On 28.09.2015 14:03, Kirill A. Shutemov wrote:
On Mon, Sep 28, 2015 at 01:02:19PM +0300, Konstantin Khlebnikov wrote:
On 25.09.2015 22:13, Kirill A. Shutemov wrote:
On Fri, Sep 25, 2015 at 03:29:17PM +0300, Konstantin Khlebnikov wrote:
On 24.09.2015 17:50, Kirill A. Shutemov wrote:
This patch adds a third argument to macros which create function
definitions for page flags. This argument defines how page-flags helpers
behave on compound functions.
For now we define four policies:
- PF_ANY: the helper function operates on the page it gets, regardless
if it's non-compound, head or tail.
- PF_HEAD: the helper function operates on the head page of the compound
page if it gets tail page.
- PF_NO_TAIL: only head and non-compond pages are acceptable for this
helper function.
- PF_NO_COMPOUND: only non-compound pages are acceptable for this helper
function.
For now we use policy PF_ANY for all helpers, which matches current
behaviour.
We do not enforce the policy for TESTPAGEFLAG, because we have flags
checked for random pages all over the kernel. Noticeable exception to
this is PageTransHuge() which triggers VM_BUG_ON() for tail page.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 154 ++++++++++++++++++++++++++-------------------
1 file changed, 90 insertions(+), 64 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 713d3f2c2468..1b3babe5ff69 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -154,49 +154,68 @@ static inline int PageCompound(struct page *page)
return test_bit(PG_head, &page->flags) || PageTail(page);
}
+/* Page flags policies wrt compound pages */
+#define PF_ANY(page, enforce) page
+#define PF_HEAD(page, enforce) compound_head(page)
+#define PF_NO_TAIL(page, enforce) ({ \
+ if (enforce) \
+ VM_BUG_ON_PAGE(PageTail(page), page); \
+ else \
+ page = compound_head(page); \
+ page;})
+#define PF_NO_COMPOUND(page, enforce) ({ \
+ if (enforce) \
+ VM_BUG_ON_PAGE(PageCompound(page), page); \
Linux next-20150925 crashes here (at least in lkvm)
if CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
Hm. I don't see the crash in qemu. Could you share your config?
see in attachment
Still don't see it. Have you tried patch from my previous mail?
Just checked: patch fixes oops.
This part of 7e18adb4f80bea90d30b62158694d97c31f71d37
(mm: meminit: initialise remaining struct pages in parallel with kswapd)
is unclear:
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static void init_reserved_page(unsigned long pfn)
+{
+ pg_data_t *pgdat;
+ int nid, zid;
+
+ if (!early_page_uninitialised(pfn))
+ return;
+
+ nid = early_pfn_to_nid(pfn);
+ pgdat = NODE_DATA(nid);
+
+ for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+ struct zone *zone = &pgdat->node_zones[zid];
+
+ if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
+ break;
+ }
+ __init_single_pfn(pfn, zid, nid);
+}
+#else
+static inline void init_reserved_page(unsigned long pfn)
+{
+}
+#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
+
/*
* Initialised pages do not have PageReserved set. This function is
* called for each range allocated by the bootmem allocator and
* marks the pages PageReserved. The remaining valid pages are later
* sent to the buddy page allocator.
*/
-void reserve_bootmem_region(unsigned long start, unsigned long end)
+void __meminit reserve_bootmem_region(unsigned long start, unsigned
long end)
{
unsigned long start_pfn = PFN_DOWN(start);
unsigned long end_pfn = PFN_UP(end);
- for (; start_pfn < end_pfn; start_pfn++)
- if (pfn_valid(start_pfn))
- SetPageReserved(pfn_to_page(start_pfn));
+ for (; start_pfn < end_pfn; start_pfn++) {
+ if (pfn_valid(start_pfn)) {
+ struct page *page = pfn_to_page(start_pfn);
+
+ init_reserved_page(start_pfn);
+ SetPageReserved(page);
+ }
+ }
}
We leave struct page uninitialized but call SetPageReserved for it.
--
Konstantin
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