From: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Subject: [PATCH] proc: add /proc/kpageorder interface
This makes page order information available to the user-space.
Cc: Matt Mackall <mpm@xxxxxxxxxxx>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
fs/proc/page.c | 48 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/mm.h | 11 ++++++++++
kernel/events/internal.h | 8 +++----
kernel/events/ring_buffer.c | 10 ++++-----
mm/internal.h | 11 ----------
5 files changed, 68 insertions(+), 20 deletions(-)
Index: b/fs/proc/page.c
===================================================================
--- a/fs/proc/page.c 2012-05-31 16:24:12.323109710 +0200
+++ b/fs/proc/page.c 2012-05-31 16:33:35.819109657 +0200
@@ -207,10 +207,58 @@ static const struct file_operations proc
.read = kpageflags_read,
};
+static ssize_t kpageorder_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 porder;
+
+ pfn = src / KPMSIZE;
+ count = min_t(unsigned long, count,
+ ((ARCH_PFN_OFFSET + max_pfn) * KPMSIZE) - src);
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+
+ while (count > 0) {
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ else
+ ppage = NULL;
+ if (!ppage || !PageBuddy(ppage))
+ porder = 0;
+ else
+ porder = page_order(ppage);
+
+ if (put_user(porder, out)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ pfn++;
+ out++;
+ count -= KPMSIZE;
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct file_operations proc_kpageorder_operations = {
+ .llseek = mem_lseek,
+ .read = kpageorder_read,
+};
+
static int __init proc_page_init(void)
{
proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
+ proc_create("kpageorder", S_IRUSR, NULL, &proc_kpageorder_operations);
return 0;
}
module_init(proc_page_init);
Index: b/include/linux/mm.h
===================================================================
--- a/include/linux/mm.h 2012-05-31 16:24:12.295109717 +0200
+++ b/include/linux/mm.h 2012-05-31 16:30:49.215109568 +0200
@@ -250,6 +250,17 @@ struct inode;
#define set_page_private(page, v) ((page)->private = (v))
/*
+ * function for dealing with page's order in buddy system.
+ * zone->lock is already acquired when we use these.
+ * So, we don't need atomic page->flags operations here.
+ */
+static inline unsigned long page_order(struct page *page)
+{
+ /* PageBuddy() must be checked by the caller */
+ return page_private(page);
+}
+
+/*
* FIXME: take this include out, include page-flags.h in
* files which need it (119 of them)
*/
Index: b/kernel/events/internal.h
===================================================================
--- a/kernel/events/internal.h 2012-05-31 16:24:12.307109719 +0200
+++ b/kernel/events/internal.h 2012-05-31 16:30:49.215109568 +0200
@@ -58,14 +58,14 @@ perf_mmap_to_page(struct ring_buffer *rb
* Required for architectures that have d-cache aliasing issues.
*/
-static inline int page_order(struct ring_buffer *rb)
+static inline int rb_page_order(struct ring_buffer *rb)
{
return rb->page_order;
}
#else
-static inline int page_order(struct ring_buffer *rb)
+static inline int rb_page_order(struct ring_buffer *rb)
{
return 0;
}
@@ -73,7 +73,7 @@ static inline int page_order(struct ring
static inline unsigned long perf_data_size(struct ring_buffer *rb)
{
- return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
+ return rb->nr_pages << (PAGE_SHIFT + rb_page_order(rb));
}
static inline void
@@ -95,7 +95,7 @@ __output_copy(struct perf_output_handle
handle->page++;
handle->page &= rb->nr_pages - 1;
handle->addr = rb->data_pages[handle->page];
- handle->size = PAGE_SIZE << page_order(rb);
+ handle->size = PAGE_SIZE << rb_page_order(rb);
}
} while (len);
}
Index: b/kernel/events/ring_buffer.c
===================================================================
--- a/kernel/events/ring_buffer.c 2012-05-31 16:24:12.315109715 +0200
+++ b/kernel/events/ring_buffer.c 2012-05-31 16:30:49.215109568 +0200
@@ -154,12 +154,12 @@ int perf_output_begin(struct perf_output
if (head - local_read(&rb->wakeup) > rb->watermark)
local_add(rb->watermark, &rb->wakeup);
- handle->page = offset >> (PAGE_SHIFT + page_order(rb));
+ handle->page = offset >> (PAGE_SHIFT + rb_page_order(rb));
handle->page &= rb->nr_pages - 1;
- handle->size = offset & ((PAGE_SIZE << page_order(rb)) - 1);
+ handle->size = offset & ((PAGE_SIZE << rb_page_order(rb)) - 1);
handle->addr = rb->data_pages[handle->page];
handle->addr += handle->size;
- handle->size = (PAGE_SIZE << page_order(rb)) - handle->size;
+ handle->size = (PAGE_SIZE << rb_page_order(rb)) - handle->size;
if (have_lost) {
lost_event.header.type = PERF_RECORD_LOST;
@@ -310,7 +310,7 @@ void rb_free(struct ring_buffer *rb)
struct page *
perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff)
{
- if (pgoff > (1UL << page_order(rb)))
+ if (pgoff > (1UL << rb_page_order(rb)))
return NULL;
return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE);
@@ -330,7 +330,7 @@ static void rb_free_work(struct work_str
int i, nr;
rb = container_of(work, struct ring_buffer, work);
- nr = 1 << page_order(rb);
+ nr = 1 << rb_page_order(rb);
base = rb->user_page;
for (i = 0; i < nr + 1; i++)
Index: b/mm/internal.h
===================================================================
--- a/mm/internal.h 2012-05-31 16:24:12.299109722 +0200
+++ b/mm/internal.h 2012-05-31 16:30:49.215109568 +0200
@@ -141,17 +141,6 @@ isolate_migratepages_range(struct zone *
#endif
-/*
- * function for dealing with page's order in buddy system.
- * zone->lock is already acquired when we use these.
- * So, we don't need atomic page->flags operations here.
- */
-static inline unsigned long page_order(struct page *page)
-{
- /* PageBuddy() must be checked by the caller */
- return page_private(page);
-}
-
/* mm/util.c */
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node *rb_parent);
--
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