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Message-Id: <1222496313.6710.81.camel@charm-linux>
Date: Sat, 27 Sep 2008 01:18:32 -0500
From: Tom Zanussi <zanussi@...cast.net>
To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc: Martin Bligh <mbligh@...gle.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
prasad@...ux.vnet.ibm.com,
Linus Torvalds <torvalds@...ux-foundation.org>,
Thomas Gleixner <tglx@...utronix.de>,
Mathieu Desnoyers <compudj@...stal.dyndns.org>,
Steven Rostedt <rostedt@...dmis.org>, od@...e.com,
"Frank Ch. Eigler" <fche@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>, hch@....de,
David Wilder <dwilder@...ibm.com>
Subject: [RFC PATCH 10/10] relay - Remove sub-buffers from relay.
Remove sub-buffers from relay.
This patch removes the concept of sub-buffers from relay - everything
now just operates on pages. relay_open() was also changed
accordingly; instead of specifying buffer sizes in terms of sub-buffer
sizes and numbers, the buffer size is specfied in pages. There's also
a new param that specifies how often to wake up consumers, in terms of
every n pages produced. If 0 is given for this param, consumers are
never woken up.
---
block/blktrace.c | 7 +-
include/linux/relay.h | 113 +++++++++++-----------
kernel/relay.c | 257
++++++++++++++++++++++++-------------------------
virt/kvm/kvm_trace.c | 25 +++--
4 files changed, 202 insertions(+), 200 deletions(-)
diff --git a/block/blktrace.c b/block/blktrace.c
index c04168b..84a9cb4 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -359,6 +359,7 @@ int do_blk_trace_setup(struct request_queue *q, char
*name, dev_t dev,
struct blk_trace *old_bt, *bt = NULL;
struct dentry *dir = NULL;
int ret, i;
+ int n_pages, n_pages_wakeup;
if (!buts->buf_size || !buts->buf_nr)
return -EINVAL;
@@ -403,8 +404,10 @@ int do_blk_trace_setup(struct request_queue *q,
char *name, dev_t dev,
if (!bt->msg_file)
goto err;
- bt->rchan = relay_open("trace", dir, buts->buf_size,
- buts->buf_nr, &blk_relay_callbacks, bt, 0UL);
+ n_pages = (buts->buf_size * buts->buf_nr) / PAGE_SIZE;
+ n_pages_wakeup = buts->buf_size / PAGE_SIZE;
+ bt->rchan = relay_open("trace", dir, n_pages, n_pages_wakeup,
+ &blk_relay_callbacks, bt, 0UL);
if (!bt->rchan)
goto err;
diff --git a/include/linux/relay.h b/include/linux/relay.h
index dd51caf..e0b1730 100644
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -19,9 +19,6 @@
#include <linux/poll.h>
#include <linux/kref.h>
-/* Needs a _much_ better name... */
-#define FIX_SIZE(x) ((((x) - 1) & PAGE_MASK) + PAGE_SIZE)
-
/*
* Tracks changes to rchan/rchan_buf structs
*/
@@ -39,10 +36,10 @@
struct rchan_buf
{
void *start; /* start of channel buffer */
- void *data; /* start of current sub-buffer */
- size_t offset; /* current offset into sub-buffer */
- size_t subbufs_produced; /* count of sub-buffers produced */
- size_t subbufs_consumed; /* count of sub-buffers consumed */
+ void *data; /* start of current page */
+ size_t offset; /* current offset into page */
+ size_t produced; /* count of pages produced */
+ size_t consumed; /* count of pages consumed */
struct rchan *chan; /* associated channel */
wait_queue_head_t read_wait; /* reader wait queue */
struct timer_list timer; /* reader wake-up timer */
@@ -51,7 +48,7 @@ struct rchan_buf
struct page **page_array; /* array of current buffer pages */
unsigned int page_count; /* number of current buffer pages */
unsigned int finalized; /* buffer has been finalized */
- size_t bytes_consumed; /* bytes consumed in cur read subbuf */
+ size_t consumed_offset; /* bytes consumed in cur page */
size_t early_bytes; /* bytes consumed before VFS inited */
unsigned int cpu; /* this buf's cpu */
} ____cacheline_aligned;
@@ -62,13 +59,13 @@ struct rchan_buf
struct rchan
{
u32 version; /* the version of this struct */
- size_t subbuf_size; /* sub-buffer size */
- size_t n_subbufs; /* number of sub-buffers per buffer */
+ size_t n_pages; /* number of pages per buffer */
+ size_t n_pages_wakeup; /* wake up readers after filling n */
size_t alloc_size; /* total buffer size allocated */
struct rchan_callbacks *cb; /* client callbacks */
struct kref kref; /* channel refcount */
void *private_data; /* for user-defined data */
- size_t last_toobig; /* tried to log event > subbuf size */
+ size_t last_toobig; /* tried to log event > page size */
struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
struct list_head list; /* for channel list */
struct dentry *parent; /* parent dentry passed to open */
@@ -84,25 +81,24 @@ struct rchan
struct rchan_callbacks
{
/*
- * new_subbuf - called on buffer-switch to a new sub-buffer
- * @buf: the channel buffer containing the new sub-buffer
- * @subbuf: the start of the new sub-buffer
+ * new_page - called on switch to a new page
+ * @buf: the channel buffer containing the new page
+ * @page_data: the start of the new page
*
- * This is simply a notification that a new sub-buffer has
- * been started. The default version does nothing but call
+ * This is simply a notification that a new page has been
+ * switched to. The default version does nothing but call
* relay_wakeup_readers(). Clients who override this callback
* should also call relay_wakeup_readers() to get that default
* behavior in addition to whatever they add. Clients who
* don't want to wake up readers should just not call it.
