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From: Tomas Vondra <[email protected]>
To: Christoph Berg <[email protected]>
To: Bertrand Drouvot <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: [email protected]
Subject: Re: pgsql: Introduce pg_shmem_allocations_numa view
Date: Wed, 25 Jun 2025 11:22:41 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

On 6/25/25 11:00, Christoph Berg wrote:
> Re: Bertrand Drouvot
>> +/*
>> + * Work around Linux kernel bug in 32-bit compat mode: do_pages_stat() has
>> + * incorrect pointer arithmetic for more than DO_PAGES_STAT_CHUNK_NR pages.
>> + */
>> +#if SIZEOF_SIZE_T == 4
> 
> I was also missing it in my suggested patch draft, but this should
> probably include #ifdef __linux__.
> 


> 
> Re: Tomas Vondra
>> +#ifdef USE_VALGRIND
>> +
>> +static inline void
>> +pg_numa_touch_mem_if_required(uint64 tmp, char *ptr)
> 
> Stupid question, if this function gets properly inlined, why not
> always use it as there should be no performance difference vs using a
> macro?
> 

TBH I'm not 100% sure it works correctly, I need to check it actually
touches the memory etc. It's possible it was discussed in one of the
earlier NUMA threads, and there are reasons to do a macro.

I also dislike the ifdefs because it adds subtle differences between the
"normal" code and the code tested with valgrind. So just having the
inlined function would be "nicer".

regards

-- 
Tomas Vondra

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