From 5a88a6e92bbf5963fadeb0e8f8c747c2fb425ba8 Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Mon, 17 Nov 2025 16:42:45 -0800 Subject: [PATCH] fs/resctrl: Consider sparse masks when initializing new group's allocation A new resource group is intended to be created with sane defaults. For a cache resource this means all cache portions the new group could possibly allocate into. This includes unused cache portions and shareable cache portions used by other groups and hardware. New resource group creation does not take sparse masks into account. After determining the bitmask reflecting the new group's possible allocations the bitmask is forced to be contiguous even if the system supports sparse masks. For example, a new group could by default allocate into a large portion of cache represented by 0xff0f, but it is instead created with a mask of 0xf. Do not force a contiguous allocation range if the system supports sparse masks. Signed-off-by: Reinette Chatre Signed-off-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/abbbb008bc09d982d715e79d3b885c10f92c64e0.1763426240.git.reinette.chatre@intel.com --- fs/resctrl/rdtgroup.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index 0320360cd7a6e..41ce4b377af42 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -3383,11 +3383,12 @@ static u32 cbm_ensure_valid(u32 _val, struct rdt_resource *r) { unsigned int cbm_len = r->cache.cbm_len; unsigned long first_bit, zero_bit; - unsigned long val = _val; + unsigned long val; - if (!val) - return 0; + if (!_val || r->cache.arch_has_sparse_bitmasks) + return _val; + val = _val; first_bit = find_first_bit(&val, cbm_len); zero_bit = find_next_zero_bit(&val, cbm_len, first_bit); -- 2.47.3