From: Babu Moger Date: Thu, 13 Nov 2025 00:57:36 +0000 (-0600) Subject: fs/resctrl: Update bit_usage to reflect io_alloc X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ac7de456a37f9b126eb53b89c2bb27d625dc5fd9;p=thirdparty%2Flinux.git fs/resctrl: Update bit_usage to reflect io_alloc The "shareable_bits" and "bit_usage" resctrl files associated with cache resources give insight into how instances of a cache is used. Update the annotated capacity bitmasks displayed by "bit_usage" to include the cache portions allocated for I/O via the "io_alloc" feature. "shareable_bits" is a global bitmask of shareable cache with I/O and can thus not present the per-domain I/O allocations possible with the "io_alloc" feature. Revise the "shareable_bits" documentation to direct users to "bit_usage" for accurate cache usage information. Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://patch.msgid.link/e02a0d424129fd7f3e45822a559b1c614ae4652a.1762995456.git.babu.moger@amd.com --- diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst index bbc4b6cbb71dc..8c8ce678148a5 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -96,12 +96,19 @@ related to allocation: must be set when writing a mask. "shareable_bits": - Bitmask of shareable resource with other executing - entities (e.g. I/O). User can use this when - setting up exclusive cache partitions. Note that - some platforms support devices that have their - own settings for cache use which can over-ride - these bits. + Bitmask of shareable resource with other executing entities + (e.g. I/O). Applies to all instances of this resource. User + can use this when setting up exclusive cache partitions. + Note that some platforms support devices that have their + own settings for cache use which can over-ride these bits. + + When "io_alloc" is enabled, a portion of each cache instance can + be configured for shared use between hardware and software. + "bit_usage" should be used to see which portions of each cache + instance is configured for hardware use via "io_alloc" feature + because every cache instance can have its "io_alloc" bitmask + configured independently via "io_alloc_cbm". + "bit_usage": Annotated capacity bitmasks showing how all instances of the resource are used. The legend is: @@ -115,16 +122,16 @@ related to allocation: "H": Corresponding region is used by hardware only but available for software use. If a resource - has bits set in "shareable_bits" but not all - of these bits appear in the resource groups' - schematas then the bits appearing in - "shareable_bits" but no resource group will - be marked as "H". + has bits set in "shareable_bits" or "io_alloc_cbm" + but not all of these bits appear in the resource + groups' schemata then the bits appearing in + "shareable_bits" or "io_alloc_cbm" but no + resource group will be marked as "H". "X": Corresponding region is available for sharing and - used by hardware and software. These are the - bits that appear in "shareable_bits" as - well as a resource group's allocation. + used by hardware and software. These are the bits + that appear in "shareable_bits" or "io_alloc_cbm" + as well as a resource group's allocation. "S": Corresponding region is used by software and available for sharing. diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c index 332918fc961a3..b2d178d3556ec 100644 --- a/fs/resctrl/ctrlmondata.c +++ b/fs/resctrl/ctrlmondata.c @@ -750,7 +750,7 @@ out: * resource. Note that if Code Data Prioritization (CDP) is enabled, the number * of available CLOSIDs is reduced by half. */ -static u32 resctrl_io_alloc_closid(struct rdt_resource *r) +u32 resctrl_io_alloc_closid(struct rdt_resource *r) { if (resctrl_arch_get_cdp_enabled(r->rid)) return resctrl_arch_get_num_closid(r) / 2 - 1; diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h index e1eda74881a9a..bff4a54ae3330 100644 --- a/fs/resctrl/internal.h +++ b/fs/resctrl/internal.h @@ -442,6 +442,7 @@ int resctrl_io_alloc_cbm_show(struct kernfs_open_file *of, struct seq_file *seq, void *v); ssize_t resctrl_io_alloc_cbm_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off); +u32 resctrl_io_alloc_closid(struct rdt_resource *r); #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp); diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index 361497489d875..8e39dfda56bc6 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -1062,15 +1062,17 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of, cpus_read_lock(); mutex_lock(&rdtgroup_mutex); - hw_shareable = r->cache.shareable_bits; list_for_each_entry(dom, &r->ctrl_domains, hdr.list) { if (sep) seq_putc(seq, ';'); + hw_shareable = r->cache.shareable_bits; sw_shareable = 0; exclusive = 0; seq_printf(seq, "%d=", dom->hdr.id); for (i = 0; i < closids_supported(); i++) { - if (!closid_allocated(i)) + if (!closid_allocated(i) || + (resctrl_arch_get_io_alloc_enabled(r) && + i == resctrl_io_alloc_closid(r))) continue; ctrl_val = resctrl_arch_get_config(r, dom, i, s->conf_type); @@ -1098,6 +1100,21 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of, break; } } + + /* + * When the "io_alloc" feature is enabled, a portion of the cache + * is configured for shared use between hardware and software. + * Also, when CDP is enabled the CBMs of CDP_CODE and CDP_DATA + * resources are kept in sync. So, the CBMs for "io_alloc" can + * be accessed through either resource. + */ + if (resctrl_arch_get_io_alloc_enabled(r)) { + ctrl_val = resctrl_arch_get_config(r, dom, + resctrl_io_alloc_closid(r), + s->conf_type); + hw_shareable |= ctrl_val; + } + for (i = r->cache.cbm_len - 1; i >= 0; i--) { pseudo_locked = dom->plr ? dom->plr->cbm : 0; hwb = test_bit(i, &hw_shareable);