mm: cma: add functions to get region pages counters

PATCH In review Stefan Strogin 3 participants 4 messages Apr 3, 2015 – Apr 6, 2015

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Stefan Strogin

author

2015-04-03 12:42 UTC #0 lore raw

PATCH 1/1 mm: cma: add functions to get region pages counters

From: Dmitry Safonov <[email protected]>

Here are two functions that provide interface to compute/get used size and size of biggest free chunk in cma region. Add that information to debugfs.

Signed-off-by Dmitry Safonov <[email protected]>

Signed-off-by Stefan Strogin <[email protected]>

Acked-by Michal Nazarewicz <[email protected]>

---

Took out from the patch set "mm: cma: add some debug information for CMA" v4
(http://thread.gmane.org/gmane.linux.kernel.mm/129903) because of probable uselessness of the most part of the set.

 include/linux/cma.h |  2 ++
 mm/cma.c            | 30 ++++++++++++++++++++++++++++++
 mm/cma_debug.c      | 24 ++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

include/linux/cma.h +2 -0

index f7ef093..1231f50 100644
@@ -18,6 +18,8 @@ struct cma;
 extern unsigned long totalcma_pages;
 extern phys_addr_t cma_get_base(const struct cma *cma);
 extern unsigned long cma_get_size(const struct cma *cma);
+extern unsigned long cma_get_used(struct cma *cma);
+extern unsigned long cma_get_maxchunk(struct cma *cma);
 
 extern int __init cma_declare_contiguous(phys_addr_t base,
 			phys_addr_t size, phys_addr_t limit,

mm/cma.c +30 -0

index 3a7a67b..d839011 100644
@@ -53,6 +53,36 @@ unsigned long cma_get_size(const struct cma *cma)
 	return cma->count << PAGE_SHIFT;
 }
 
+unsigned long cma_get_used(struct cma *cma)
+{
+	unsigned long ret = 0;
+
+	mutex_lock(&cma->lock);
+	/* pages counter is smaller than sizeof(int) */
+	ret = bitmap_weight(cma->bitmap, (int)cma->count);
+	mutex_unlock(&cma->lock);
+
+	return ret << cma->order_per_bit;
+}
+
+unsigned long cma_get_maxchunk(struct cma *cma)
+{
+	unsigned long maxchunk = 0;
+	unsigned long start, end = 0;
+
+	mutex_lock(&cma->lock);
+	for (;;) {
+		start = find_next_zero_bit(cma->bitmap, cma->count, end);
+		if (start >= cma->count)
+			break;
+		end = find_next_bit(cma->bitmap, cma->count, start);
+		maxchunk = max(end - start, maxchunk);
+	}
+	mutex_unlock(&cma->lock);
+
+	return maxchunk << cma->order_per_bit;
+}
+
 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
 					     int align_order)
 {

mm/cma_debug.c +24 -0

index ec915e6..984cedd 100644
@@ -33,6 +33,28 @@ static int cma_debugfs_get(void *data, u64 *val)
 
 DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
 
+static int cma_used_get(void *data, u64 *val)
+{
+	struct cma *cma = data;
+
+	*val = cma_get_used(cma);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
+
+static int cma_maxchunk_get(void *data, u64 *val)
+{
+	struct cma *cma = data;
+
+	*val = cma_get_maxchunk(cma);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
+
 static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
 {
 	spin_lock(&cma->mem_head_lock);

@@ -149,6 +171,8 @@ static void cma_debugfs_add_one(struct cma *cma, int idx)
 				&cma->count, &cma_debugfs_fops);
 	debugfs_create_file("order_per_bit", S_IRUGO, tmp,
 				&cma->order_per_bit, &cma_debugfs_fops);
+	debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
+	debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
 
 	u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
 	debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);

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Andrew Morton

maintainer

2015-04-03 21:58 UTC #1 lore raw

Quoted 32 lines · On Fri, 03 Apr 2015 15:42:40 +0300 Stefan Strogin <[email protected]>…

From: Dmitry Safonov <[email protected]>

Here are two functions that provide interface to compute/get used size and size of biggest free chunk in cma region. Add that information to debugfs.

