From: Duy Nguyen <pclouds@gmail.com>
Date: Wed, 20 Apr 2016 09:26:34 GMT
Subject: Re: [PATCH v5 02/15] read-cache: allow to keep mmap'd memory after reading
Message-ID: <CACsJy8D229ARqEjH29Gqd=u8KijGA_Fzk0cbUNRXB9GA0ittMg@mail.gmail.com>
In-Reply-To: <1461108489-29376-3-git-send-email-dturner@twopensource.com>

On Wed, Apr 20, 2016 at 6:27 AM, David Turner <dturner@twopensource.com> wrote:
> From: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>
> Later, we will introduce git index-helper to share this memory with
> other git processes.
>
> Since the memory will be shared, it will never be unmapped (although
> the kernel may of course choose to page it out).

This is not entirely true. We do need to keep the mmap'd memory for
longer, even after read_index_from() finishes. But we do not share the
exact same address space to other processes (memcpy is used in
index-helper.c:share_index()). We could even discard_index() at the
end of share_index(), but I think we keep it anyway just in case
another process asks, or when index is not updated.
-- 
Duy