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Date: Mon, 29 Sep 2008 00:40:51 -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 11/11] relay - Remove vmap of relay buffers.
Remove vmap of relay buffers.
Also removes relay_reserve and switches callers over to relay_write.
Signed-off-by: Tom Zanussi <zanussi@...cast.net>
---
block/blktrace.c | 8 ++++-
include/linux/relay.h | 47 +++++++++---------------------------
kernel/relay.c | 63 +++++++++++++++++++++---------------------------
3 files changed, 46 insertions(+), 72 deletions(-)
diff --git a/block/blktrace.c b/block/blktrace.c
index 84a9cb4..f60665e 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -35,7 +35,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
{
struct blk_io_trace *t;
- t = relay_reserve(bt->rchan, sizeof(*t) + len);
+ t = kmalloc(sizeof(*t) + len, GFP_KERNEL);
if (t) {
const int cpu = smp_processor_id();
@@ -47,6 +47,8 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
t->cpu = cpu;
t->pdu_len = len;
memcpy((void *) t + sizeof(*t), data, len);
+ relay_write(bt->rchan, t, sizeof(*t) + len);
+ kfree(t);
}
}
@@ -166,7 +168,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
if (unlikely(tsk->btrace_seq != blktrace_seq))
trace_note_tsk(bt, tsk);
- t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
+ t = kmalloc(sizeof(*t) + pdu_len, GFP_KERNEL);
if (t) {
cpu = smp_processor_id();
sequence = per_cpu_ptr(bt->sequence, cpu);
@@ -185,6 +187,8 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
if (pdu_len)
memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
+ relay_write(bt->rchan, t, sizeof(*t) + pdu_len);
+ kfree(t);
}
local_irq_restore(flags);
diff --git a/include/linux/relay.h b/include/linux/relay.h
index e0b1730..35a6e8c 100644
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -35,8 +35,8 @@
*/
struct rchan_buf
{
- void *start; /* start of channel buffer */
- void *data; /* start of current page */
+ void *data; /* address of current page */
+ struct page *page; /* current page */
size_t offset; /* current offset into page */
size_t produced; /* count of pages produced */
size_t consumed; /* count of pages consumed */
@@ -288,17 +288,19 @@ static inline void relay_write(struct rchan *chan,
size_t remainder = length;
struct rchan_buf *buf;
unsigned long flags;
- void *reserved;
+ void *reserved, *reserved2;
local_irq_save(flags);
buf = chan->buf[smp_processor_id()];
reserved = buf->data + buf->offset;
if (unlikely(buf->offset + length > PAGE_SIZE)) {
- remainder = chan->cb->switch_page(buf, length, &reserved);
- if (unlikely(!reserved)) {
+ remainder = chan->cb->switch_page(buf, length, &reserved2);
+ if (unlikely(!reserved2)) {
local_irq_restore(flags);
return;
}
+ length -= remainder;
+ memcpy(reserved2, data + length, remainder);
}
memcpy(reserved, data, length);
buf->offset += remainder;
@@ -324,16 +326,18 @@ static inline void __relay_write(struct rchan *chan,
size_t remainder = length;
struct rchan_buf *buf;
unsigned long flags;
- void *reserved;
+ void *reserved, *reserved2;
buf = chan->buf[get_cpu()];
reserved = buf->data + buf->offset;
if (unlikely(buf->offset + length > PAGE_SIZE)) {
- remainder = chan->cb->switch_page(buf, length, &reserved);
- if (unlikely(!reserved)) {
+ remainder = chan->cb->switch_page(buf, length, &reserved2);
+ if (unlikely(!reserved2)) {
local_irq_restore(flags);
return;
}
+ length -= remainder;
+ memcpy(reserved2, data + length, remainder);
}
memcpy(reserved, data, length);
buf->offset += remainder;
@@ -341,33 +345,6 @@ static inline void __relay_write(struct rchan *chan,
}
/**
- * relay_reserve - reserve slot in channel buffer
- * @chan: relay channel
- * @length: number of bytes to reserve
- *
- * Returns pointer to reserved slot, NULL if full.
- *
- * Reserves a slot in the current cpu's channel buffer.
- * Does not protect the buffer at all - caller must provide
- * appropriate synchronization.
- */
-static inline void *relay_reserve(struct rchan *chan,
- size_t length)
-{
- struct rchan_buf *buf = chan->buf[smp_processor_id()];
- void *reserved = buf->data + buf->offset;
-
- if (unlikely(buf->offset + length > PAGE_SIZE)) {
- length = chan->cb->switch_page(buf, length, &reserved);
- if (unlikely(!reserved))
- return NULL;
- }
- buf->offset += length;
-
- return reserved;
-}
-
-/**
* page_start_reserve - reserve bytes at the start of a page
* @buf: relay channel buffer
* @length: number of bytes to reserve
diff --git a/kernel/relay.c b/kernel/relay.c
index 137f13f..1a151b8 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -48,7 +48,8 @@ static int relay_buf_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
if (!buf)
return VM_FAULT_OOM;
- page = vmalloc_to_page(buf->start + (pgoff << PAGE_SHIFT));
+ page = buf->page_array[pgoff];
+
if (!page)
return VM_FAULT_SIGBUS;
get_page(page);
@@ -126,39 +127,32 @@ static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
* relay_alloc_buf - allocate a channel buffer
* @buf: the buffer struct
*
- * Returns a pointer to the resulting buffer, %NULL if unsuccessful. The
- * passed in size will get page aligned, if it isn't already.