* Clients can use the channel private_data to track previous
- * sub-buffers, determine whether this is the first
- * sub-buffer, etc.
+ * pages, determine whether this is the first page, etc.
*
* NOTE: the client can reserve bytes at the beginning of the new
- * sub-buffer by calling subbuf_start_reserve() in this
callback.
+ * page by calling page_start_reserve() in this callback.
*/
- void (*new_subbuf) (struct rchan_buf *buf,
- void *subbuf);
+ void (*new_page) (struct rchan_buf *buf,
+ void *page_data);
/*
* buf_mapped - relay buffer mmap notification
@@ -159,7 +155,7 @@ struct rchan_callbacks
int (*remove_buf_file)(struct dentry *dentry);
/*
- * switch_subbuf - sub-buffer switch callback
+ * switch_page - page switch callback
* @buf: the channel buffer
* @length: size of current event
* @reserved: a pointer to the space reserved
@@ -170,12 +166,12 @@ struct rchan_callbacks
*
* Returns either the length passed in or 0 if full.
*
- * Performs sub-buffer-switch tasks such as updating filesize,
+ * Performs page-switch tasks such as updating filesize,
* waking up readers, etc.
*/
- size_t (*switch_subbuf)(struct rchan_buf *buf,
- size_t length,
- void **reserved);
+ size_t (*switch_page)(struct rchan_buf *buf,
+ size_t length,
+ void **reserved);
};
/*
@@ -184,8 +180,8 @@ struct rchan_callbacks
struct rchan *relay_open(const char *base_filename,
struct dentry *parent,
- size_t subbuf_size,
- size_t n_subbufs,
+ size_t n_pages,
+ size_t n_pages_wakeup,
struct rchan_callbacks *cb,
void *private_data,
unsigned long rchan_flags);
@@ -194,26 +190,33 @@ extern int relay_late_setup_files(struct rchan
*chan,
struct dentry *parent);
extern void relay_close(struct rchan *chan);
extern void relay_flush(struct rchan *chan);
-extern void relay_subbufs_consumed(struct rchan *chan,
- unsigned int cpu,
- size_t consumed);
+extern void relay_pages_consumed(struct rchan *chan,
+ unsigned int cpu,
+ size_t consumed);
extern void relay_reset(struct rchan *chan);
extern int relay_buf_full(struct rchan_buf *buf);
-extern size_t relay_switch_subbuf_default_callback(struct rchan_buf
*buf,
- size_t length,
- void **reserved);
+extern size_t relay_switch_page_default_callback(struct rchan_buf *buf,
+ size_t length,
+ void **reserved);
/**
* relay_wakeup_readers - wake up readers if applicable
* @buf: relay channel buffer
*
- * Called by new_subbuf() default implementation, pulled out for
- * the conveiennce of user-defined new_subbuf() implementations.
+ * Called by new_page() default implementation, pulled out for
+ * the convenience of user-defined new_page() implementations.
+ *
+ * Will wake up readers after each buf->n_pages_wakeup pages have
+ * been produced. To do no waking up, simply pass 0 into relay
+ * open for this value.
*/
static inline void relay_wakeup_readers(struct rchan_buf *buf)
{
- if (waitqueue_active(&buf->read_wait))
+ size_t wakeup = buf->chan->n_pages_wakeup;
+
+ if (wakeup && (buf->produced % wakeup == 0) &&
+ (waitqueue_active(&buf->read_wait)))
/*
* Calling wake_up_interruptible() from here
* will deadlock if we happen to be logging
@@ -224,17 +227,17 @@ static inline void relay_wakeup_readers(struct
rchan_buf *buf)
}
/**
- * relay_event_toobig - is event too big to fit in a sub-buffer?
