Re: madvise(MADV_FREE) doesn't work in some cases?

From: Vitaliy Gusev <gusev.vitaliy_at_gmail.com>
Date: Tue, 13 Jul 2021 01:51:00 +0300
> On 12 Jul 2021, at 22:52, Konstantin Belousov <kostikbel_at_gmail.com> wrote:
> 
> On Mon, Jul 12, 2021 at 02:55:37PM +0300, Vitaliy Gusev wrote:
>> I guess madvise() should work well even with PAGE_SIZE granularity. Usually a caller doesn’t need to free the whole region. As I reported earlier madvise(PAGE_SIZE) works well in Linux and illumos. 
>> 
>> Current behaviour in FreeBSD can confuse programmers and brings impossibility to effectively give back unused memory. Also I have another case with madvise() but with shared memory that also doesn’t work (but works in Linux and illumos), will report it in new thread.
>> 
> 
> I want the confirmation or report that it still did not worked, for the
> case when my latest patch was applied and the test program switched to
> the single call to madvise(2) for the whole region.
> 

Understood,  checked.

Patched kernel with single call of madvise(len, MADV_FREE) from userspace still doesn’t work. The same condition if (obj->backing_object != NULL) is met, but once.

——
Vitaliy Gusev


> After that, I can claim that the problem is understood and might consider
> some solutions.
Received on Mon Jul 12 2021 - 22:51:00 UTC

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