RFR: 8318817: Could not reserve enough space in CodeHeap 'profiled nmethods' (0K) [v4]

[Thomas Stuefe]

On Wed, 1 Nov 2023 07:12:43 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

>> src/hotspot/share/code/codeCache.cpp line 204:
>> 
>>> 202:   bool non_profiled_set     = FLAG_IS_CMDLINE(NonProfiledCodeHeapSize);
>>> 203:   const size_t ps           = page_size(false, 8);
>>> 204:   const size_t min_size     = MAX2(os::vm_allocation_granularity(), ps);
>> 
>> There is no need for this, nor for the assert below. We know what these sizes are, and their relationship to each other. 
>> 
>> AIX: ps <= os::vm_page_size == alloc granularity
>> Windows: ps == os::vm_page_size < alloc granularity
>> Everyone else: ps == os::vm_page_size == alloc granularity
>> 
>> If it weren't so, a lot of things would break. Just use alloc granularity.
>
>> Windows: ps == os::vm_page_size < alloc granularity
>> Everyone else: ps == os::vm_page_size == alloc granularity
> 
> For Linux using `-XX:+UseTransparentHugePages` and Windows using `-XX:+UseLargePages`, I see `ps > os::vm_page_size()` and `ps > os::vm_allocation_granularity()`.

Oh right, my bad. I thought it calls the system pagesize function. Okay, then the max2 makes sense. I'd still remove the assert though.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16373#discussion_r1378481162