+ * relay_event_toobig - is event too big to fit in a page?
* @buf: relay channel buffer
* @length: length of event
*
* Returns 1 if too big, 0 otherwise.
*
- * switch_subbuf() helper function.
+ * switch_page() helper function.
*/
static inline int relay_event_toobig(struct rchan_buf *buf, size_t
length)
{
- return length > buf->chan->subbuf_size;
+ return length > PAGE_SIZE;
}
/**
@@ -242,7 +245,7 @@ static inline int relay_event_toobig(struct
rchan_buf *buf, size_t length)
* @buf: relay channel buffer
* @length: length to add
*
- * switch_subbuf() helper function.
+ * switch_page() helper function.
*/
static inline void relay_update_filesize(struct rchan_buf *buf, size_t
length)
{
@@ -255,14 +258,14 @@ static inline void relay_update_filesize(struct
rchan_buf *buf, size_t length)
}
/**
- * relay_inc_produced - increase number of sub-buffers produced by 1
+ * relay_inc_produced - increase number of pages produced by 1
* @buf: relay channel buffer
*
- * switch_subbuf() helper function.
+ * switch_page() helper function.
*/
static inline void relay_inc_produced(struct rchan_buf *buf)
{
- buf->subbufs_produced++;
+ buf->produced++;
}
/**
@@ -290,8 +293,8 @@ static inline void relay_write(struct rchan *chan,
local_irq_save(flags);
buf = chan->buf[smp_processor_id()];
reserved = buf->data + buf->offset;
- if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
- remainder = chan->cb->switch_subbuf(buf, length, &reserved);
+ if (unlikely(buf->offset + length > PAGE_SIZE)) {
+ remainder = chan->cb->switch_page(buf, length, &reserved);
if (unlikely(!reserved)) {
local_irq_restore(flags);
return;
@@ -325,8 +328,8 @@ static inline void __relay_write(struct rchan *chan,
buf = chan->buf[get_cpu()];
reserved = buf->data + buf->offset;
- if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
- remainder = chan->cb->switch_subbuf(buf, length, &reserved);
+ if (unlikely(buf->offset + length > PAGE_SIZE)) {
+ remainder = chan->cb->switch_page(buf, length, &reserved);
if (unlikely(!reserved)) {
local_irq_restore(flags);
return;
@@ -354,8 +357,8 @@ static inline void *relay_reserve(struct rchan
*chan,
struct rchan_buf *buf = chan->buf[smp_processor_id()];
void *reserved = buf->data + buf->offset;
- if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
- length = chan->cb->switch_subbuf(buf, length, &reserved);
+ if (unlikely(buf->offset + length > PAGE_SIZE)) {
+ length = chan->cb->switch_page(buf, length, &reserved);
if (unlikely(!reserved))
return NULL;
}
@@ -365,17 +368,17 @@ static inline void *relay_reserve(struct rchan
*chan,
}
/**
- * subbuf_start_reserve - reserve bytes at the start of a sub-buffer
+ * page_start_reserve - reserve bytes at the start of a page
* @buf: relay channel buffer
* @length: number of bytes to reserve
*
* Helper function used to reserve bytes at the beginning of
- * a sub-buffer in the subbuf_start() callback.
+ * a page in the new_page() callback.
*/
-static inline void subbuf_start_reserve(struct rchan_buf *buf,
- size_t length)
+static inline void page_start_reserve(struct rchan_buf *buf,
+ size_t length)
{
- BUG_ON(length >= buf->chan->subbuf_size - 1);
+ BUG_ON(length >= PAGE_SIZE - 1);
buf->offset = length;
}
diff --git a/kernel/relay.c b/kernel/relay.c
index 3d06970..137f13f 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -132,31 +132,26 @@ static int relay_mmap_buf(struct rchan_buf *buf,
struct vm_area_struct *vma)
static void *relay_alloc_buf(struct rchan_buf *buf)
{
void *mem;
- unsigned int i, j, n_pages, n_subbuf_pages;
+ unsigned int i, j;
- buf->chan->alloc_size = PAGE_ALIGN(buf->chan->alloc_size);
- n_pages = buf->chan->alloc_size >> PAGE_SHIFT;
- n_subbuf_pages = PAGE_ALIGN(buf->chan->subbuf_size) >> PAGE_SHIFT;
-
- buf->page_array = relay_alloc_page_array(n_pages + n_subbuf_pages);
+ buf->page_array = relay_alloc_page_array(buf->chan->n_pages + 1);
if (!buf->page_array)
return NULL;
