Messages in this thread | | | Date | Fri, 28 Jul 2023 17:34:29 +0100 | Subject | Re: [PATCH v4 15/24] x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() | From | James Morse <> |
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Hi Shaopeng TAN,
On 12/06/2023 06:39, Shaopeng Tan (Fujitsu) wrote: >> Depending on the number of monitors available, Arm's MPAM may need to >> allocate a monitor prior to reading the counter value. Allocating a contended >> resource may involve sleeping. >> >> add_rmid_to_limbo() calls resctrl_arch_rmid_read() for multiple domains, the >> allocation should be valid for all domains. >> >> __check_limbo() and mon_event_count() each make multiple calls to >> resctrl_arch_rmid_read(), to avoid extra work on contended systems, the >> allocation should be valid for multiple invocations of resctrl_arch_rmid_read(). >> >> Add arch hooks for this allocation, which need calling before >> resctrl_arch_rmid_read(). The allocated monitor is passed to >> resctrl_arch_rmid_read(), then freed again afterwards. The helper can be >> called on any CPU, and can sleep.
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c >> b/arch/x86/kernel/cpu/resctrl/monitor.c >> index fb33100e172b..6d140018358a 100644 >> --- a/arch/x86/kernel/cpu/resctrl/monitor.c >> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -331,9 +331,14 @@ void __check_limbo(struct rdt_domain *d, bool force_free) >> u32 idx_limit = resctrl_arch_system_num_rmid_idx(); >> struct rmid_entry *entry; >> u32 idx, cur_idx = 1; >> + void *arch_mon_ctx; >> bool rmid_dirty; >> u64 val = 0; >> >> + arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, >> QOS_L3_OCCUP_EVENT_ID); >> + if (arch_mon_ctx < 0) >> + return; >> + > > Would it be better to use IS_ERR() macro?
Yup, much more readable!
Thanks,
James
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