Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161094AbWLUAgR (ORCPT ); Wed, 20 Dec 2006 19:36:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161095AbWLUAgQ (ORCPT ); Wed, 20 Dec 2006 19:36:16 -0500 Received: from tomts25-srv.bellnexxia.net ([209.226.175.188]:39849 "EHLO tomts25-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161093AbWLUAgP (ORCPT ); Wed, 20 Dec 2006 19:36:15 -0500 Date: Wed, 20 Dec 2006 19:31:01 -0500 From: Mathieu Desnoyers To: linux-kernel@vger.kernel.org, David Wilder , Tom Zanussi , Andrew Morton , Ingo Molnar , Greg Kroah-Hartman , Christoph Hellwig Cc: ltt-dev@shafik.org, systemtap@sources.redhat.com, Douglas Niehaus , "Martin J. Bligh" , Thomas Gleixner Subject: [PATCH] Relay CPU Hotplug support Message-ID: <20061221003101.GA28643@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.4.32-grsec (i686) X-Uptime: 19:29:46 up 119 days, 21:37, 6 users, load average: 4.21, 3.12, 2.31 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10251 Lines: 391 Hi, Here is a patch, result of the combined work of Tom Zanussi and myself, to add CPU hotplug support to Relay. This patch applies on 2.6.20-rc1-git7. Signed-off-by : Mathieu Desnoyers --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -24,7 +24,7 @@ #define FIX_SIZE(x) ((((x) - 1) & PAGE_M /* * Tracks changes to rchan/rchan_buf structs */ -#define RELAYFS_CHANNEL_VERSION 6 +#define RELAYFS_CHANNEL_VERSION 7 /* * Per-cpu relay channel buffer @@ -64,6 +64,10 @@ struct rchan void *private_data; /* for user-defined data */ size_t last_toobig; /* tried to log event > subbuf size */ struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ + int is_global; /* One global buffer ? */ + struct list_head list; /* for channel list */ + struct dentry *parent; /* parent dentry passed to open */ + char base_filename[NAME_MAX]; /* saved base filename */ }; /* @@ -162,7 +166,8 @@ struct rchan *relay_open(const char *bas struct dentry *parent, size_t subbuf_size, size_t n_subbufs, - struct rchan_callbacks *cb); + struct rchan_callbacks *cb, + void *private_data); extern void relay_close(struct rchan *chan); extern void relay_flush(struct rchan *chan); extern void relay_subbufs_consumed(struct rchan *chan, --- a/kernel/relay.c +++ b/kernel/relay.c @@ -7,6 +7,8 @@ * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com) * * Moved to kernel/relay.c by Paul Mundt, 2006. + * November 2006 - CPU hotplug support by Mathieu Desnoyers + * (mathieu.desnoyers@polymtl.ca) * * This file is released under the GPL. */ @@ -18,6 +20,11 @@ #include #include #include #include +#include + +/* list of open channels, for cpu hotplug */ +static DEFINE_MUTEX(relay_channels_mutex); +static LIST_HEAD(relay_channels); /* * close() vm_op implementation for relay file mapping. @@ -187,6 +194,7 @@ void relay_destroy_buf(struct rchan_buf __free_page(buf->page_array[i]); kfree(buf->page_array); } + chan->buf[buf->cpu] = NULL; kfree(buf->padding); kfree(buf); kref_put(&chan->kref, relay_destroy_channel); @@ -362,58 +370,76 @@ static inline void __relay_reset(struct void relay_reset(struct rchan *chan) { unsigned int i; - struct rchan_buf *prev = NULL; if (!chan) return; - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i] || chan->buf[i] == prev) - break; - __relay_reset(chan->buf[i], 0); - prev = chan->buf[i]; + if (chan->is_global && chan->buf[0]) { + __relay_reset(chan->buf[0], 0); + return; } + + lock_cpu_hotplug(); + for_each_online_cpu(i) + if (chan->buf[i]) + __relay_reset(chan->buf[i], 0); + unlock_cpu_hotplug(); } EXPORT_SYMBOL_GPL(relay_reset); /* * relay_open_buf - create a new relay channel buffer * - * Internal - used by relay_open(). + * used by relay_open() and CPU hotplug. */ -static struct rchan_buf *relay_open_buf(struct rchan *chan, - const char *filename, - struct dentry *parent, - int *is_global) +static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) { - struct rchan_buf *buf; + struct rchan_buf *buf = NULL; struct dentry *dentry; + char *tmpname; - if (*is_global) + if (chan->is_global) return chan->buf[0]; + tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL); + if (!tmpname) + goto end; + snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu); + buf = relay_create_buf(chan); if (!buf) - return NULL; + goto free_name; - /* Create file in fs */ - dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR, - buf, is_global); - if (!dentry) { - relay_destroy_buf(buf); - return NULL; - } + buf->cpu = cpu; + __relay_reset(buf, 1); + /* Create file in fs */ + dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR, + buf, &chan->is_global); + if (!dentry) + goto free_buf; + buf->dentry = dentry; - __relay_reset(buf, 1); + if(chan->is_global) { + chan->buf[0] = buf; + buf->cpu = 0; + } + + goto free_name; + +free_buf: + relay_destroy_buf(buf); +free_name: + kfree(tmpname); +end: return buf; } /** * relay_close_buf - close a channel buffer * @buf: channel buffer - * + * * Marks the buffer finalized and restores the default callbacks. * The channel buffer and channel buffer data structure are then freed * automatically when the last