- for (i = 0; i < n_pages; i++) {
+ for (i = 0; i < buf->chan->n_pages; i++) {
buf->page_array[i] = alloc_page(GFP_KERNEL);
if (unlikely(!buf->page_array[i]))
goto depopulate;
set_page_private(buf->page_array[i], (unsigned long)buf);
}
- for (i = 0; i < n_subbuf_pages; i++)
- buf->page_array[n_pages + i] = buf->page_array[i];
- mem = vmap(buf->page_array, n_pages + n_subbuf_pages, VM_MAP,
+ buf->page_array[buf->chan->n_pages] = buf->page_array[0];
+ mem = vmap(buf->page_array, buf->chan->n_pages + 1, VM_MAP,
PAGE_KERNEL);
if (!mem)
goto depopulate;
memset(mem, 0, buf->chan->alloc_size);
- buf->page_count = n_pages;
+ buf->page_count = buf->chan->n_pages;
return mem;
depopulate:
@@ -247,7 +242,7 @@ static void relay_remove_buf(struct kref *kref)
*/
static int relay_buf_empty(struct rchan_buf *buf)
{
- return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
+ return (buf->produced - buf->consumed) ? 0 : 1;
}
/**
@@ -258,8 +253,8 @@ static int relay_buf_empty(struct rchan_buf *buf)
*/
int relay_buf_full(struct rchan_buf *buf)
{
- size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
- return (ready >= buf->chan->n_subbufs) ? 1 : 0;
+ size_t ready = buf->produced - buf->consumed;
+ return (ready >= buf->chan->n_pages) ? 1 : 0;
}
EXPORT_SYMBOL_GPL(relay_buf_full);
@@ -308,22 +303,22 @@ static int remove_buf_file_default_callback(struct
dentry *dentry)
}
/*
- * new_subbuf() default callback.
+ * new_page() default callback.
*/
-static void new_subbuf_default_callback(struct rchan_buf *buf,
- void *subbuf)
+static void new_page_default_callback(struct rchan_buf *buf,
+ void *page_data)
{
relay_wakeup_readers(buf);
}
/* relay channel default callbacks */
static struct rchan_callbacks default_channel_callbacks = {
- .new_subbuf = new_subbuf_default_callback,
+ .new_page = new_page_default_callback,
.buf_mapped = buf_mapped_default_callback,
.buf_unmapped = buf_unmapped_default_callback,
.create_buf_file = create_buf_file_default_callback,
.remove_buf_file = remove_buf_file_default_callback,
- .switch_subbuf = relay_switch_subbuf_default_callback,
+ .switch_page = relay_switch_page_default_callback,
};
/**
@@ -354,14 +349,14 @@ static void __relay_reset(struct rchan_buf *buf,
unsigned int init)
} else
del_timer_sync(&buf->timer);
- buf->subbufs_produced = 0;
- buf->subbufs_consumed = 0;
- buf->bytes_consumed = 0;
+ buf->produced = 0;
+ buf->consumed = 0;
+ buf->consumed_offset = 0;
buf->finalized = 0;
buf->data = buf->start;
buf->offset = 0;
- buf->chan->cb->new_subbuf(buf, buf->data);
+ buf->chan->cb->new_page(buf, buf->data);
}
/**
@@ -493,10 +488,10 @@ static void setup_callbacks(struct rchan *chan,
cb->create_buf_file = create_buf_file_default_callback;
if (!cb->remove_buf_file)
cb->remove_buf_file = remove_buf_file_default_callback;
- if (!cb->new_subbuf)
- cb->new_subbuf = new_subbuf_default_callback;
- if (!cb->switch_subbuf)
- cb->switch_subbuf = relay_switch_subbuf_default_callback;
+ if (!cb->new_page)
+ cb->new_page = new_page_default_callback;
+ if (!cb->switch_page)
+ cb->switch_page = relay_switch_page_default_callback;
chan->cb = cb;
}
@@ -546,8 +541,8 @@ static int __cpuinit relay_hotcpu_callback(struct
notifier_block *nb,
* relay_open - create a new relay channel
* @base_filename: base name of files to create, %NULL for buffering
only
* @parent: dentry of parent directory, %NULL for root directory or
buffer
- * @subbuf_size: size of sub-buffers
- * @n_subbufs: number of sub-buffers
+ * @n_pages: number of pages to use for each buffer
+ * @n_pages_wakeup: wakeup readers after this many pages, 0 means never
* @cb: client callback functions
* @private_data: user-defined data
*
@@ -560,8 +555,8 @@ static int __cpuinit relay_hotcpu_callback(struct
notifier_block *nb,
*/
struct rchan *relay_open(const char *base_filename,
struct dentry *parent,
- size_t subbuf_size,
- size_t n_subbufs,
+ size_t n_pages,