...

mm/cma.c +19 -0

@@ -53,6 +53,36 @@ unsigned long cma_get_size(const struct cma *cma)
 	return cma->count << PAGE_SHIFT;
 }
 
+unsigned long cma_get_used(struct cma *cma)
+{
+	unsigned long ret = 0;
+
+	mutex_lock(&cma->lock);
+	/* pages counter is smaller than sizeof(int) */
+	ret = bitmap_weight(cma->bitmap, (int)cma->count);
+	mutex_unlock(&cma->lock);
+
+	return ret << cma->order_per_bit;
+}
+
+unsigned long cma_get_maxchunk(struct cma *cma)
+{
+	unsigned long maxchunk = 0;
+	unsigned long start, end = 0;
+
+	mutex_lock(&cma->lock);
+	for (;;) {

mm/cma.c unsigned long cma_get_size(const struct cma *cma) · line 84

Quoted 10 lines

mm/cma.c +10 -0

+		start = find_next_zero_bit(cma->bitmap, cma->count, end);
+		if (start >= cma->count)
+			break;
+		end = find_next_bit(cma->bitmap, cma->count, start);
+		maxchunk = max(end - start, maxchunk);
+	}
+	mutex_unlock(&cma->lock);
+
+	return maxchunk << cma->order_per_bit;
+}

This will cause unused code to be included in cma.o when CONFIG_CMA_DEBUGFS=n. Please review the below patch which moves it all into cma_debug.c

Quoted 4 lines

mm/cma_debug.c +0 -0

@@ -33,6 +33,28 @@ static int cma_debugfs_get(void *data, u64 *val)

mm/cma_debug.c static int cma_debugfs_get(void *data, u64 *val) · line 43

Quoted 10 lines

mm/cma_debug.c +8 -0

 DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
 
+static int cma_used_get(void *data, u64 *val)
+{
+	struct cma *cma = data;
+
+	*val = cma_get_used(cma);
+
+	return 0;
+}

We have cma_used_get() and cma_get_used(). Confusing! Can we think of better names for one or both of them?

From: Andrew Morton <[email protected]>
Subject: mm-cma-add-functions-to-get-region-pages-counters-fix

move debug code from cma.c into cma_debug.c so it doesn't get included in CONFIG_CMA_DEBUGFS=n builds

Cc Dmitry Safonov <[email protected]>

Cc Michal Nazarewicz <[email protected]>

Cc Stefan Strogin <[email protected]>

Cc Marek Szyprowski <[email protected]>

Cc Joonsoo Kim <[email protected]>

Cc Pintu Kumar <[email protected]>

Cc Weijie Yang <[email protected]>

Cc Laurent Pinchart <[email protected]>

Cc Vyacheslav Tyrtov <[email protected]>

Cc Aleksei Mateosian <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

---

 include/linux/cma.h |    2 --
 mm/cma.c            |   30 ------------------------------
 mm/cma_debug.c      |   31 +++++++++++++++++++++++++++++++
 3 files changed, 31 insertions(+), 32 deletions(-)

include/linux/cma.h renamed from include/linux/cma.h~mm-cma-add-functions-to-get-region-pages-counters-fix +0 -2

diff -puN include/linux/cma.h~mm-cma-add-functions-to-get-region-pages-counters-fix include/linux/cma.h
@@ -18,8 +18,6 @@ struct cma;
 extern unsigned long totalcma_pages;
 extern phys_addr_t cma_get_base(const struct cma *cma);
 extern unsigned long cma_get_size(const struct cma *cma);
-extern unsigned long cma_get_used(struct cma *cma);
-extern unsigned long cma_get_maxchunk(struct cma *cma);
 
 extern int __init cma_declare_contiguous(phys_addr_t base,
 			phys_addr_t size, phys_addr_t limit,

mm/cma.c renamed from mm/cma.c~mm-cma-add-functions-to-get-region-pages-counters-fix +0 ~~-30~~

diff -puN mm/cma.c~mm-cma-add-functions-to-get-region-pages-counters-fix mm/cma.c
@@ -53,36 +53,6 @@ unsigned long cma_get_size(const struct
 	return cma->count << PAGE_SHIFT;
 }
 
