Messages in this thread | | | Date | Thu, 14 Dec 2023 11:38:02 +0000 | Subject | Re: [PATCH v7 15/24] x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() | From | James Morse <> |
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Hi Babu,
On 09/11/2023 20:47, Moger, Babu wrote: > On 10/25/23 13:03, James Morse 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. > > This above sentence does not look correct after your previous patch [patch > 14]. You removed resctrl_arch_rmid_read() from add_rmid_to_limbo().
Ah, this was the justification for making the allocated resource global, when the patches were in a different order. It's also simpler to make them global. I've removed this paragraph, and replaced it with: | The memory or hardware allocated is not specific to a domain.
(its fairly obvious from the interface, but I felt it needed calling out in the commit message)
> Otherwise looks good. > >> >> __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.
> Reviewed-by: Babu Moger <babu.moger@amd.com>
Thanks!
James
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