[RFC PATCH 03/19] fs/resctrl: Add new interface max_bandwidth
From: Babu Moger <babu.moger@amd.com>
Date: 2026-01-21 21:13:33
Also in:
kvm, lkml
Subsystem:
documentation, filesystems (vfs and infrastructure), rdt - resource allocation, the rest · Maintainers:
Jonathan Corbet, Alexander Viro, Christian Brauner, Tony Luck, Reinette Chatre, Linus Torvalds
While min_bandwidth is exposed for each resource under /sys/fs/resctrl, the maximum supported bandwidth is not currently shown. Add max_bandwidth to report the maximum bandwidth permitted for a resource. This helps users understand the limits of the associated resource control group. Signed-off-by: Babu Moger <babu.moger@amd.com> --- Documentation/filesystems/resctrl.rst | 6 +++++- fs/resctrl/rdtgroup.c | 17 +++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 45dde8774128..94187dd3c244 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst@@ -224,7 +224,11 @@ Memory bandwidth(MB) subdirectory contains the following files with respect to allocation: "min_bandwidth": - The minimum memory bandwidth percentage which + The minimum memory bandwidth percentage or units which + user can request. + +"max_bandwidth": + The maximum memory bandwidth percentage or units which user can request. "bandwidth_gran":
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index ae6c515f4c19..d2eab9007cc1 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c@@ -1153,6 +1153,16 @@ static int rdt_min_bw_show(struct kernfs_open_file *of, return 0; } +static int rdt_max_bw_show(struct kernfs_open_file *of, + struct seq_file *seq, void *v) +{ + struct resctrl_schema *s = rdt_kn_parent_priv(of->kn); + struct rdt_resource *r = s->res; + + seq_printf(seq, "%u\n", r->membw.max_bw); + return 0; +} + static int rdt_num_rmids_show(struct kernfs_open_file *of, struct seq_file *seq, void *v) {
@@ -1959,6 +1969,13 @@ static struct rftype res_common_files[] = { .seq_show = rdt_min_bw_show, .fflags = RFTYPE_CTRL_INFO | RFTYPE_RES_MB, }, + { + .name = "max_bandwidth", + .mode = 0444, + .kf_ops = &rdtgroup_kf_single_ops, + .seq_show = rdt_max_bw_show, + .fflags = RFTYPE_CTRL_INFO | RFTYPE_RES_MB, + }, { .name = "bandwidth_gran", .mode = 0444,
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2.34.1