[PATCH v2 0/5] follow-up "Optimize CONFIG_DEBUG_PAGEALLOC"

[PATCH v2 0/5] follow-up "Optimize CONFIG_DEBUG_PAGEALLOC"

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

v2) Changes
o fix powerpc build failure (basic build test done)
o export symbol for module build
o change comment and clean up code

As CONFIG_DEBUG_PAGEALLOC can be enabled/disabled via kernel
parameters we can optimize some cases by checking the enablement
state.

This is follow-up work for Christian's Optimize CONFIG_DEBUG_PAGEALLOC.

https://lkml.org/lkml/2016/1/27/194

I can't test patches for sound, power and tile,
so please review them, maintainers. :)

Remaining work is to make sparc to be aware of this but it looks
not easy for me so I skip that in this series.

It would be the best that these paches are routed through Andrew's tree,
because there is a dependency to MM.

Andrew, there is mis-spelled word (compliled -> compiled) in commit
description so I re-send all. Except powerpc one, others are basically
same with the patches on your tree.

Thanks.

Joonsoo Kim (5):
  mm/vmalloc: query dynamic DEBUG_PAGEALLOC setting
  mm/slub: query dynamic DEBUG_PAGEALLOC setting
  sound: query dynamic DEBUG_PAGEALLOC setting
  powerpc: query dynamic DEBUG_PAGEALLOC setting
  tile: query dynamic DEBUG_PAGEALLOC setting

 arch/powerpc/kernel/traps.c     |  5 ++---
 arch/powerpc/mm/hash_utils_64.c | 36 ++++++++++++++++++++----------------
 arch/powerpc/mm/init_32.c       |  8 ++++----
 arch/tile/mm/init.c             | 11 +++++++----
 mm/page_alloc.c                 |  1 +
 mm/slub.c                       |  7 +++----
 mm/vmalloc.c                    | 25 ++++++++++++-------------
 sound/drivers/pcsp/pcsp.c       |  9 +++++----
 8 files changed, 54 insertions(+), 48 deletions(-)

-- 
1.9.1

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[PATCH v2 1/5] mm/vmalloc: query dynamic DEBUG_PAGEALLOC setting

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

We can disable debug_pagealloc processing even if the code is compiled
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

v2: update comment, per David.
adjust comment to use 80 cols, per Andrew.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/vmalloc.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index fb42a5b..d4b2e34 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -531,22 +531,21 @@ static void unmap_vmap_area(struct vmap_area *va)
 static void vmap_debug_free_range(unsigned long start, unsigned long end)
 {
 	/*
-	 * Unmap page tables and force a TLB flush immediately if
-	 * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free
-	 * bugs similarly to those in linear kernel virtual address
-	 * space after a page has been freed.
+	 * Unmap page tables and force a TLB flush immediately if pagealloc
+	 * debugging is enabled.  This catches use after free bugs similarly to
+	 * those in linear kernel virtual address space after a page has been
+	 * freed.
 	 *
-	 * All the lazy freeing logic is still retained, in order to
-	 * minimise intrusiveness of this debugging feature.
+	 * All the lazy freeing logic is still retained, in order to minimise
+	 * intrusiveness of this debugging feature.
 	 *
-	 * This is going to be *slow* (linear kernel virtual address
-	 * debugging doesn't do a broadcast TLB flush so it is a lot
-	 * faster).
+	 * This is going to be *slow* (linear kernel virtual address debugging
+	 * doesn't do a broadcast TLB flush so it is a lot faster).
 	 */
-#ifdef CONFIG_DEBUG_PAGEALLOC
-	vunmap_page_range(start, end);
-	flush_tlb_kernel_range(start, end);
-#endif
+	if (debug_pagealloc_enabled()) {
+		vunmap_page_range(start, end);
+		flush_tlb_kernel_range(start, end);
+	}
 }
 
 /*
-- 
1.9.1

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[PATCH v2 2/5] mm/slub: query dynamic DEBUG_PAGEALLOC setting

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

We can disable debug_pagealloc processing even if the code is compiled
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

v2: clean up code, per Christian.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/slub.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 606488b..a1874c2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -250,11 +250,10 @@ static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 {
 	void *p;
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
+	if (!debug_pagealloc_enabled())
+		return get_freepointer(s, object);
+
 	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
-#else
-	p = get_freepointer(s, object);
-#endif
 	return p;
 }
 