-unsigned long cma_get_used(struct cma *cma)
-{
-	unsigned long ret = 0;
-
-	mutex_lock(&cma->lock);
-	/* pages counter is smaller than sizeof(int) */
-	ret = bitmap_weight(cma->bitmap, (int)cma->count);
-	mutex_unlock(&cma->lock);
-
-	return ret << cma->order_per_bit;
-}
-
-unsigned long cma_get_maxchunk(struct cma *cma)
-{
-	unsigned long maxchunk = 0;
-	unsigned long start, end = 0;
-
-	mutex_lock(&cma->lock);
-	for (;;) {
-		start = find_next_zero_bit(cma->bitmap, cma->count, end);
-		if (start >= cma->count)
-			break;
-		end = find_next_bit(cma->bitmap, cma->count, start);
-		maxchunk = max(end - start, maxchunk);
-	}
-	mutex_unlock(&cma->lock);
-
-	return maxchunk << cma->order_per_bit;
-}
-
 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
 					     int align_order)
 {

mm/cma_debug.c renamed from mm/cma_debug.c~mm-cma-add-functions-to-get-region-pages-counters-fix +31 -0

diff -puN mm/cma_debug.c~mm-cma-add-functions-to-get-region-pages-counters-fix mm/cma_debug.c
@@ -22,6 +22,37 @@ struct cma_mem {
 
 static struct dentry *cma_debugfs_root;
 
+static unsigned long cma_get_used(struct cma *cma)
+{
+	unsigned long ret = 0;
+
+	mutex_lock(&cma->lock);
+	/* pages counter is smaller than sizeof(int) */
+	ret = bitmap_weight(cma->bitmap, (int)cma->count);
+	mutex_unlock(&cma->lock);
+
+	return ret << cma->order_per_bit;
+}
+
+static unsigned long cma_get_maxchunk(struct cma *cma)
+{
+	unsigned long maxchunk = 0;
+	unsigned long start, end = 0;
+
+	mutex_lock(&cma->lock);
+	for (;;) {
+		start = find_next_zero_bit(cma->bitmap, cma->count, end);
+		if (start >= cma->count)
+			break;
+		end = find_next_bit(cma->bitmap, cma->count, start);
+		maxchunk = max(end - start, maxchunk);
+	}
+	mutex_unlock(&cma->lock);
+
+	return maxchunk << cma->order_per_bit;
+}
+
+
 static int cma_debugfs_get(void *data, u64 *val)
 {
 	unsigned long *p = data;

Stefan Strogin

2015-04-06 21:30 UTC #2 lore raw

Hello Andrew,

Quoted 40 lines · Andrew Morton

Quoted 38 lines · On Fri, 03 Apr 2015 15:42:40 +0300 Stefan Strogin <[email protected]>…

From: Dmitry Safonov <[email protected]>

Here are two functions that provide interface to compute/get used size and size of biggest free chunk in cma region. Add that information to debugfs.

...

mm/cma.c +25 -0

@@ -53,6 +53,36 @@ unsigned long cma_get_size(const struct cma *cma)
 	return cma->count << PAGE_SHIFT;
 }
 
+unsigned long cma_get_used(struct cma *cma)
+{
+	unsigned long ret = 0;
+
+	mutex_lock(&cma->lock);
+	/* pages counter is smaller than sizeof(int) */
+	ret = bitmap_weight(cma->bitmap, (int)cma->count);
+	mutex_unlock(&cma->lock);
+
+	return ret << cma->order_per_bit;
+}
+
+unsigned long cma_get_maxchunk(struct cma *cma)
+{
+	unsigned long maxchunk = 0;
+	unsigned long start, end = 0;
+
+	mutex_lock(&cma->lock);
+	for (;;) {
+		start = find_next_zero_bit(cma->bitmap, cma->count, end);
+		if (start >= cma->count)
+			break;
+		end = find_next_bit(cma->bitmap, cma->count, start);
+		maxchunk = max(end - start, maxchunk);
+	}

Quoted 9 lines

mm/cma.c unsigned long cma_get_size(const struct cma *cma) · line 84
Quoted 4 lines
mm/cma.c +4 -0
+	mutex_unlock(&cma->lock);
+
+	return maxchunk << cma->order_per_bit;
+}
This will cause unused code to be included in cma.o when CONFIG_CMA_DEBUGFS=n. Please review the below patch which moves it all into cma_debug.c

Thank you very much for the reply and for the patches.

