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From: Duy Nguyen <pclouds@gmail.com>
To: David Turner <dturner@twopensource.com>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH v5 02/15] read-cache: allow to keep mmap'd memory after reading
Date: Wed, 20 Apr 2016 16:26:34 +0700	[thread overview]
Message-ID: <CACsJy8D229ARqEjH29Gqd=u8KijGA_Fzk0cbUNRXB9GA0ittMg@mail.gmail.com> (raw)
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

  parent reply	other threads:[~2016-04-20  9:27 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-19 23:27 [PATCH v5 00/15] index-helper/watchman David Turner
2016-04-19 23:27 ` [PATCH v5 01/15] read-cache.c: fix constness of verify_hdr() David Turner
2016-04-19 23:27 ` [PATCH v5 02/15] read-cache: allow to keep mmap'd memory after reading David Turner
2016-04-20  9:01   ` Johannes Schindelin
2016-04-20 19:41     ` David Turner
2016-04-20  9:26   ` Duy Nguyen [this message]
2016-04-20 19:43     ` David Turner
2016-04-19 23:27 ` [PATCH v5 03/15] index-helper: new daemon for caching index and related stuff David Turner
2016-04-20 12:17   ` Johannes Schindelin
2016-04-20 12:31     ` Duy Nguyen
2016-04-20 19:38     ` David Turner
2016-04-19 23:27 ` [PATCH v5 04/15] index-helper: add --strict David Turner
2016-04-19 23:27 ` [PATCH v5 05/15] daemonize(): set a flag before exiting the main process David Turner
2016-04-19 23:28 ` [PATCH v5 06/15] index-helper: add --detach David Turner
2016-04-19 23:50   ` Duy Nguyen
2016-04-20  1:04     ` David Turner
2016-04-20  9:33       ` Duy Nguyen
2016-04-25 20:53     ` David Turner
2016-04-19 23:28 ` [PATCH v5 07/15] read-cache: add watchman 'WAMA' extension David Turner
2016-04-19 23:28 ` [PATCH v5 08/15] Add watchman support to reduce index refresh cost David Turner
2016-04-19 23:28 ` [PATCH v5 09/15] index-helper: use watchman to avoid refreshing index with lstat() David Turner
2016-04-20  0:15   ` Duy Nguyen
2016-04-20  1:01     ` David Turner
2016-04-20  9:36       ` Duy Nguyen
2016-04-19 23:28 ` [PATCH v5 10/15] update-index: enable/disable watchman support David Turner
2016-04-19 23:45   ` Duy Nguyen
2016-04-20 19:50     ` David Turner
2016-04-19 23:28 ` [PATCH v5 11/15] unpack-trees: preserve index extensions David Turner
2016-04-19 23:28 ` [PATCH v5 12/15] index-helper: kill mode David Turner
2016-04-19 23:28 ` [PATCH v5 13/15] index-helper: don't run if already running David Turner
2016-04-19 23:28 ` [PATCH v5 14/15] index-helper: autorun mode David Turner
2016-04-19 23:28 ` [PATCH v5 15/15] index-helper: optionally automatically run David Turner
2016-04-20  9:59   ` [PATCH 16/15] Add tracing to measure where most of the time is spent Nguyễn Thái Ngọc Duy
2016-04-20 12:28     ` Johannes Schindelin
2016-04-20 12:36       ` Duy Nguyen

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