* [ltt-dev] [PATCH 2/2] ltt-relay: cache page's address
@ 2009-02-27 8:11 Lai Jiangshan
2009-02-27 16:26 ` Mathieu Desnoyers
0 siblings, 1 reply; 2+ messages in thread
From: Lai Jiangshan @ 2009-02-27 8:11 UTC (permalink / raw)
page_address is not fast in some systems,
we should cache it.
Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
---
diff --git a/include/linux/ltt-relay.h b/include/linux/ltt-relay.h
index 8d23352..20908ec 100644
--- a/include/linux/ltt-relay.h
+++ b/include/linux/ltt-relay.h
@@ -34,6 +34,7 @@ struct rchan_buf;
struct buf_page {
struct page *page;
+ void *virt; /* page address of the struct page */
size_t offset; /* page offset in the buffer */
struct list_head list; /* buffer linked list */
};
@@ -275,8 +276,7 @@ static inline int ltt_relay_write(struct rchan_buf *buf, size_t offset,
page = ltt_relay_cache_page(buf, &buf->wpage, page, offset);
pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- ltt_relay_do_copy(page_address(page->page)
- + (offset & ~PAGE_MASK), src, pagecpy);
+ ltt_relay_do_copy(page->virt + (offset & ~PAGE_MASK), src, pagecpy);
if (unlikely(len != pagecpy))
_ltt_relay_write(buf, offset, src, len, page, pagecpy);
diff --git a/ltt/ltt-relay-alloc.c b/ltt/ltt-relay-alloc.c
index 91c12d4..a10fa4b 100644
--- a/ltt/ltt-relay-alloc.c
+++ b/ltt/ltt-relay-alloc.c
@@ -54,6 +54,7 @@ static int relay_alloc_buf(struct rchan_buf *buf, size_t *size)
goto depopulate;
}
list_add_tail(&buf_page->list, &buf->pages);
+ buf_page->virt = page_address(buf_page->page);
buf_page->offset = (size_t)i << PAGE_SHIFT;
set_page_private(buf_page->page, (unsigned long)buf_page);
if (i == 0) {
@@ -524,8 +525,8 @@ void _ltt_relay_write(struct rchan_buf *buf, size_t offset,
page = ltt_relay_cache_page(buf, &buf->wpage, page, offset);
pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- ltt_relay_do_copy(page_address(page->page)
- + (offset & ~PAGE_MASK), src, pagecpy);
+ ltt_relay_do_copy(page->virt
+ + (offset & ~PAGE_MASK), src, pagecpy);
} while (unlikely(len != pagecpy));
}
EXPORT_SYMBOL_GPL(_ltt_relay_write);
@@ -551,8 +552,7 @@ int ltt_relay_read(struct rchan_buf *buf, size_t offset,
for (;;) {
page = ltt_relay_cache_page(buf, &buf->rpage, page, offset);
pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
- memcpy(dest, page_address(page->page) + (offset & ~PAGE_MASK),
- pagecpy);
+ memcpy(dest, page->virt + (offset & ~PAGE_MASK), pagecpy);
len -= pagecpy;
if (likely(!len))
break;
@@ -605,7 +605,7 @@ void *ltt_relay_offset_address(struct rchan_buf *buf, size_t offset)
if (offset < page->offset || offset >= page->offset + PAGE_SIZE)
buf->hpage[odd] = page = buf->wpage;
page = ltt_relay_cache_page(buf, &buf->hpage[odd], page, offset);
- return page_address(page->page) + (offset & ~PAGE_MASK);
+ return page->virt + (offset & ~PAGE_MASK);
}
EXPORT_SYMBOL_GPL(ltt_relay_offset_address);
^ permalink raw reply [flat|nested] 2+ messages in thread
* [ltt-dev] [PATCH 2/2] ltt-relay: cache page's address
2009-02-27 8:11 [ltt-dev] [PATCH 2/2] ltt-relay: cache page's address Lai Jiangshan
@ 2009-02-27 16:26 ` Mathieu Desnoyers
0 siblings, 0 replies; 2+ messages in thread
From: Mathieu Desnoyers @ 2009-02-27 16:26 UTC (permalink / raw)
* Lai Jiangshan (laijs at cn.fujitsu.com) wrote:
>
> page_address is not fast in some systems,
> we should cache it.
