linux-kernel - Re: [PATCH] mm, x86: Do not zero hugetlbfs pages at boot. -v2

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Message-ID: <20130403172132.GZ29151@sgi.com>
Date:	Wed, 3 Apr 2013 12:21:32 -0500
From:	Robin Holt <holt@....com>
To:	Michal Hocko <mhocko@...e.cz>
Cc:	Robin Holt <holt@....com>, Cliff Wickman <cpw@....com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, x86@...nel.org,
	wli@...omorphy.com
Subject: Re: [PATCH] mm, x86: Do not zero hugetlbfs pages at boot. -v2

On Wed, Apr 03, 2013 at 04:00:49PM +0200, Michal Hocko wrote:
> On Tue 02-04-13 21:43:44, Robin Holt wrote:
> [...]
> > diff --git a/mm/bootmem.c b/mm/bootmem.c
> > index 2b0bcb0..b2e4027 100644
> > --- a/mm/bootmem.c
> > +++ b/mm/bootmem.c
> > @@ -705,12 +705,16 @@ void * __init __alloc_bootmem(unsigned long size, unsigned long align,
> >  
> >  void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
> >  				unsigned long size, unsigned long align,
> > -				unsigned long goal, unsigned long limit)
> > +				unsigned long goal, unsigned long limit,
> > +				int zeroed)
> >  {
> >  	void *ptr;
> >  
> >  	if (WARN_ON_ONCE(slab_is_available()))
> > -		return kzalloc(size, GFP_NOWAIT);
> > +		if (zeroed)
> > +			return kzalloc(size, GFP_NOWAIT);
> > +		else
> > +			return kmalloc(size, GFP_NOWAIT);
> >  again:
> >  
> >  	/* do not panic in alloc_bootmem_bdata() */
> 
> You need to update alloc_bootmem_bdata and alloc_bootmem_core as well.
> Otherwise this is a no-op for early allocations when slab is not
> available which is the case unless something is broken.

Michal,

Does this do what you would expect?  I compiled this for ia64, but I
have not tested it at all.

Robin

---
 mm/bootmem.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/mm/bootmem.c b/mm/bootmem.c
index b2e4027..350e0ab 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -497,7 +497,8 @@ static unsigned long __init align_off(struct bootmem_data *bdata,
 
 static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata,
 					unsigned long size, unsigned long align,
-					unsigned long goal, unsigned long limit)
+					unsigned long goal, unsigned long limit,
+					int zeroed)
 {
 	unsigned long fallback = 0;
 	unsigned long min, max, start, sidx, midx, step;
@@ -584,7 +585,8 @@ find_block:
 
 		region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
 				start_off);
-		memset(region, 0, size);
+		if (zeroed)
+			memset(region, 0, size);
 		/*
 		 * The min_count is set to 0 so that bootmem allocated blocks
 		 * are never reported as leaks.
@@ -605,13 +607,18 @@ find_block:
 static void * __init alloc_bootmem_core(unsigned long size,
 					unsigned long align,
 					unsigned long goal,
-					unsigned long limit)
+					unsigned long limit,
+					int zeroed)
 {
 	bootmem_data_t *bdata;
 	void *region;
 
-	if (WARN_ON_ONCE(slab_is_available()))
-		return kzalloc(size, GFP_NOWAIT);
+	if (WARN_ON_ONCE(slab_is_available())) {
+		if (zeroed)
+			return kzalloc(size, GFP_NOWAIT);
+		else
+			return kmalloc(size, GFP_NOWAIT);
+	}
 
 	list_for_each_entry(bdata, &bdata_list, list) {
 		if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
@@ -619,7 +626,7 @@ static void * __init alloc_bootmem_core(unsigned long size,
 		if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
 			break;
 
-		region = alloc_bootmem_bdata(bdata, size, align, goal, limit);
+		region = alloc_bootmem_bdata(bdata, size, align, goal, limit, zeroed);
 		if (region)
 			return region;
 	}
@@ -635,7 +642,7 @@ static void * __init ___alloc_bootmem_nopanic(unsigned long size,
 	void *ptr;
 
 restart:
-	ptr = alloc_bootmem_core(size, align, goal, limit);
+	ptr = alloc_bootmem_core(size, align, goal, limit, 1);
 	if (ptr)
 		return ptr;
 	if (goal) {
@@ -710,22 +717,23 @@ void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
 {
 	void *ptr;
 
-	if (WARN_ON_ONCE(slab_is_available()))
+	if (WARN_ON_ONCE(slab_is_available())) {
 		if (zeroed)
 			return kzalloc(size, GFP_NOWAIT);
 		else
 			return kmalloc(size, GFP_NOWAIT);
+	}
 again:
 
 	/* do not panic in alloc_bootmem_bdata() */
 	if (limit && goal + size > limit)
 		limit = 0;
 
-	ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
+	ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit, zeroed);
 	if (ptr)
 		return ptr;
 
-	ptr = alloc_bootmem_core(size, align, goal, limit);
+	ptr = alloc_bootmem_core(size, align, goal, limit, zeroed);
 	if (ptr)
 		return ptr;
 
@@ -813,7 +821,7 @@ void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
 
 		new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
 		ptr = alloc_bootmem_bdata(pgdat->bdata, size, align,
-						 new_goal, 0);
+						 new_goal, 0, 1);
 		if (ptr)
 			return ptr;
 	}
-- 
1.8.1.2

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