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Groups > linux.kernel > #1234064
| From | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages |
| Date | 2015-09-28 13:50 +0200 |
| Message-ID | <qdF6p-4DC-17@gated-at.bofh.it> (permalink) |
| References | (2 earlier) <qcga8-6cP-57@gated-at.bofh.it> <qcAiv-1fs-19@gated-at.bofh.it> <qcGHg-27F-3@gated-at.bofh.it> <qdDxE-2zm-17@gated-at.bofh.it> <qdEtI-3Uu-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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@linux.intel.com>
>>>>> ---
>>>>> 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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[PATCH 00/16] Refreshed page-flags patchset "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
[PATCH 12/16] page-flags: define PG_mlocked behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
[PATCH 03/16] page-flags: introduce page flags policies wrt compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2015-09-25 14:30 +0200
Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-25 21:20 +0200
Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-28 13:10 +0200
Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages Konstantin Khlebnikov <khlebnikov@yandex-team.ru> - 2015-09-28 13:50 +0200
Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-28 20:00 +0200
[PATCH 04/16] page-flags: define PG_locked behavior on compound pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-09-24 17:00 +0200
Re: [PATCH 04/16] page-flags: define PG_locked behavior on compound pages Christoph Lameter <cl@linux.com> - 2015-09-24 18:10 +0200
Re: [PATCH 04/16] page-flags: define PG_locked behavior on compound pages "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-24 22:30 +0200
Re: [PATCH 00/16] Refreshed page-flags patchset Christoph Lameter <cl@linux.com> - 2015-09-24 18:20 +0200
Re: [PATCH 00/16] Refreshed page-flags patchset "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-09-24 22:30 +0200
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