This patch introduces a new "guarantee" property for shared-dma-pool.
With this property, admin can create specific memory pool as
GCMA-based CMA if they care about allocation success rate and latency.
The downside of GCMA is that it can host only clean file-backed pages
since it's using cleancache as its secondary user.
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
arch/powerpc/kernel/fadump.c | 2 +-
include/linux/cma.h | 2 +-
kernel/dma/contiguous.c | 11 ++++++++++-
mm/cma.c | 33 ++++++++++++++++++++++++++-------
mm/cma.h | 1 +
mm/cma_sysfs.c | 10 ++++++++++
6 files changed, 49 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 4b371c738213..4eb7be0cdcdb 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -111,7 +111,7 @@ void __init fadump_cma_init(void)
return;
}
- rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma);
+ rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma, false);
if (rc) {
pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc);
/*
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 62d9c1cf6326..3207db979e94 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -46,7 +46,7 @@ extern int __init cma_declare_contiguous_multi(phys_addr_t size,
extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
unsigned int order_per_bit,
const char *name,
- struct cma **res_cma);
+ struct cma **res_cma, bool gcma);
extern struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align,
bool no_warn);
extern bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned long count);
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 055da410ac71..a68b3123438c 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -459,6 +459,7 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
unsigned long node = rmem->fdt_node;
bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
struct cma *cma;
+ bool gcma;
int err;
if (size_cmdline != -1 && default_cma) {
@@ -476,7 +477,15 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
return -EINVAL;
}
- err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
+ gcma = !!of_get_flat_dt_prop(node, "guarantee", NULL);
+#ifndef CONFIG_GCMA
+ if (gcma) {
+ pr_err("Reserved memory: unable to setup GCMA region, GCMA is not enabled\n");
+ return -EINVAL;
+ }
+#endif
+ err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name,
+ &cma, gcma);
if (err) {
pr_err("Reserved memory: unable to setup CMA region\n");
return err;
diff --git a/mm/cma.c b/mm/cma.c
index b06d5fe73399..f12cef849e58 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -26,6 +26,7 @@
#include <linux/cma.h>
#include <linux/highmem.h>
#include <linux/io.h>
+#include <linux/gcma.h>
#include <linux/kmemleak.h>
#include <trace/events/cma.h>
@@ -165,11 +166,18 @@ static void __init cma_activate_area(struct cma *cma)
count = cmr->early_pfn - cmr->base_pfn;
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
bitmap_set(cmr->bitmap, 0, bitmap_count);
+ } else {
+ count = 0;
}
- for (pfn = cmr->early_pfn; pfn < cmr->base_pfn + cmr->count;
- pfn += pageblock_nr_pages)
- init_cma_reserved_pageblock(pfn_to_page(pfn));
+ if (cma->gcma) {
+ gcma_register_area(cma->name, cmr->early_pfn,
+ cma->count - count);
+ } else {
+ for (pfn = cmr->early_pfn; pfn < cmr->base_pfn + cmr->count;
+ pfn += pageblock_nr_pages)
+ init_cma_reserved_pageblock(pfn_to_page(pfn));
+ }
}
spin_lock_init(&cma->lock);
@@ -270,7 +278,7 @@ static void __init cma_drop_area(struct cma *cma)
int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
unsigned int order_per_bit,
const char *name,
- struct cma **res_cma)
+ struct cma **res_cma, bool gcma)
{
struct cma *cma;
int ret;
@@ -301,6 +309,7 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
cma->ranges[0].count = cma->count;
cma->nranges = 1;
cma->nid = NUMA_NO_NODE;
+ cma->gcma = gcma;
*res_cma = cma;
@@ -721,7 +730,8 @@ static int __init __cma_declare_contiguous_nid(phys_addr_t base,
base = addr;
}
- ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
+ ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma,
+ false);
if (ret)
memblock_phys_free(base, size);
@@ -815,7 +825,13 @@ static int cma_range_alloc(struct cma *cma, struct cma_memrange *cmr,
pfn = cmr->base_pfn + (bitmap_no << cma->order_per_bit);
mutex_lock(&cma->alloc_mutex);
- ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, gfp);
+ if (cma->gcma) {
+ gcma_alloc_range(pfn, count);
+ ret = 0;
+ } else {
+ ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
+ gfp);
+ }
mutex_unlock(&cma->alloc_mutex);
if (ret == 0) {
page = pfn_to_page(pfn);
@@ -992,7 +1008,10 @@ bool cma_release(struct cma *cma, const struct page *pages,
if (r == cma->nranges)
return false;
- free_contig_range(pfn, count);
+ if (cma->gcma)
+ gcma_free_range(pfn, count);
+ else
+ free_contig_range(pfn, count);
cma_clear_bitmap(cma, cmr, pfn, count);
cma_sysfs_account_release_pages(cma, count);
trace_cma_release(cma->name, pfn, pages, count);
diff --git a/mm/cma.h b/mm/cma.h
index 41a3ab0ec3de..c2a5576d7987 100644
--- a/mm/cma.h
+++ b/mm/cma.h
@@ -47,6 +47,7 @@ struct cma {
char name[CMA_MAX_NAME];
int nranges;
struct cma_memrange ranges[CMA_MAX_RANGES];
+ bool gcma;
#ifdef CONFIG_CMA_SYSFS
/* the number of CMA page successful allocations */
atomic64_t nr_pages_succeeded;
diff --git a/mm/cma_sysfs.c b/mm/cma_sysfs.c
index 97acd3e5a6a5..4ecc36270a4d 100644
--- a/mm/cma_sysfs.c
+++ b/mm/cma_sysfs.c
@@ -80,6 +80,15 @@ static ssize_t available_pages_show(struct kobject *kobj,
}
CMA_ATTR_RO(available_pages);
+static ssize_t gcma_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct cma *cma = cma_from_kobj(kobj);
+
+ return sysfs_emit(buf, "%d\n", cma->gcma);
+}
+CMA_ATTR_RO(gcma);
+
static void cma_kobj_release(struct kobject *kobj)
{
struct cma *cma = cma_from_kobj(kobj);
@@ -95,6 +104,7 @@ static struct attribute *cma_attrs[] = {
&release_pages_success_attr.attr,
&total_pages_attr.attr,
&available_pages_attr.attr,
+ &gcma_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(cma);
--
2.49.0.rc1.451.g8f38331e32-goog