Quoted 6 lines

mm/cma_debug.c +0 -0

@@ -33,6 +33,28 @@ static int cma_debugfs_get(void *data, u64 *val)
 
 DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");

Quoted 12 lines

mm/cma_debug.c struct cma_mem { · line 35
Quoted 8 lines
mm/cma_debug.c +8 -0
+static int cma_used_get(void *data, u64 *val)
+{
+	struct cma *cma = data;
+
+	*val = cma_get_used(cma);
+
+	return 0;
+}
We have cma_used_get() and cma_get_used(). Confusing! Can we think of better names for one or both of them?

Oh. Excuse me for the bad code.
Wouldn't it be better to merge cma_get_used() and cma_get_maxchunk() into cma_*_get() as they aren't used anywhere else? Please see the following patch.

Stefan Strogin

author

2015-04-06 21:32 UTC #3 lore raw

PATCH 1/1 mm-cma-add-functions-to-get-region-pages-counters-fix-2

Move the code from cma_get_used() and cma_get_maxchunk() to cma_used_get() and cma_maxchunk_get(), because cma_get_*() aren't used anywhere else, and because of their confusing similar names.

Signed-off-by Stefan Strogin <[email protected]>

---
 mm/cma_debug.c | 51 ++++++++++++++++++---------------------------------
 1 file changed, 18 insertions(+), 33 deletions(-)

mm/cma_debug.c +18 ~~-33~~

index 56c4175..abb9d0b 100644
@@ -22,37 +22,6 @@ struct cma_mem {
 
 static struct dentry *cma_debugfs_root;
 
-static unsigned long cma_get_used(struct cma *cma)
-{
-	unsigned long ret = 0;
-
-	mutex_lock(&cma->lock);
-	/* pages counter is smaller than sizeof(int) */
-	ret = bitmap_weight(cma->bitmap, (int)cma->count);
-	mutex_unlock(&cma->lock);
-
-	return ret << cma->order_per_bit;
-}
-
-static unsigned long cma_get_maxchunk(struct cma *cma)
-{
-	unsigned long maxchunk = 0;
-	unsigned long start, end = 0;
-
-	mutex_lock(&cma->lock);
-	for (;;) {
-		start = find_next_zero_bit(cma->bitmap, cma->count, end);
-		if (start >= cma->count)
-			break;
-		end = find_next_bit(cma->bitmap, cma->count, start);
-		maxchunk = max(end - start, maxchunk);
-	}
-	mutex_unlock(&cma->lock);
-
-	return maxchunk << cma->order_per_bit;
-}
-
-
 static int cma_debugfs_get(void *data, u64 *val)
 {
 	unsigned long *p = data;

@@ -66,8 +35,13 @@ DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
 static int cma_used_get(void *data, u64 *val)
 {
 	struct cma *cma = data;
+	unsigned long used;
 
-	*val = cma_get_used(cma);
+	mutex_lock(&cma->lock);
+	/* pages counter is smaller than sizeof(int) */
+	used = bitmap_weight(cma->bitmap, (int)cma->count);
+	mutex_unlock(&cma->lock);
+	*val = used << cma->order_per_bit;
 
 	return 0;
 }

@@ -76,8 +50,19 @@ DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
 static int cma_maxchunk_get(void *data, u64 *val)
 {
 	struct cma *cma = data;
+	unsigned long maxchunk = 0;
+	unsigned long start, end = 0;
 
-	*val = cma_get_maxchunk(cma);
+	mutex_lock(&cma->lock);
+	for (;;) {
+		start = find_next_zero_bit(cma->bitmap, cma->count, end);
+		if (start >= cma->count)
+			break;
+		end = find_next_bit(cma->bitmap, cma->count, start);
+		maxchunk = max(end - start, maxchunk);
+	}
+	mutex_unlock(&cma->lock);
+	*val = maxchunk << cma->order_per_bit;
 
 	return 0;
 }

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