+ size_t n_pages_wakeup,
struct rchan_callbacks *cb,
void *private_data,
unsigned long rchan_flags)
@@ -569,7 +564,7 @@ struct rchan *relay_open(const char *base_filename,
unsigned int i;
struct rchan *chan;
- if (!(subbuf_size && n_subbufs))
+ if (!n_pages)
return NULL;
chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
@@ -577,9 +572,9 @@ struct rchan *relay_open(const char *base_filename,
return NULL;
chan->version = RELAYFS_CHANNEL_VERSION;
- chan->n_subbufs = n_subbufs;
- chan->subbuf_size = subbuf_size;
- chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
+ chan->n_pages = n_pages;
+ chan->n_pages_wakeup = n_pages_wakeup;
+ chan->alloc_size = PAGE_SIZE * n_pages;
chan->parent = parent;
chan->flags = rchan_flags;
atomic_set(&chan->dropped, 0);
@@ -704,57 +699,57 @@ int relay_late_setup_files(struct rchan *chan,
return err;
}
-static inline int next_subbuf_free(struct rchan_buf *buf)
+static inline int next_page_free(struct rchan_buf *buf)
{
- size_t full_subbufs;
+ size_t full_pages;
if (buf->chan->flags & RCHAN_MODE_OVERWRITE)
return 1;
- full_subbufs = buf->subbufs_produced - buf->subbufs_consumed;
+ full_pages = buf->produced - buf->consumed;
- return (full_subbufs < buf->chan->n_subbufs - 1);
+ return (full_pages < buf->chan->n_pages - 1);
}
/**
- * relay_switch_subbuf_default_callback - switch to a new sub-buffer
+ * relay_switch_page_default_callback - switch to a new page
* @buf: channel buffer
* @length: size of current event
* @reserved: a pointer to the space reserved
*
* Returns either the length passed in or 0 if full.
*
- * Performs sub-buffer-switch tasks such as invoking callbacks,
+ * Performs page-switch tasks such as invoking callbacks,
* waking up readers, etc.
*/
-size_t relay_switch_subbuf_default_callback(struct rchan_buf *buf,
- size_t length,
- void **reserved)
+size_t relay_switch_page_default_callback(struct rchan_buf *buf,
+ size_t length,
+ void **reserved)
{
- size_t remainder, new_subbuf;
+ size_t remainder, new_page;
void *new_data;
if (unlikely(relay_event_toobig(buf, length)))
goto toobig;
/* don't write anything unless we can write it all. */
- if (!next_subbuf_free(buf)) {
+ if (!next_page_free(buf)) {
if (reserved)
*reserved = NULL;
atomic_inc(&buf->chan->dropped);
return 0;
}
- remainder = length - (buf->chan->subbuf_size - buf->offset);
+ remainder = length - (PAGE_SIZE - buf->offset);
relay_inc_produced(buf);
- relay_update_filesize(buf, buf->chan->subbuf_size + remainder);
+ relay_update_filesize(buf, PAGE_SIZE + remainder);
- new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
- new_data = buf->start + new_subbuf * buf->chan->subbuf_size;
+ new_page = buf->produced % buf->chan->n_pages;
+ new_data = buf->start + new_page * PAGE_SIZE;
buf->data = new_data;
buf->offset = 0; /* remainder will be added by caller */
- buf->chan->cb->new_subbuf(buf, new_data);
+ buf->chan->cb->new_page(buf, new_data);
if (unlikely(relay_event_toobig(buf, length + buf->offset)))
goto toobig;
@@ -764,24 +759,24 @@ toobig:
buf->chan->last_toobig = length;
return 0;
}
-EXPORT_SYMBOL_GPL(relay_switch_subbuf_default_callback);
+EXPORT_SYMBOL_GPL(relay_switch_page_default_callback);
/**
- * relay_subbufs_consumed - update the buffer's sub-buffers-consumed
count
+ * relay_pages_consumed - update the buffer's pages-consumed count
* @chan: the channel
* @cpu: the cpu associated with the channel buffer to update
- * @subbufs_consumed: number of sub-buffers to add to current buf's
count
+ * @consumed: number of pages to add to current buf's count
*
- * Adds to the channel buffer's consumed sub-buffer count.
- * subbufs_consumed should be the number of sub-buffers newly consumed,
+ * Adds to the channel buffer's consumed page count.
+ * consumed should be the number of pages newly consumed,
* not the total consumed.
*
* NOTE. Kernel clients don't need to call this function if the channel
* mode is 'overwrite'.
