Re: [PATCH 3/3] CMA: Add cma_alloc_counter to make cma_alloc work better if it meet busy range
On Thu, Dec 25, 2014 at 05:43:28PM +0800, Hui Zhu wrote: > In [1], Joonsoo said that cma_alloc_counter is useless because pageblock > is isolated. > But if alloc_contig_range meet a busy range, it will undo_isolate_page_range > before goto try next range. At this time, __rmqueue_cma can begin allocd > CMA memory from the range. Is there any real issue from this? When failed, we will quickly re-isolate pageblock for adjacent page so there is no big problem I guess. If there is real issue, how about doing start_isolation/undo_isolation in cma_alloc()? It would reduce useless do/undo isolation due to failed trial. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3/3] CMA: Add cma_alloc_counter to make cma_alloc work better if it meet busy range
On Thu, Dec 25, 2014 at 05:43:28PM +0800, Hui Zhu wrote: In [1], Joonsoo said that cma_alloc_counter is useless because pageblock is isolated. But if alloc_contig_range meet a busy range, it will undo_isolate_page_range before goto try next range. At this time, __rmqueue_cma can begin allocd CMA memory from the range. Is there any real issue from this? When failed, we will quickly re-isolate pageblock for adjacent page so there is no big problem I guess. If there is real issue, how about doing start_isolation/undo_isolation in cma_alloc()? It would reduce useless do/undo isolation due to failed trial. Thanks. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3/3] CMA: Add cma_alloc_counter to make cma_alloc work better if it meet busy range
In [1], Joonsoo said that cma_alloc_counter is useless because pageblock
is isolated.
But if alloc_contig_range meet a busy range, it will undo_isolate_page_range
before goto try next range. At this time, __rmqueue_cma can begin allocd
CMA memory from the range.
So I add cma_alloc_counter let __rmqueue doesn't call __rmqueue_cma when
cma_alloc works.
[1] https://lkml.org/lkml/2014/10/24/26
Signed-off-by: Hui Zhu
---
include/linux/cma.h | 2 ++
mm/cma.c| 6 ++
mm/page_alloc.c | 8 +++-
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9384ba6..155158f 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -26,6 +26,8 @@ extern int __init cma_declare_contiguous(phys_addr_t base,
extern int cma_init_reserved_mem(phys_addr_t base,
phys_addr_t size, int order_per_bit,
struct cma **res_cma);
+
+extern atomic_t cma_alloc_counter;
extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
extern bool cma_release(struct cma *cma, struct page *pages, int count);
#endif
diff --git a/mm/cma.c b/mm/cma.c
index 6707b5d..b63f6be 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -348,6 +348,8 @@ err:
return ret;
}
+atomic_t cma_alloc_counter = ATOMIC_INIT(0);
+
/**
* cma_alloc() - allocate pages from contiguous area
* @cma: Contiguous memory region for which the allocation is performed.
@@ -378,6 +380,8 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned
int align)
bitmap_maxno = cma_bitmap_maxno(cma);
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+ atomic_inc(_alloc_counter);
+
for (;;) {
mutex_lock(>lock);
bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
@@ -415,6 +419,8 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned
int align)
start = bitmap_no + mask + 1;
}
+ atomic_dec(_alloc_counter);
+
pr_debug("%s(): returned %p\n", __func__, page);
return page;
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a5bbc38..0622c4c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -66,6 +66,10 @@
#include
#include "internal.h"
+#ifdef CONFIG_CMA
+#include
+#endif
+
/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
static DEFINE_MUTEX(pcp_batch_high_lock);
#define MIN_PERCPU_PAGELIST_FRACTION (8)
@@ -1330,7 +1334,9 @@ static struct page *__rmqueue(struct zone *zone, unsigned
int order,
{
struct page *page = NULL;
- if (IS_ENABLED(CONFIG_CMA) && zone->managed_cma_pages) {
+ if (IS_ENABLED(CONFIG_CMA)
+ && zone->managed_cma_pages
+ && atomic_read(_alloc_counter) == 0) {
if (migratetype == MIGRATE_MOVABLE
&& zone->nr_try_movable <= 0)
page = __rmqueue_cma(zone, order);
--
1.9.1
--
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[PATCH 3/3] CMA: Add cma_alloc_counter to make cma_alloc work better if it meet busy range
In [1], Joonsoo said that cma_alloc_counter is useless because pageblock
is isolated.
But if alloc_contig_range meet a busy range, it will undo_isolate_page_range
before goto try next range. At this time, __rmqueue_cma can begin allocd
CMA memory from the range.
So I add cma_alloc_counter let __rmqueue doesn't call __rmqueue_cma when
cma_alloc works.
[1] https://lkml.org/lkml/2014/10/24/26
Signed-off-by: Hui Zhu zhu...@xiaomi.com
---
include/linux/cma.h | 2 ++
mm/cma.c| 6 ++
mm/page_alloc.c | 8 +++-
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9384ba6..155158f 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -26,6 +26,8 @@ extern int __init cma_declare_contiguous(phys_addr_t base,
extern int cma_init_reserved_mem(phys_addr_t base,
phys_addr_t size, int order_per_bit,
struct cma **res_cma);
+
+extern atomic_t cma_alloc_counter;
extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
extern bool cma_release(struct cma *cma, struct page *pages, int count);
#endif
diff --git a/mm/cma.c b/mm/cma.c
index 6707b5d..b63f6be 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -348,6 +348,8 @@ err:
return ret;
}
+atomic_t cma_alloc_counter = ATOMIC_INIT(0);
+
/**
* cma_alloc() - allocate pages from contiguous area
* @cma: Contiguous memory region for which the allocation is performed.
@@ -378,6 +380,8 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned
int align)
bitmap_maxno = cma_bitmap_maxno(cma);
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+ atomic_inc(cma_alloc_counter);
+
for (;;) {
mutex_lock(cma-lock);
bitmap_no = bitmap_find_next_zero_area_off(cma-bitmap,
@@ -415,6 +419,8 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned
int align)
start = bitmap_no + mask + 1;
}
+ atomic_dec(cma_alloc_counter);
+
pr_debug(%s(): returned %p\n, __func__, page);
return page;
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a5bbc38..0622c4c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -66,6 +66,10 @@
#include asm/div64.h
#include internal.h
+#ifdef CONFIG_CMA
+#include linux/cma.h
+#endif
+
/* prevent 1 _updater_ of zone percpu pageset -high and -batch fields */
static DEFINE_MUTEX(pcp_batch_high_lock);
#define MIN_PERCPU_PAGELIST_FRACTION (8)
@@ -1330,7 +1334,9 @@ static struct page *__rmqueue(struct zone *zone, unsigned
int order,
{
struct page *page = NULL;
- if (IS_ENABLED(CONFIG_CMA) zone-managed_cma_pages) {
+ if (IS_ENABLED(CONFIG_CMA)
+zone-managed_cma_pages
+atomic_read(cma_alloc_counter) == 0) {
if (migratetype == MIGRATE_MOVABLE
zone-nr_try_movable = 0)
page = __rmqueue_cma(zone, order);
--
1.9.1
--
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the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
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