-- 
1.9.1

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Re: [PATCH v2 2/5] mm/slub: query dynamic DEBUG_PAGEALLOC setting

[Christian Borntraeger]

On 02/11/2016 05:04 AM, js1304@gmail.com wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> We can disable debug_pagealloc processing even if the code is compiled
> with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
> whether it is enabled or not in runtime.
> 
> v2: clean up code, per Christian.
> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

> ---
>  mm/slub.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 606488b..a1874c2 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -250,11 +250,10 @@ static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
>  {
>  	void *p;
> 
> -#ifdef CONFIG_DEBUG_PAGEALLOC
> +	if (!debug_pagealloc_enabled())
> +		return get_freepointer(s, object);
> +
>  	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
> -#else
> -	p = get_freepointer(s, object);
> -#endif
>  	return p;
>  }
> 

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[PATCH v2 3/5] sound: query dynamic DEBUG_PAGEALLOC setting

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

We can disable debug_pagealloc processing even if the code is compiled
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

v2: export _debug_pagealloc_enabled to modules, per Andrew.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 mm/page_alloc.c           | 1 +
 sound/drivers/pcsp/pcsp.c | 9 +++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 87b3e2f..00118fe 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -498,6 +498,7 @@ void prep_compound_page(struct page *page, unsigned int order)
 unsigned int _debug_guardpage_minorder;
 bool _debug_pagealloc_enabled __read_mostly
 			= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
+EXPORT_SYMBOL(_debug_pagealloc_enabled);
 bool _debug_guardpage_enabled __read_mostly;
 
 static int __init early_debug_pagealloc(char *buf)
diff --git a/sound/drivers/pcsp/pcsp.c b/sound/drivers/pcsp/pcsp.c
index 27e25bb..72e2d00 100644
--- a/sound/drivers/pcsp/pcsp.c
+++ b/sound/drivers/pcsp/pcsp.c
@@ -14,6 +14,7 @@
 #include <linux/input.h>
 #include <linux/delay.h>
 #include <linux/bitops.h>
+#include <linux/mm.h>
 #include "pcsp_input.h"
 #include "pcsp.h"
 
@@ -148,11 +149,11 @@ static int alsa_card_pcsp_init(struct device *dev)
 		return err;
 	}
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
 	/* Well, CONFIG_DEBUG_PAGEALLOC makes the sound horrible. Lets alert */
-	printk(KERN_WARNING "PCSP: CONFIG_DEBUG_PAGEALLOC is enabled, "
-	       "which may make the sound noisy.\n");
-#endif
+	if (debug_pagealloc_enabled()) {
+		printk(KERN_WARNING "PCSP: CONFIG_DEBUG_PAGEALLOC is enabled, "
+		       "which may make the sound noisy.\n");
+	}
 
 	return 0;
 }
-- 
1.9.1

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[PATCH v2 4/5] powerpc: query dynamic DEBUG_PAGEALLOC setting

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

We can disable debug_pagealloc processing even if the code is compiled
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