*/
-void relay_subbufs_consumed(struct rchan *chan,
- unsigned int cpu,
- size_t subbufs_consumed)
+void relay_pages_consumed(struct rchan *chan,
+ unsigned int cpu,
+ size_t consumed)
{
struct rchan_buf *buf;
@@ -792,11 +787,11 @@ void relay_subbufs_consumed(struct rchan *chan,
return;
buf = chan->buf[cpu];
- buf->subbufs_consumed += subbufs_consumed;
- if (buf->subbufs_consumed > buf->subbufs_produced)
- buf->subbufs_consumed = buf->subbufs_produced;
+ buf->consumed += consumed;
+ if (buf->consumed > buf->produced)
+ buf->consumed = buf->produced;
}
-EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
+EXPORT_SYMBOL_GPL(relay_pages_consumed);
/**
* relay_close - close the channel
@@ -821,8 +816,8 @@ void relay_close(struct rchan *chan)
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);
+ "[item size (%Zd) > PAGE_SIZE (%lu)]\n",
+ chan->last_toobig, PAGE_SIZE);
list_del(&chan->list);
kref_put(&chan->kref, relay_destroy_channel);
@@ -839,20 +834,26 @@ EXPORT_SYMBOL_GPL(relay_close);
void relay_flush(struct rchan *chan)
{
unsigned int i;
+ size_t prev_wakeup = chan->n_pages_wakeup;
if (!chan)
return;
+ if (prev_wakeup)
+ chan->n_pages_wakeup = 1;
+
if (chan->flags & RCHAN_GLOBAL_BUFFER && chan->buf[0]) {
- chan->cb->switch_subbuf(chan->buf[0], 0, NULL);
+ chan->cb->switch_page(chan->buf[0], 0, NULL);
+ chan->n_pages_wakeup = prev_wakeup;
return;
}
mutex_lock(&relay_channels_mutex);
for_each_possible_cpu(i)
if (chan->buf[i])
- chan->cb->switch_subbuf(chan->buf[i], 0, NULL);
+ chan->cb->switch_page(chan->buf[i], 0, NULL);
mutex_unlock(&relay_channels_mutex);
+ chan->n_pages_wakeup = prev_wakeup;
}
EXPORT_SYMBOL_GPL(relay_flush);
@@ -932,36 +933,36 @@ static void relay_file_read_consume(struct
rchan_buf *buf,
size_t read_pos,
size_t bytes_consumed)
{
- size_t subbuf_size = buf->chan->subbuf_size;
+ buf->consumed_offset += bytes_consumed;
- buf->bytes_consumed += bytes_consumed;
-
- if (buf->bytes_consumed == subbuf_size) {
- relay_subbufs_consumed(buf->chan, buf->cpu, 1);
- buf->bytes_consumed = 0;
+ if (buf->consumed_offset == PAGE_SIZE) {
+ relay_pages_consumed(buf->chan, buf->cpu, 1);
+ buf->consumed_offset = 0;
}
}
/**
- * relay_file_read_subbuf_avail - return bytes available in sub-buffer
+ * relay_file_read_page_avail - return bytes available in page
* @read_pos: file read position
* @buf: relay channel buffer
*/
-static size_t relay_file_read_subbuf_avail(size_t read_pos,
- struct rchan_buf *buf)
+static size_t relay_file_read_page_avail(size_t read_pos,
+ struct rchan_buf *buf)
{
size_t avail;
- size_t read_subbuf, read_offset, write_subbuf, write_offset;
- size_t subbuf_size = buf->chan->subbuf_size;
+ size_t read_page, read_offset, write_page, write_offset;
- write_subbuf = (buf->data - buf->start) / subbuf_size;
+ write_page = (buf->data - buf->start) / PAGE_SIZE;
write_offset = buf->offset;
- read_subbuf = read_pos / subbuf_size;
- read_offset = read_pos % subbuf_size;
+ read_page = read_pos / PAGE_SIZE;
+ read_offset = read_pos % PAGE_SIZE;
- avail = subbuf_size - read_offset;
+ if (read_page == write_page && read_offset == write_offset)
+ return 0;
- if (read_subbuf == write_subbuf && read_offset < write_offset)
+ avail = PAGE_SIZE - read_offset;
+
+ if (read_page == write_page && read_offset < write_offset)
avail = write_offset - read_offset;
return avail;
@@ -978,11 +979,10 @@ static size_t relay_file_read_subbuf_avail(size_t
read_pos,
static size_t relay_file_read_start_pos(size_t read_pos,
struct rchan_buf *buf)
{
- size_t subbuf_size = buf->chan->subbuf_size;
- size_t consumed = buf->subbufs_consumed % buf->chan->n_subbufs;
+ size_t consumed = buf->consumed % buf->chan->n_pages;
if (!read_pos)
- read_pos = consumed * subbuf_size + buf->bytes_consumed;
