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[PATCH -mm] relayfs: support larger relay buffer
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: David Wilder <dwilder at us dot ibm dot com>, Tom Zanussi <zanussi at comcast dot net>, Andrew Morton <akpm at linux-foundation dot org>
- Cc: systemtap-ml <systemtap at sources dot redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>
- Date: Tue, 15 Apr 2008 11:27:27 -0400
- Subject: [PATCH -mm] relayfs: support larger relay buffer
Use vmalloc() and memset() instead of kcalloc() to allocate a page* array
when the array size is bigger than one page. This enables relayfs to support
bigger relay buffers than 64MB on 4k-page system, 512MB on 16k-page system.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
---
This is useful for a 64-bit system which has a plenty of memory (tens of
giga bytes) and a large kernel memory space.
I tested it on x86-64 and ia64.
kernel/relay.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
Index: 2.6.25-rc8-mm2/kernel/relay.c
===================================================================
--- 2.6.25-rc8-mm2.orig/kernel/relay.c
+++ 2.6.25-rc8-mm2/kernel/relay.c
@@ -104,12 +104,20 @@ static int relay_mmap_buf(struct rchan_b
static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
{
void *mem;
- unsigned int i, j, n_pages;
+ unsigned int i, j, n_pages, pa_size;
*size = PAGE_ALIGN(*size);
n_pages = *size >> PAGE_SHIFT;
+ pa_size = n_pages * sizeof(struct page *);
- buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
+ if (pa_size > PAGE_SIZE) {
+ buf->page_array = vmalloc(pa_size);
+ if (buf->page_array)
+ memset(buf->page_array, 0, pa_size);
+ } else {
+ buf->page_array = kcalloc(n_pages, sizeof(struct page *),
+ GFP_KERNEL);
+ }
if (!buf->page_array)
return NULL;
@@ -130,7 +138,10 @@ static void *relay_alloc_buf(struct rcha
depopulate:
for (j = 0; j < i; j++)
__free_page(buf->page_array[j]);
- kfree(buf->page_array);
+ if (pa_size > PAGE_SIZE)
+ vfree(buf->page_array);
+ else
+ kfree(buf->page_array);
return NULL;
}
@@ -189,7 +200,10 @@ static void relay_destroy_buf(struct rch
vunmap(buf->start);
for (i = 0; i < buf->page_count; i++)
__free_page(buf->page_array[i]);
- kfree(buf->page_array);
+ if (buf->page_count * sizeof(struct page *) > PAGE_SIZE)
+ vfree(buf->page_array);
+ else
+ kfree(buf->page_array);
}
chan->buf[buf->cpu] = NULL;
kfree(buf->padding);
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com