reference is given up. @@ -448,12 +474,54 @@ static inline void setup_callbacks(struc } /** + * + * relay_hotcpu_callback - CPU hotplug callback + * @nb: notifier block + * @action: hotplug action to take + * @hcpu: CPU number + * + * Returns the success/failure of the operation. (NOTIFY_OK, NOTIFY_BAD) + */ +static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb, + unsigned long action, + void *hcpu) +{ + unsigned int hotcpu = (unsigned long)hcpu; + struct rchan *chan; + + switch(action) { + case CPU_UP_PREPARE: + mutex_lock(&relay_channels_mutex); + list_for_each_entry(chan, &relay_channels, list) { + if (chan->buf[hotcpu]) + continue; + chan->buf[hotcpu] = relay_open_buf(chan, hotcpu); + if(!chan->buf[hotcpu]) { + printk(KERN_ERR + "relay_hotcpu_callback: cpu %d buffer " + "creation failed\n", hotcpu); + mutex_unlock(&relay_channels_mutex); + return NOTIFY_BAD; + } + } + mutex_unlock(&relay_channels_mutex); + break; + case CPU_DEAD: + /* No need to flush the cpu : will be flushed upon + * final relay_flush() call. */ + break; + } + return NOTIFY_OK; +} + +/** * relay_open - create a new relay channel * @base_filename: base name of files to create * @parent: dentry of parent directory, %NULL for root directory * @subbuf_size: size of sub-buffers * @n_subbufs: number of sub-buffers * @cb: client callback functions + * @private_data: user-defined data * * Returns channel pointer if successful, %NULL otherwise. * @@ -466,13 +534,11 @@ struct rchan *relay_open(const char *bas struct dentry *parent, size_t subbuf_size, size_t n_subbufs, - struct rchan_callbacks *cb) + struct rchan_callbacks *cb, + void *private_data) { unsigned int i; struct rchan *chan; - char *tmpname; - int is_global = 0; - if (!base_filename) return NULL; @@ -487,38 +553,34 @@ struct rchan *relay_open(const char *bas chan->n_subbufs = n_subbufs; chan->subbuf_size = subbuf_size; chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs); + chan->parent = parent; + chan->private_data = private_data; + strlcpy(chan->base_filename, base_filename, NAME_MAX); setup_callbacks(chan, cb); kref_init(&chan->kref); - tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL); - if (!tmpname) - goto free_chan; - + lock_cpu_hotplug(); for_each_online_cpu(i) { - sprintf(tmpname, "%s%d", base_filename, i); - chan->buf[i] = relay_open_buf(chan, tmpname, parent, - &is_global); + chan->buf[i] = relay_open_buf(chan, i); if (!chan->buf[i]) goto free_bufs; - - chan->buf[i]->cpu = i; } + mutex_lock(&relay_channels_mutex); + list_add(&chan->list, &relay_channels); + mutex_unlock(&relay_channels_mutex); + unlock_cpu_hotplug(); - kfree(tmpname); return chan; free_bufs: - for (i = 0; i < NR_CPUS; i++) { + for_each_online_cpu(i) { if (!chan->buf[i]) break; relay_close_buf(chan->buf[i]); - if (is_global) - break; } - kfree(tmpname); -free_chan: kref_put(&chan->kref, relay_destroy_channel); + unlock_cpu_hotplug(); return NULL; } EXPORT_SYMBOL_GPL(relay_open); @@ -619,24 +681,28 @@ EXPORT_SYMBOL_GPL(relay_subbufs_consumed void relay_close(struct rchan *chan) { unsigned int i; - struct rchan_buf *prev = NULL; if (!chan) return; - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i] || chan->buf[i] == prev) - break; - relay_close_buf(chan->buf[i]); - prev = chan->buf[i]; - } + lock_cpu_hotplug(); + if (chan->is_global && chan->buf[0]) + relay_close_buf(chan->buf[0]); + else + for_each_possible_cpu(i) + if (chan->buf[i]) + relay_close_buf(chan->buf[i]); if (chan->last_toobig) printk(KERN_WARNING "relay: one or more items not logged " "[item size (%Zd) > sub-buffer size (%Zd)]\n", chan->last_toobig, chan->subbuf_size); + mutex_lock(&relay_channels_mutex); + list_del(&chan->list); + mutex_unlock(&relay_channels_mutex); kref_put(&chan->kref, relay_destroy_channel); + unlock_cpu_hotplug(); } EXPORT_SYMBOL_GPL(relay_close); @@ -649,17 +715,20 @@ EXPORT_SYMBOL_GPL(relay_close); void relay_flush(struct rchan *chan) { unsigned int i; - struct rchan_buf *prev = NULL; if (!chan) return; - for (i = 0; i < NR_CPUS; i++) { - if (!chan->buf[i] || chan->buf[i] == prev) - break; - relay_switch_subbuf(chan->buf[i], 0); - prev = chan->buf[i]; + if (chan->is_global && chan->buf[0]) { + relay_switch_subbuf(chan->buf[0], 0); + return; } + + lock_cpu_hotplug(); + for_each_possible_cpu(i) + if (chan->buf[i]) + relay_switch_subbuf(chan->buf[i], 0); + unlock_cpu_hotplug(); } EXPORT_SYMBOL_GPL(relay_flush); @@ -1023,3 +1092,12 @@ const struct file_operations relay_file_ .sendfile = relay_file_sendfile, }; EXPORT_SYMBOL_GPL(relay_file_operations); + +static __init int relay_init(void) +{ + + hotcpu_notifier(relay_hotcpu_callback, 0); + return 0; +} + +module_init(relay_init); --- a/block/blktrace.c +++ b/block/blktrace.c @@ -363,10 +363,9 @@ static int blk_trace_setup(request_queue if (!bt->dropped_file) goto err; - bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks); + bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks, bt); if (!bt->rchan) goto err; - bt->rchan->private_data = bt; bt->act_mask = buts.act_mask; if (!bt->act_mask) OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/