+ read_pos = consumed * PAGE_SIZE + buf->consumed_offset;
return read_pos;
}
@@ -999,20 +999,20 @@ static size_t relay_file_read_end_pos(struct
rchan_buf *buf,
{
size_t end_pos = read_pos + count;
- if (end_pos >= buf->chan->subbuf_size * buf->chan->n_subbufs)
+ if (end_pos >= PAGE_SIZE * buf->chan->n_pages)
end_pos = 0;
return end_pos;
}
/*
- * subbuf_read_actor - read up to one subbuf's worth of data
+ * page_read_actor - read up to one page's worth of data
*/
-static int subbuf_read_actor(size_t read_start,
- struct rchan_buf *buf,
- size_t avail,
- read_descriptor_t *desc,
- read_actor_t actor)
+static int page_read_actor(size_t read_start,
+ struct rchan_buf *buf,
+ size_t avail,
+ read_descriptor_t *desc,
+ read_actor_t actor)
{
void *from;
int ret = 0;
@@ -1030,19 +1030,19 @@ static int subbuf_read_actor(size_t read_start,
return ret;
}
-typedef int (*subbuf_actor_t) (size_t read_start,
- struct rchan_buf *buf,
- size_t avail,
- read_descriptor_t *desc,
- read_actor_t actor);
+typedef int (*page_actor_t) (size_t read_start,
+ struct rchan_buf *buf,
+ size_t avail,
+ read_descriptor_t *desc,
+ read_actor_t actor);
/*
- * relay_file_read_subbufs - read count bytes, bridging subbuf
boundaries
+ * relay_file_read_pages - read count bytes, bridging page boundaries
*/
-static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos,
- subbuf_actor_t subbuf_actor,
- read_actor_t actor,
- read_descriptor_t *desc)
+static ssize_t relay_file_read_pages(struct file *filp, loff_t *ppos,
+ page_actor_t page_actor,
+ read_actor_t actor,
+ read_descriptor_t *desc)
{
struct rchan_buf *buf = filp->private_data;
size_t read_start, avail;
@@ -1054,12 +1054,12 @@ static ssize_t relay_file_read_subbufs(struct
file *filp, loff_t *ppos,
mutex_lock(&filp->f_path.dentry->d_inode->i_mutex);
do {
read_start = relay_file_read_start_pos(*ppos, buf);
- avail = relay_file_read_subbuf_avail(read_start, buf);
+ avail = relay_file_read_page_avail(read_start, buf);
if (!avail)
break;
avail = min(desc->count, avail);
- ret = subbuf_actor(read_start, buf, avail, desc, actor);
+ ret = page_actor(read_start, buf, avail, desc, actor);
if (desc->error < 0)
break;
@@ -1083,17 +1083,17 @@ static ssize_t relay_file_read(struct file
*filp,
desc.count = count;
desc.arg.buf = buffer;
desc.error = 0;
- return relay_file_read_subbufs(filp, ppos, subbuf_read_actor,
- NULL, &desc);
+ return relay_file_read_pages(filp, ppos, page_read_actor,
+ NULL, &desc);
}
static void relay_consume_bytes(struct rchan_buf *rbuf, int
bytes_consumed)
{
- rbuf->bytes_consumed += bytes_consumed;
+ rbuf->consumed_offset += bytes_consumed;
- if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) {
- relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1);
- rbuf->bytes_consumed %= rbuf->chan->subbuf_size;
+ if (rbuf->consumed_offset >= PAGE_SIZE) {
+ relay_pages_consumed(rbuf->chan, rbuf->cpu, 1);
+ rbuf->consumed_offset %= PAGE_SIZE;
}
}
@@ -1121,17 +1121,16 @@ static void relay_page_release(struct
splice_pipe_desc *spd, unsigned int i)
}
/*
- * subbuf_splice_actor - splice up to one subbuf's worth of data
+ * page_splice_actor - splice available data
*/
-static int subbuf_splice_actor(struct file *in,
- loff_t *ppos,
- struct pipe_inode_info *pipe,
- size_t len,
- unsigned int flags)
+static int page_splice_actor(struct file *in,
+ loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len,
+ unsigned int flags)
{
- unsigned int pidx, poff, total_len, subbuf_pages, nr_pages, ret;
+ unsigned int pidx, poff, total_len, buf_pages, nr_pages, ret;
struct rchan_buf *rbuf = in->private_data;
- unsigned int subbuf_size = rbuf->chan->subbuf_size;
uint64_t pos = (uint64_t) *ppos;
uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size;
size_t read_start = (size_t) do_div(pos, alloc_size);