+ * Returns 0 if successful.
*/
-static void *relay_alloc_buf(struct rchan_buf *buf)
+static int relay_alloc_buf(struct rchan_buf *buf)
{
- void *mem;
unsigned int i, j;
buf->page_array = relay_alloc_page_array(buf->chan->n_pages + 1);
if (!buf->page_array)
- return NULL;
+ return -ENOMEM;
for (i = 0; i < buf->chan->n_pages; i++) {
- buf->page_array[i] = alloc_page(GFP_KERNEL);
+ buf->page_array[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (unlikely(!buf->page_array[i]))
goto depopulate;
set_page_private(buf->page_array[i], (unsigned long)buf);
}
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 = buf->chan->n_pages;
- return mem;
+ return 0;
depopulate:
for (j = 0; j < i; j++)
__free_page(buf->page_array[j]);
relay_free_page_array(buf->page_array);
- return NULL;
+ return -ENOMEM;
}
/**
@@ -176,8 +170,7 @@ static struct rchan_buf *relay_create_buf(struct rchan *chan)
buf->chan = chan;
kref_get(&buf->chan->kref);
- buf->start = relay_alloc_buf(buf);
- if (!buf->start)
+ if (relay_alloc_buf(buf))
goto free_buf;
return buf;
@@ -208,12 +201,10 @@ static void relay_destroy_buf(struct rchan_buf *buf)
struct rchan *chan = buf->chan;
unsigned int i;
- if (likely(buf->start)) {
- vunmap(buf->start);
- for (i = 0; i < buf->page_count; i++)
- __free_page(buf->page_array[i]);
- relay_free_page_array(buf->page_array);
- }
+ for (i = 0; i < buf->page_count; i++)
+ __free_page(buf->page_array[i]);
+ relay_free_page_array(buf->page_array);
+
chan->buf[buf->cpu] = NULL;
kfree(buf);
kref_put(&chan->kref, relay_destroy_channel);
@@ -353,7 +344,8 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init)
buf->consumed = 0;
buf->consumed_offset = 0;
buf->finalized = 0;
- buf->data = buf->start;
+ buf->page = buf->page_array[0];
+ buf->data = page_address(buf->page);
buf->offset = 0;
buf->chan->cb->new_page(buf, buf->data);
@@ -726,8 +718,7 @@ size_t relay_switch_page_default_callback(struct rchan_buf *buf,
size_t length,
void **reserved)
{
- size_t remainder, new_page;
- void *new_data;
+ size_t remainder;
if (unlikely(relay_event_toobig(buf, length)))
goto toobig;
@@ -744,16 +735,18 @@ size_t relay_switch_page_default_callback(struct rchan_buf *buf,
relay_inc_produced(buf);
relay_update_filesize(buf, PAGE_SIZE + remainder);
- new_page = buf->produced % buf->chan->n_pages;
- new_data = buf->start + new_page * PAGE_SIZE;
+ buf->page = buf->page_array[buf->produced % buf->chan->n_pages];
+ buf->data = page_address(buf->page);
- buf->data = new_data;
buf->offset = 0; /* remainder will be added by caller */
- buf->chan->cb->new_page(buf, new_data);
+ buf->chan->cb->new_page(buf, buf->data);
if (unlikely(relay_event_toobig(buf, length + buf->offset)))
goto toobig;
+ if (reserved)
+ *reserved = buf->data;
+
return remainder;
toobig:
buf->chan->last_toobig = length;
@@ -950,11 +943,12 @@ static size_t relay_file_read_page_avail(size_t read_pos,
struct rchan_buf *buf)
{
size_t avail;
- size_t read_page, read_offset, write_page, write_offset;
+ struct page *read_page, *write_page;
+ size_t read_offset, write_offset;
- write_page = (buf->data - buf->start) / PAGE_SIZE;
+ write_page = buf->page;
write_offset = buf->offset;
- read_page = read_pos / PAGE_SIZE;
+ read_page = buf->page_array[read_pos / PAGE_SIZE];
read_offset = read_pos % PAGE_SIZE;
if (read_page == write_page && read_offset == write_offset)
@@ -1017,7 +1011,8 @@ static int page_read_actor(size_t read_start,
void *from;
int ret = 0;
- from = buf->start + read_start;
+ from = page_address(buf->page_array[read_start / PAGE_SIZE]);
+ from += read_start % PAGE_SIZE;
ret = avail;
if (copy_to_user(desc->arg.buf, from, avail)) {
desc->error = -EFAULT;
@@ -1057,12 +1052,10 @@ static ssize_t relay_file_read_pages(struct file *filp, loff_t *ppos,
avail = relay_file_read_page_avail(read_start, buf);
if (!avail)
break;
-
avail = min(desc->count, avail);
ret = page_actor(read_start, buf, avail, desc, actor);
if (desc->error < 0)
break;
-
if (ret) {
relay_file_read_consume(buf, read_start, ret);
*ppos = relay_file_read_end_pos(buf, read_start, ret);
--
1.5.3.5
--
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