Re: [PATCH 0/13] Parallel struct page initialisation v4

From: Mel Gorman
Date: Wed May 06 2015 - 08:05:30 EST


On Wed, May 06, 2015 at 11:22:20AM +0100, Mel Gorman wrote:
> On Wed, May 06, 2015 at 08:12:46AM +0100, Mel Gorman wrote:
> > On Tue, May 05, 2015 at 03:25:49PM -0700, Andrew Morton wrote:
> > > On Tue, 5 May 2015 23:13:29 +0100 Mel Gorman <mgorman@xxxxxxx> wrote:
> > >
> > > > > Alternatively, the page allocator can go off and synchronously
> > > > > initialize some pageframes itself. Keep doing that until the
> > > > > allocation attempt succeeds.
> > > > >
> > > >
> > > > That was rejected during review of earlier attempts at this feature on
> > > > the grounds that it impacted allocator fast paths.
> > >
> > > eh? Changes are only needed on the allocation-attempt-failed path,
> > > which is slow-path.
> >
> > We'd have to distinguish between falling back to other zones because the
> > high zone is artifically exhausted and normal ALLOC_BATCH exhaustion. We'd
> > also have to avoid falling back to remote nodes prematurely. While I have
> > not tried an implementation, I expected they would need to be in the fast
> > paths unless I used jump labels to get around it. I'm going to try altering
> > when we initialise instead so that it happens earlier.
> >
>
> Which looks as follows. Waiman, a test on the 24TB machine would be
> appreciated again. This patch should be applied instead of "mm: meminit:
> Take into account that large system caches scale linearly with memory"
>
> ---8<---
> mm: meminit: Finish initialisation of memory before basic setup
>

*sigh* Eventually build testing found the need for this

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1cef116727b6..052b9ba65b66 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -243,7 +243,7 @@ static inline void reset_deferred_meminit(pg_data_t *pgdat)
}

/* Returns true if the struct page for the pfn is uninitialised */
-static inline bool __init early_page_uninitialised(unsigned long pfn)
+static inline bool __meminit early_page_uninitialised(unsigned long pfn)
{
int nid = early_pfn_to_nid(pfn);

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