@@ -1146,20 +1145,14 @@ static int subbuf_splice_actor(struct file *in,
.spd_release = relay_page_release,
};
- if (rbuf->subbufs_produced == rbuf->subbufs_consumed &&
- rbuf->offset == rbuf->bytes_consumed)
+ if (rbuf->produced == rbuf->consumed &&
+ rbuf->offset == rbuf->consumed_offset)
return 0;
- /*
- * Adjust read len, if longer than what is available
- */
- if (len > (subbuf_size - read_start % subbuf_size))
- len = subbuf_size - read_start % subbuf_size;
-
- subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
- pidx = (read_start / PAGE_SIZE) % subbuf_pages;
+ buf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
+ pidx = (read_start / PAGE_SIZE) % buf_pages;
poff = read_start & ~PAGE_MASK;
- nr_pages = min_t(unsigned int, subbuf_pages, PIPE_BUFFERS);
+ nr_pages = min_t(unsigned int, buf_pages, PIPE_BUFFERS);
for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) {
unsigned int this_len;
@@ -1177,7 +1170,7 @@ static int subbuf_splice_actor(struct file *in,
len -= this_len;
total_len += this_len;
poff = 0;
- pidx = (pidx + 1) % subbuf_pages;
+ pidx = (pidx + 1) % buf_pages;
}
ret = splice_to_pipe(pipe, &spd);
@@ -1198,7 +1191,7 @@ static ssize_t relay_file_splice_read(struct file
*in,
spliced = 0;
while (len && !spliced) {
- ret = subbuf_splice_actor(in, ppos, pipe, len, flags);
+ ret = page_splice_actor(in, ppos, pipe, len, flags);
if (ret < 0)
break;
else if (!ret) {
diff --git a/virt/kvm/kvm_trace.c b/virt/kvm/kvm_trace.c
index 293a3c2..9373b34 100644
--- a/virt/kvm/kvm_trace.c
+++ b/virt/kvm/kvm_trace.c
@@ -28,7 +28,7 @@ struct kvm_trace {
int trace_state;
struct rchan *rchan;
struct dentry *lost_file;
- int first_subbuf;
+ int first_page;
};
static struct kvm_trace *kvm_trace;
@@ -105,21 +105,21 @@ DEFINE_SIMPLE_ATTRIBUTE(kvm_trace_lost_ops,
lost_records_get, NULL, "%llu\n");
* many times we encountered a full subbuffer, to tell user space app
the
* lost records there were.
*/
-static void kvm_new_subbuf_callback(struct rchan_buf *buf,
- void *subbuf)
+static void kvm_new_page_callback(struct rchan_buf *buf,
+ void *page_data)
{
struct kvm_trace *kt = buf->chan->private_data;
relay_wakeup_readers(buf);
- if (kt->first_subbuf) {
+ if (kt->first_page) {
/*
* executed only once when the channel is opened
* save metadata as first record
*/
- subbuf_start_reserve(buf, sizeof(u32));
- *(u32 *)subbuf = 0x12345678;
- kt->first_subbuf = 0;
+ page_start_reserve(buf, sizeof(u32));
+ *(u32 *)page_data = 0x12345678;
+ kt->first_page = 0;
}
}
@@ -139,7 +139,7 @@ static int kvm_remove_buf_file_callback(struct
dentry *dentry)
}
static struct rchan_callbacks kvm_relay_callbacks = {
- .new_subbuf = kvm_new_subbuf_callback,
+ .new_page = kvm_new_page_callback,
.create_buf_file = kvm_create_buf_file_callack,
.remove_buf_file = kvm_remove_buf_file_callback,
};
@@ -148,6 +148,7 @@ static int do_kvm_trace_enable(struct
kvm_user_trace_setup *kuts)
{
struct kvm_trace *kt;
int i, r = -ENOMEM;
+ int n_pages, n_pages_wakeup;
if (!kuts->buf_size || !kuts->buf_nr)
return -EINVAL;
@@ -157,14 +158,16 @@ static int do_kvm_trace_enable(struct
kvm_user_trace_setup *kuts)
goto err;
r = -EIO;
- kt->first_subbuf = 1;
+ kt->first_page = 1;
kt->lost_file = debugfs_create_file("lost_records", 0444,
kvm_debugfs_dir,
kt, &kvm_trace_lost_ops);
if (!kt->lost_file)
goto err;
- kt->rchan = relay_open("trace", kvm_debugfs_dir, kuts->buf_size,
- kuts->buf_nr, &kvm_relay_callbacks, kt, 0UL);
+ n_pages = (kuts->buf_size * kuts->buf_nr) / PAGE_SIZE;
+ n_pages_wakeup = kuts->buf_size / PAGE_SIZE;
+ kt->rchan = relay_open("trace", kvm_debugfs_dir, n_pages,
+ n_pages_wakeup, &kvm_relay_callbacks, kt, 0UL);
if (!kt->rchan)
goto err;
--
1.5.3.5
--
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