v2: fix build failure

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 arch/powerpc/kernel/traps.c     |  5 ++---
 arch/powerpc/mm/hash_utils_64.c | 36 ++++++++++++++++++++----------------
 arch/powerpc/mm/init_32.c       |  8 ++++----
 3 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index b6becc7..33c47fc 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -203,9 +203,8 @@ static int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 #ifdef CONFIG_SMP
 	printk("SMP NR_CPUS=%d ", NR_CPUS);
 #endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
-	printk("DEBUG_PAGEALLOC ");
-#endif
+	if (debug_pagealloc_enabled())
+		printk("DEBUG_PAGEALLOC ");
 #ifdef CONFIG_NUMA
 	printk("NUMA ");
 #endif
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index ba59d59..1005281 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -255,8 +255,10 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 
 		if (ret < 0)
 			break;
+
 #ifdef CONFIG_DEBUG_PAGEALLOC
-		if ((paddr >> PAGE_SHIFT) < linear_map_hash_count)
+		if (debug_pagealloc_enabled() &&
+			(paddr >> PAGE_SHIFT) < linear_map_hash_count)
 			linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
 #endif /* CONFIG_DEBUG_PAGEALLOC */
 	}
@@ -512,17 +514,17 @@ static void __init htab_init_page_sizes(void)
 	if (mmu_has_feature(MMU_FTR_16M_PAGE))
 		memcpy(mmu_psize_defs, mmu_psize_defaults_gp,
 		       sizeof(mmu_psize_defaults_gp));
- found:
-#ifndef CONFIG_DEBUG_PAGEALLOC
-	/*
-	 * Pick a size for the linear mapping. Currently, we only support
-	 * 16M, 1M and 4K which is the default
-	 */
-	if (mmu_psize_defs[MMU_PAGE_16M].shift)
-		mmu_linear_psize = MMU_PAGE_16M;
-	else if (mmu_psize_defs[MMU_PAGE_1M].shift)
-		mmu_linear_psize = MMU_PAGE_1M;
-#endif /* CONFIG_DEBUG_PAGEALLOC */
+found:
+	if (!debug_pagealloc_enabled()) {
+		/*
+		 * Pick a size for the linear mapping. Currently, we only
+		 * support 16M, 1M and 4K which is the default
+		 */
+		if (mmu_psize_defs[MMU_PAGE_16M].shift)
+			mmu_linear_psize = MMU_PAGE_16M;
+		else if (mmu_psize_defs[MMU_PAGE_1M].shift)
+			mmu_linear_psize = MMU_PAGE_1M;
+	}
 
 #ifdef CONFIG_PPC_64K_PAGES
 	/*
@@ -721,10 +723,12 @@ static void __init htab_initialize(void)
 	prot = pgprot_val(PAGE_KERNEL);
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
-	linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
-	linear_map_hash_slots = __va(memblock_alloc_base(linear_map_hash_count,
-						    1, ppc64_rma_size));
-	memset(linear_map_hash_slots, 0, linear_map_hash_count);
+	if (debug_pagealloc_enabled()) {
+		linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
+		linear_map_hash_slots = __va(memblock_alloc_base(
+				linear_map_hash_count, 1, ppc64_rma_size));
+		memset(linear_map_hash_slots, 0, linear_map_hash_count);
+	}
 #endif /* CONFIG_DEBUG_PAGEALLOC */
 
 	/* On U3 based machines, we need to reserve the DART area and
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index a10be66..c2b7716 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -112,10 +112,10 @@ void __init MMU_setup(void)
 	if (strstr(boot_command_line, "noltlbs")) {
 		__map_without_ltlbs = 1;
 	}
-#ifdef CONFIG_DEBUG_PAGEALLOC
-	__map_without_bats = 1;
-	__map_without_ltlbs = 1;
-#endif
+	if (debug_pagealloc_enabled()) {
+		__map_without_bats = 1;
+		__map_without_ltlbs = 1;
+	}
 }
 
 /*
-- 
1.9.1

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[PATCH v2 5/5] tile: query dynamic DEBUG_PAGEALLOC setting

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

We can disable debug_pagealloc processing even if the code is compiled
with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query
whether it is enabled or not in runtime.

Acked-by: Chris Metcalf <cmetcalf@ezchip.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 arch/tile/mm/init.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index d4e1fc4..a0582b7 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -896,17 +896,15 @@ void __init pgtable_cache_init(void)
 		panic("pgtable_cache_init(): Cannot create pgd cache");
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
-static long __write_once initfree;
-#else
 static long __write_once initfree = 1;
-#endif
+static bool __write_once set_initfree_done;
 
 /* Select whether to free (1) or mark unusable (0) the __init pages. */
 static int __init set_initfree(char *str)
 {
 	long val;
 	if (kstrtol(str, 0, &val) == 0) {
+		set_initfree_done = true;
 		initfree = val;
 		pr_info("initfree: %s free init pages\n",
 			initfree ? "will" : "won't");
@@ -919,6 +917,11 @@ static void free_init_pages(char *what, unsigned long begin, unsigned long end)
 {
 	unsigned long addr = (unsigned long) begin;
 
+	/* Prefer user request first */
+	if (!set_initfree_done) {
+		if (debug_pagealloc_enabled())
+			initfree = 0;
+	}
 	if (kdata_huge && !initfree) {
 		pr_warn("Warning: ignoring initfree=0: incompatible with kdata=huge\n");
 		initfree = 1;
-- 
1.9.1

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