From: "Shawn O. Pearce" <spearce@spearce.org>
To: Junio C Hamano <junkio@cox.net>
Cc: git@vger.kernel.org
Subject: [PATCH 13/17] Ensure core.packedGitWindowSize cannot be less than 2 pages.
Date: Sat, 23 Dec 2006 02:34:38 -0500 [thread overview]
Message-ID: <20061223073438.GN9837@spearce.org> (raw)
In-Reply-To: <53b67707929c7f051f6d384c5d96e653bfa8419c.1166857884.git.spearce@spearce.org>
We cannot allow a window to be smaller than 2 system pages.
This limitation is necessary to support the feature of use_pack()
where we always supply at least 20 bytes after the offset to help
the object header and delta base parsing routines.
If packedGitWindowSize were allowed to be as small as 1 system page
then we would be completely unable to access an object header which
spanned over a page as we would never be able to arrange a mapping
such that the header was contiguous in virtual memory.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
config.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/config.c b/config.c
index a8ea063..edc42f4 100644
--- a/config.c
+++ b/config.c
@@ -302,8 +302,8 @@ int git_default_config(const char *var, const char *value)
int pgsz = getpagesize();
packed_git_window_size = git_config_int(var, value);
packed_git_window_size /= pgsz;
- if (!packed_git_window_size)
- packed_git_window_size = 1;
+ if (packed_git_window_size < 2)
+ packed_git_window_size = 2;
packed_git_window_size *= pgsz;
return 0;
}
--
1.4.4.3.g87d8
next prev parent reply other threads:[~2006-12-23 7:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <53b67707929c7f051f6d384c5d96e653bfa8419c.1166857884.git.spearce@spearce.org>
2006-12-23 7:33 ` [PATCH 1/17] Replace unpack_entry_gently with unpack_entry Shawn O. Pearce
2006-12-23 7:33 ` [PATCH 2/17] Introduce new config option for mmap limit Shawn O. Pearce
2006-12-23 7:33 ` [PATCH 3/17] Refactor packed_git to prepare for sliding mmap windows Shawn O. Pearce
2006-12-23 7:33 ` [PATCH 4/17] Use off_t for index and pack file lengths Shawn O. Pearce
2006-12-23 7:33 ` [PATCH 5/17] Create read_or_die utility routine Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 6/17] Refactor how we open pack files to prepare for multiple windows Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 7/17] Replace use_packed_git with window cursors Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 8/17] Loop over pack_windows when inflating/accessing data Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 9/17] Document why header parsing won't exceed a window Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 10/17] Unmap individual windows rather than entire files Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 11/17] Fully activate the sliding window pack access Shawn O. Pearce
2006-12-23 18:44 ` Linus Torvalds
2006-12-23 19:34 ` Eric Blake
2006-12-24 0:58 ` Johannes Schindelin
2006-12-23 19:45 ` Junio C Hamano
2006-12-23 20:10 ` Linus Torvalds
2006-12-24 1:23 ` Johannes Schindelin
2006-12-24 2:23 ` Shawn Pearce
2006-12-24 2:35 ` Shawn Pearce
2006-12-23 7:34 ` [PATCH 12/17] Load core configuration in git-verify-pack Shawn O. Pearce
2006-12-23 7:34 ` Shawn O. Pearce [this message]
2006-12-23 7:34 ` [PATCH 14/17] Improve error message when packfile mmap fails Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 15/17] Support unmapping windows on 'temporary' packfiles Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 16/17] Create pack_report() as a debugging aid Shawn O. Pearce
2006-12-23 7:34 ` [PATCH 17/17] Test suite for sliding window mmap implementation Shawn O. Pearce
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