From: Stefan Roesch shr@devkernel.io
mainline inclusion from mainline-v6.2-rc1 commit 1bf27e98d26d1e62166a456ef17460be085cbe0b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAN96I
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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 Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- include/linux/backing-dev.h | 1 + mm/page-writeback.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+)
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 91bc6e9adb14..62e15821ff1c 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -110,6 +110,7 @@ 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 e0de996c1c55..b13965fff44c 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> @@ -683,6 +684,28 @@ 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; @@ -755,6 +778,20 @@ 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)