summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorStefan Roesch <shr@devkernel.io>2022-11-19 03:52:02 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-12-01 02:59:04 +0300
commit1bf27e98d26d1e62166a456ef17460be085cbe0b (patch)
tree3234f844db72d37499676681018b3ee62430b91a
parentefc3e6ad53ea14225b434fddca261c9a1c56c707 (diff)
downloadlinux-1bf27e98d26d1e62166a456ef17460be085cbe0b.tar.xz
mm: add bdi_set_max_bytes() function
This introduces the bdi_set_max_bytes() function. The max_bytes function does not store the max_bytes value. Instead it converts the max_bytes value into the corresponding ratio value. Link: https://lkml.kernel.org/r/20221119005215.3052436-8-shr@devkernel.io Signed-off-by: Stefan Roesch <shr@devkernel.io> Cc: Chris Mason <clm@meta.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--include/linux/backing-dev.h1
-rw-r--r--mm/page-writeback.c37
2 files changed, 38 insertions, 0 deletions
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 473686c32775..ea6c993433d5 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -108,6 +108,7 @@ static inline unsigned long wb_stat_error(void)
u64 bdi_get_max_bytes(struct backing_dev_info *bdi);
int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
+int bdi_set_max_bytes(struct backing_dev_info *bdi, u64 max_bytes);
int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit);
/*
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e74ef596dc27..20ae9adeb22f 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -13,6 +13,7 @@
*/
#include <linux/kernel.h>
+#include <linux/math64.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
@@ -650,6 +651,28 @@ void wb_domain_exit(struct wb_domain *dom)
*/
static unsigned int bdi_min_ratio;
+static int bdi_check_pages_limit(unsigned long pages)
+{
+ unsigned long max_dirty_pages = global_dirtyable_memory();
+
+ if (pages > max_dirty_pages)
+ return -EINVAL;
+
+ return 0;
+}
+
+static unsigned long bdi_ratio_from_pages(unsigned long pages)
+{
+ unsigned long background_thresh;
+ unsigned long dirty_thresh;
+ unsigned long ratio;
+
+ global_dirty_limits(&background_thresh, &dirty_thresh);
+ ratio = div64_u64(pages * 100ULL * BDI_RATIO_SCALE, dirty_thresh);
+
+ return ratio;
+}
+
static u64 bdi_get_bytes(unsigned int ratio)
{
unsigned long background_thresh;
@@ -722,6 +745,20 @@ u64 bdi_get_max_bytes(struct backing_dev_info *bdi)
return bdi_get_bytes(bdi->max_ratio);
}
+int bdi_set_max_bytes(struct backing_dev_info *bdi, u64 max_bytes)
+{
+ int ret;
+ unsigned long pages = max_bytes >> PAGE_SHIFT;
+ unsigned long max_ratio;
+
+ ret = bdi_check_pages_limit(pages);
+ if (ret)
+ return ret;
+
+ max_ratio = bdi_ratio_from_pages(pages);
+ return __bdi_set_max_ratio(bdi, max_ratio);
+}
+
int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit)
{
if (strict_limit > 1)