Layton > cc: linux-cachefs@redhat.com > cc: linux-fsdevel@vger.kernel.org > cc: linux-mm@kvack.org > --- > fs/netfs/internal.h | 22 +++++++++++ > fs/netfs/main.c | 91 +++++++++++++++++++++++++++++++++++++++++++ > fs/netfs/objects.c | 4 +- > include/linux/netfs.h | 6 ++- > 4 files changed, 121 insertions(+), 2 deletions(-) >=20 > diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h > index 43fac1b14e40..1f067aa96c50 100644 > --- a/fs/netfs/internal.h > +++ b/fs/netfs/internal.h > @@ -29,6 +29,28 @@ int netfs_begin_read(struct netfs_io_request *rreq, bo= ol sync); > * main.c > */ > extern unsigned int netfs_debug; > +extern struct list_head netfs_io_requests; > +extern spinlock_t netfs_proc_lock; > + > +#ifdef CONFIG_PROC_FS > +static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq) > +{ > + spin_lock(&netfs_proc_lock); > + list_add_tail_rcu(&rreq->proc_link, &netfs_io_requests); > + spin_unlock(&netfs_proc_lock); > +} > +static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq) > +{ > + if (!list_empty(&rreq->proc_link)) { > + spin_lock(&netfs_proc_lock); > + list_del_rcu(&rreq->proc_link); > + spin_unlock(&netfs_proc_lock); > + } > +} > +#else > +static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq) {} > +static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq) {} > +#endif > =20 > /* > * objects.c > diff --git a/fs/netfs/main.c b/fs/netfs/main.c > index 068568702957..21f814eee6af 100644 > --- a/fs/netfs/main.c > +++ b/fs/netfs/main.c > @@ -7,6 +7,8 @@ > =20 > #include > #include > +#include > +#include > #include "internal.h" > #define CREATE_TRACE_POINTS > #include > @@ -18,3 +20,92 @@ MODULE_LICENSE("GPL"); > unsigned netfs_debug; > module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO); > MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask"); > + > +#ifdef CONFIG_PROC_FS > +LIST_HEAD(netfs_io_requests); > +DEFINE_SPINLOCK(netfs_proc_lock); > + > +static const char *netfs_origins[] =3D { > + [NETFS_READAHEAD] =3D "RA", > + [NETFS_READPAGE] =3D "RP", > + [NETFS_READ_FOR_WRITE] =3D "RW", > +}; > + > +/* > + * Generate a list of I/O requests in /proc/fs/netfs/requests > + */ > +static int netfs_requests_seq_show(struct seq_file *m, void *v) > +{ > + struct netfs_io_request *rreq; > + > + if (v =3D=3D &netfs_io_requests) { > + seq_puts(m, > + "REQUEST OR REF FL ERR OPS COVERAGE\n" > + "=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D =3D=3D=3D =3D=3D =3D=3D=3D=3D =3D= =3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D\n" > + ); > + return 0; > + } > + > + rreq =3D list_entry(v, struct netfs_io_request, proc_link); > + seq_printf(m, > + "%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx", > + rreq->debug_id, > + netfs_origins[rreq->origin], > + refcount_read(&rreq->ref), > + rreq->flags, > + rreq->error, > + atomic_read(&rreq->nr_outstanding), > + rreq->start, rreq->submitted, rreq->len); > + seq_putc(m, '\n'); > + return 0; > +} > + > +static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos) > + __acquires(rcu) > +{ > + rcu_read_lock(); > + return seq_list_start_head(&netfs_io_requests, *_pos); > +} > + > +static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t= *_pos) > +{ > + return seq_list_next(v, &netfs_io_requests, _pos); > +} > + > +static void netfs_requests_seq_stop(struct seq_file *m, void *v) > + __releases(rcu) > +{ > + rcu_read_unlock(); > +} > + > +static const struct seq_operations netfs_requests_seq_ops =3D { > + .start =3D netfs_requests_seq_start, > + .next =3D netfs_requests_seq_next, > + .stop =3D netfs_requests_seq_stop, > + .show =3D netfs_requests_seq_show, > +}; > +#endif /* CONFIG_PROC_FS */ > + > +static int __init netfs_init(void) > +{ > + if (!proc_mkdir("fs/netfs", NULL)) > + goto error; > + It seems like this should go under debugfs instead. > + if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL, > + &netfs_requests_seq_ops)) > + goto error_proc; > + > + return 0; > + > +error_proc: > + remove_proc_entry("fs/netfs", NULL); > +error: > + return -ENOMEM; > +} > +fs_initcall(netfs_init); > + > +static void __exit netfs_exit(void) > +{ > + remove_proc_entry("fs/netfs", NULL); > +} > +module_exit(netfs_exit); > diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c > index e17cdf53f6a7..85f428fc52e6 100644 > --- a/fs/netfs/objects.c > +++ b/fs/netfs/objects.c > @@ -45,6 +45,7 @@ struct netfs_io_request *netfs_alloc_request(struct add= ress_space *mapping, > } > } > =20 > + netfs_proc_add_rreq(rreq); > netfs_stat(&netfs_n_rh_rreq); > return rreq; > } > @@ -76,12 +77,13 @@ static void netfs_free_request(struct work_struct *wo= rk) > container_of(work, struct netfs_io_request, work); > =20 > trace_netfs_rreq(rreq, netfs_rreq_trace_free); > + netfs_proc_del_rreq(rreq); > netfs_clear_subrequests(rreq, false); > if (rreq->netfs_ops->free_request) > rreq->netfs_ops->free_request(rreq); > if (rreq->cache_resources.ops) > rreq->cache_resources.ops->end_operation(&rreq->cache_resources); > - kfree(rreq); > + kfree_rcu(rreq, rcu); > netfs_stat_d(&netfs_n_rh_rreq); > } > =20 > diff --git a/include/linux/netfs.h b/include/linux/netfs.h > index b11a84f6c32b..b447cb67f599 100644 > --- a/include/linux/netfs.h > +++ b/include/linux/netfs.h > @@ -175,10 +175,14 @@ enum netfs_io_origin { > * operations to a variety of data stores and then stitch the result tog= ether. > */ > struct netfs_io_request { > - struct work_struct work; > + union { > + struct work_struct work; > + struct rcu_head rcu; > + }; > struct inode *inode; /* The file being accessed */ > struct address_space *mapping; /* The mapping being accessed */ > struct netfs_cache_resources cache_resources; > + struct list_head proc_link; /* Link in netfs_iorequests */ > struct list_head subrequests; /* Contributory I/O operations */ > void *netfs_priv; /* Private data for the netfs */ > unsigned int debug_id; >=20 ACK on the general concept however. This is useful debugging info. --=20 Jeff Layton