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    Subject[tip:x86/cache] x86/intel_rdt: Enable entering of pseudo-locksetup mode
    Commit-ID:  139a67166b274176ee804260cb2c4c6de5689535
    Gitweb: https://git.kernel.org/tip/139a67166b274176ee804260cb2c4c6de5689535
    Author: Reinette Chatre <reinette.chatre@intel.com>
    AuthorDate: Thu, 7 Jun 2018 14:26:44 -0700
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Wed, 20 Jun 2018 00:56:36 +0200

    x86/intel_rdt: Enable entering of pseudo-locksetup mode

    The user can request entering pseudo-locksetup mode by writing
    "pseudo-locksetup" to the mode file. Act on this request as well as
    support switching from a pseudo-locksetup mode (before pseudo-locked
    mode was entered). It is not supported to modify the mode once
    pseudo-locked mode has been entered.

    The schemata reflects the new mode by adding "uninitialized" to all
    resources. The size resctrl file reports zero for all cache domains in
    support of the uninitialized nature. Since there are no users of this
    class of service its allocations can be ignored when searching for
    appropriate default allocations for new resource groups. For the same
    reason resource groups in pseudo-locksetup mode are not considered when
    testing if new resource groups may overlap.

    Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: fenghua.yu@intel.com
    Cc: tony.luck@intel.com
    Cc: vikas.shivappa@linux.intel.com
    Cc: gavin.hindman@intel.com
    Cc: jithu.joseph@intel.com
    Cc: dave.hansen@intel.com
    Cc: hpa@zytor.com
    Link: https://lkml.kernel.org/r/bbf8b7d6985e7a4df508cdc141e01b2d5c92372b.1528405411.git.reinette.chatre@intel.com

    ---
    arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 16 +++++++----
    arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 41 +++++++++++++++++++++++++----
    2 files changed, 47 insertions(+), 10 deletions(-)

    diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
    index bc79396c5dad..1ed273220ffa 100644
    --- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
    +++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
    @@ -156,7 +156,8 @@ int parse_cbm(void *_data, struct rdt_resource *r, struct rdt_domain *d)
    }

    if (rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, false)) {
    - if (rdtgrp->mode == RDT_MODE_EXCLUSIVE) {
    + if (rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
    + rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
    rdt_last_cmd_printf("overlaps with other group\n");
    return -EINVAL;
    }
    @@ -356,10 +357,15 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of,

    rdtgrp = rdtgroup_kn_lock_live(of->kn);
    if (rdtgrp) {
    - closid = rdtgrp->closid;
    - for_each_alloc_enabled_rdt_resource(r) {
    - if (closid < r->num_closid)
    - show_doms(s, r, closid);
    + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
    + for_each_alloc_enabled_rdt_resource(r)
    + seq_printf(s, "%s:uninitialized\n", r->name);
    + } else {
    + closid = rdtgrp->closid;
    + for_each_alloc_enabled_rdt_resource(r) {
    + if (closid < r->num_closid)
    + show_doms(s, r, closid);
    + }
    }
    } else {
    ret = -ENOENT;
    diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
    index e27583f3823e..8f50914dc45e 100644
    --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
    +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
    @@ -974,9 +974,10 @@ bool rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
    ctrl = d->ctrl_val;
    for (i = 0; i < r->num_closid; i++, ctrl++) {
    ctrl_b = (unsigned long *)ctrl;
    - if (closid_allocated(i) && i != closid) {
    + mode = rdtgroup_mode_by_closid(i);
    + if (closid_allocated(i) && i != closid &&
    + mode != RDT_MODE_PSEUDO_LOCKSETUP) {
    if (bitmap_intersects(cbm, ctrl_b, r->cache.cbm_len)) {
    - mode = rdtgroup_mode_by_closid(i);
    if (exclusive) {
    if (mode == RDT_MODE_EXCLUSIVE)
    return true;
    @@ -1046,10 +1047,24 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
    mode = rdtgrp->mode;

    if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE) ||
    - (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE))
    + (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE) ||
    + (!strcmp(buf, "pseudo-locksetup") &&
    + mode == RDT_MODE_PSEUDO_LOCKSETUP) ||
    + (!strcmp(buf, "pseudo-locked") && mode == RDT_MODE_PSEUDO_LOCKED))
    goto out;

    + if (mode == RDT_MODE_PSEUDO_LOCKED) {
    + rdt_last_cmd_printf("cannot change pseudo-locked group\n");
    + ret = -EINVAL;
    + goto out;
    + }
    +
    if (!strcmp(buf, "shareable")) {
    + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
    + ret = rdtgroup_locksetup_exit(rdtgrp);
    + if (ret)
    + goto out;
    + }
    rdtgrp->mode = RDT_MODE_SHAREABLE;
    } else if (!strcmp(buf, "exclusive")) {
    if (!rdtgroup_mode_test_exclusive(rdtgrp)) {
    @@ -1057,7 +1072,17 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
    ret = -EINVAL;
    goto out;
    }
    + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
    + ret = rdtgroup_locksetup_exit(rdtgrp);
    + if (ret)
    + goto out;
    + }
    rdtgrp->mode = RDT_MODE_EXCLUSIVE;
    + } else if (!strcmp(buf, "pseudo-locksetup")) {
    + ret = rdtgroup_locksetup_enter(rdtgrp);
    + if (ret)
    + goto out;
    + rdtgrp->mode = RDT_MODE_PSEUDO_LOCKSETUP;
    } else {
    rdt_last_cmd_printf("unknown/unsupported mode\n");
    ret = -EINVAL;
    @@ -1127,8 +1152,12 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
    list_for_each_entry(d, &r->domains, list) {
    if (sep)
    seq_putc(s, ';');
    - cbm = d->ctrl_val[rdtgrp->closid];
    - size = rdtgroup_cbm_to_size(r, d, cbm);
    + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
    + size = 0;
    + } else {
    + cbm = d->ctrl_val[rdtgrp->closid];
    + size = rdtgroup_cbm_to_size(r, d, cbm);
    + }
    seq_printf(s, "%d=%u", d->id, size);
    sep = true;
    }
    @@ -2269,6 +2298,8 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
    for (i = 0; i < r->num_closid; i++, ctrl++) {
    if (closid_allocated(i) && i != closid) {
    mode = rdtgroup_mode_by_closid(i);
    + if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
    + break;
    used_b |= *ctrl;
    if (mode == RDT_MODE_SHAREABLE)
    d->new_ctrl |= *ctrl;
    \
     
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