>
Ah ! great patch. I look forward to measure the performance improvements
this patch provides.
Will merge, thanks,
Mathieu
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at polymtl.ca>
> Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
> ---
> diff --git a/include/linux/ltt-relay.h b/include/linux/ltt-relay.h
> index 8d23352..20908ec 100644
> --- a/include/linux/ltt-relay.h
> +++ b/include/linux/ltt-relay.h
> @@ -34,6 +34,7 @@ struct rchan_buf;
>
> struct buf_page {
> struct page *page;
> + void *virt; /* page address of the struct page */
> size_t offset; /* page offset in the buffer */
> struct list_head list; /* buffer linked list */
> };
> @@ -275,8 +276,7 @@ static inline int ltt_relay_write(struct rchan_buf *buf, size_t offset,
>
> page = ltt_relay_cache_page(buf, &buf->wpage, page, offset);
> pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
> - ltt_relay_do_copy(page_address(page->page)
> - + (offset & ~PAGE_MASK), src, pagecpy);
> + ltt_relay_do_copy(page->virt + (offset & ~PAGE_MASK), src, pagecpy);
>
> if (unlikely(len != pagecpy))
> _ltt_relay_write(buf, offset, src, len, page, pagecpy);
> diff --git a/ltt/ltt-relay-alloc.c b/ltt/ltt-relay-alloc.c
> index 91c12d4..a10fa4b 100644
> --- a/ltt/ltt-relay-alloc.c
> +++ b/ltt/ltt-relay-alloc.c
> @@ -54,6 +54,7 @@ static int relay_alloc_buf(struct rchan_buf *buf, size_t *size)
> goto depopulate;
> }
> list_add_tail(&buf_page->list, &buf->pages);
> + buf_page->virt = page_address(buf_page->page);
> buf_page->offset = (size_t)i << PAGE_SHIFT;
> set_page_private(buf_page->page, (unsigned long)buf_page);
> if (i == 0) {
> @@ -524,8 +525,8 @@ void _ltt_relay_write(struct rchan_buf *buf, size_t offset,
>
> page = ltt_relay_cache_page(buf, &buf->wpage, page, offset);
> pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
> - ltt_relay_do_copy(page_address(page->page)
> - + (offset & ~PAGE_MASK), src, pagecpy);
> + ltt_relay_do_copy(page->virt
> + + (offset & ~PAGE_MASK), src, pagecpy);
> } while (unlikely(len != pagecpy));
> }
> EXPORT_SYMBOL_GPL(_ltt_relay_write);
> @@ -551,8 +552,7 @@ int ltt_relay_read(struct rchan_buf *buf, size_t offset,
> for (;;) {
> page = ltt_relay_cache_page(buf, &buf->rpage, page, offset);
> pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
> - memcpy(dest, page_address(page->page) + (offset & ~PAGE_MASK),
> - pagecpy);
> + memcpy(dest, page->virt + (offset & ~PAGE_MASK), pagecpy);
> len -= pagecpy;
> if (likely(!len))
> break;
> @@ -605,7 +605,7 @@ void *ltt_relay_offset_address(struct rchan_buf *buf, size_t offset)
> if (offset < page->offset || offset >= page->offset + PAGE_SIZE)
> buf->hpage[odd] = page = buf->wpage;
> page = ltt_relay_cache_page(buf, &buf->hpage[odd], page, offset);
> - return page_address(page->page) + (offset & ~PAGE_MASK);
> + return page->virt + (offset & ~PAGE_MASK);
> }
> EXPORT_SYMBOL_GPL(ltt_relay_offset_address);
>
>
>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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