I do like that the article touches exactly this, and even though I'm a stranger to the entire concept, it makes sense:
>Hardly anyone hitchhikes any more, which is a shame because it encourages the habit of generosity from drivers, and it nurtures the grace of gratitude and patience of being kinded from hikers
What if your young 'uns just do not... participate?
I am in a position where I am doing TL-level decisions, and try quite hard to demo, discuss, share the details and rationale. I write design proposals, documentation, do demo sessions, etc
But the information is just not flowing, and I notice how little the juniors participate in anything. And I don't exactly know what to put my finger on. It's probably some soft-skill I'm lacking, and that I do not know how to improve
But a part of me still feels that that perhaps the young 'uns are just... too fresh. Or that the approach is just too optimistic
Yes, all allocators (except perhaps OpenBSDs from what I see in this thread) do this. It is also why `calloc` exists - because zero-initializing every single allocation is really, really expensive.
>I'd never heard of the Robson bounds but they seem quite crucial to know about
I'd argue it's not really important in modern systems due to the use of virtual memory. With virtual memory, you can massive reduce fragmentation since you are no longer managing a single continuous region of memory.
Fragmentation still exists, but it only applies to "small" allocations (think smaller than a page) and in most scenarios it is a result of modern memory allocators preferring performance over reduced memory usage. Memory is cheap nowadays, and performance is king.
>Does anyone have some kind of list of the most important results in the area of memory management?
There is a survey [1] on the subject of memory allocation that mentions Robson's bounds and other results
>It's applicable to C because most realistic implementations of malloc(3) store the size of the malloc'd area to the nearest word[2]
This is not so true anymore, and I'd be very careful with that sort of tricks. While the default memory allocator on most distributions (ptmalloc2) still probably works like that, there are other memory allocators in use like jemalloc/tcmalloc, which store metadata for a group of blocks (e.g all equal-sized blocks in a page) rather than for every single block.
Like Asooka wrote, you can malloc_usable_size(), if available. But have in mind that malloc_usable_size() returns the size of the block that malloc has given you, which can be _larger_ than the size you requested, as many memory allocators round block sizes up.
There's malloc_usable_size[1], assuming you mean asking the memory allocator what the array size is. But chances are that wouldn't work correctly, because what the amount of memory a malloc calls gives you and the amount you requested are often not the same. Modern memory allocators round up the request size to the nearest "size class".
>Hardly anyone hitchhikes any more, which is a shame because it encourages the habit of generosity from drivers, and it nurtures the grace of gratitude and patience of being kinded from hikers
I can see how it becomes a healthy feedback loop