From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 10 Jun 2026 14:51:19 GMT
Subject: Re: [PATCH v3] index-pack: retain child bases in delta cache
Message-ID: <xmqqldcmxxco.fsf@gitster.g>
In-Reply-To: <08B48BBE-4084-4619-94B0-503158B93BEF@gmail.com>

Arijit Banerjee <arijit91@gmail.com> writes:

> Apologies, my earlier replies were sent through GitHub's notification
> emails and appeared only as PR comments, so they did not reach the mailing
> list.
>
> On Thu, Jun 4, 2026, Jeff King wrote:
>> So I am happy with either v2 or v3.
>
> I also did not see a meaningful performance difference between v2 and v3.
> I am happy with either direction and defer to the maintainers on whether
> v3's more precise release is worth the added complexity.

I have no strong preference either way.

> On Wed, Jun 3, 2026, Derrick Stolee wrote:
>> Did you see any evidence that this change has the intended effect of
>> reducing process memory proactively instead of relying on cache evictions?
>
> I do not have strong RSS evidence. The spot checks showed no meaningful RSS
> change, and max RSS is not a good signal here because free_base_data()
> lowers Git's internal base_cache_used accounting but may not return pages
> to the OS or reduce the recorded peak.
>
> The evidence for v3 is therefore structural: it releases the cached data
> once all direct children have been dispatched and retain_data reaches zero,
> rather than waiting for cache-pressure eviction.