diff options
| author | Sergei Rogachev <rogachevsergei@gmail.com> | 2015-02-11 15:28:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-11 17:06:07 -0800 |
| commit | 94f759d62b2c6a9d124b0622077b1ddcfac43fb5 (patch) | |
| tree | 962eb704c95c064dbfcdd59b4033f490c4ede34a /mm | |
| parent | 740a5ddb0e0d2ef3bd0a80ae027bf9d211b8c82d (diff) | |
mm/page_owner.c: remove unnecessary stack_trace field
Page owner uses the page_ext structure to keep meta-information for every
page in the system. The structure also contains a field of type 'struct
stack_trace', page owner uses this field during invocation of the function
save_stack_trace. It is easy to notice that keeping a copy of this
structure for every page in the system is very inefficiently in terms of
memory.
The patch removes this unnecessary field of page_ext and forces page owner
to use a stack_trace structure allocated on the stack.
[akpm@linux-foundation.org: use struct initializers]
Signed-off-by: Sergei Rogachev <rogachevsergei@gmail.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_owner.c | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c index 9ab4a9b5bc09..0993f5f36b01 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -59,20 +59,19 @@ void __reset_page_owner(struct page *page, unsigned int order) void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) { - struct page_ext *page_ext; - struct stack_trace *trace; - - page_ext = lookup_page_ext(page); + struct page_ext *page_ext = lookup_page_ext(page); + struct stack_trace trace = { + .nr_entries = 0, + .max_entries = ARRAY_SIZE(page_ext->trace_entries), + .entries = &page_ext->trace_entries[0], + .skip = 3, + }; - trace = &page_ext->trace; - trace->nr_entries = 0; - trace->max_entries = ARRAY_SIZE(page_ext->trace_entries); - trace->entries = &page_ext->trace_entries[0]; - trace->skip = 3; - save_stack_trace(&page_ext->trace); + save_stack_trace(&trace); page_ext->order = order; page_ext->gfp_mask = gfp_mask; + page_ext->nr_entries = trace.nr_entries; __set_bit(PAGE_EXT_OWNER, &page_ext->flags); } @@ -84,6 +83,10 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, int ret; int pageblock_mt, page_mt; char *kbuf; + struct stack_trace trace = { + .nr_entries = page_ext->nr_entries, + .entries = &page_ext->trace_entries[0], + }; kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) @@ -121,8 +124,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, if (ret >= count) goto err; - ret += snprint_stack_trace(kbuf + ret, count - ret, - &page_ext->trace, 0); + ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0); if (ret >= count) goto err; |