The idea behind the sliding mmap window pack reader implementation
is to have multiple mmap regions active against the same pack file,
thereby allowing the process to mmap in only the active/hot sections
of the pack and reduce overall virtual address space usage.
To implement this we need to refactor the mmap related data
(pack_base, pack_use_cnt) out of struct packed_git and move them
into a new struct pack_window.
We are refactoring the code to support a single struct pack_window
per packfile, thereby emulating the prior behavior of mmap'ing the
entire pack file.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The unpack_entry_gently function currently has only two callers:
the delta base resolution in sha1_file.c and the main loop of
pack-check.c. Both of these must change to using unpack_entry
directly when we implement sliding window mmap logic, so I'm doing
it earlier to help break down the change set.
This may cause a slight performance decrease for delta base
resolution as well as for pack-check.c's verify_packfile(), as
the pack use counter will be incremented and decremented for every
object that is unpacked.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Those cleanups are mainly to set the table for the support of deltas
with base objects referenced by offsets instead of sha1. This means
that many pack lookup functions are converted to take a pack/offset
tuple instead of a sha1.
This eliminates many struct pack_entry usages since this structure
carried redundent information in many cases, and it increased stack
footprint needlessly for a couple recursively called functions that used
to declare a local copy of it for every recursion loop.
In the process, packed_object_info_detail() has been reorganized as well
so to look much saner and more amenable to deltas with offset support.
Finally the appropriate adjustments have been made to functions that
depend on the above changes. But there is no functionality changes yet
simply some code refactoring at this point.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Introduces global inline:
hashcmp(const unsigned char *sha1, const unsigned char *sha2)
Uses memcmp for comparison and returns the result based on the length of
the hash name (a future runtime decision).
Acked-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
ANSI C99 doesn't allow void-pointer arithmetic. This patch fixes this in
various ways. Usually the strategy that required the least changes was used.
Signed-off-by: Florian Forster <octo@verplant.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Check internal integrity to report corrupt pack or idx, and
then check cross-integrity between idx and pack.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
After experimenting with code to add the ability to encode a delta
against part of the deltified file, it turns out that resulting packs
are _bigger_ than when this ability is not used. The raw delta output
might be smaller, but it doesn't compress as well using gzip with a
negative net saving on average.
Said bit would in fact be more useful to allow for encoding the copying
of chunks larger than 64KB providing more savings with large files.
This will correspond to packs version 3.
While the current code still produces packs version 2, it is made future
proof so pack versions 2 and 3 are accepted. Any pack version 2 are
compatible with version 3 since the redefined bit was never used before.
When enough time has passed, code to use that bit to produce version 3
packs could be added.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
GCC's format __attribute__ is good for checking errors, especially
with -Wformat=2 parameter. This fixes most of the reported problems
against 2005-08-09 snapshot.
This implements show_pack_info() function used in verify-pack
command when -v flag is used to obtain something like
unpack-objects used to give when it was first written.
It shows the following for each non-deltified object found in
the pack:
SHA1 type size offset
For deltified objects, it shows this instead:
SHA1 type size offset depth base_sha1
In order to get the output in the order that appear in the pack
file for debugging purposes, you can do this:
$ git-verify-pack -v packfile | sort -n -k 4,4
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Nico pointed out that having verify_pack.c and verify-pack.c was
confusing. Rename verify_pack.c to pack-check.c as suggested,
and enhances the verification done quite a bit.
- Built-in sha1_file unpacking knows that a base object of a
deltified object _must_ be in the same pack, and takes
advantage of that fact.
- Earlier verify-pack command only checked the SHA1 sum for the
entire pack file and did not look into its contents. It now
checks everything idx file claims to have unpacks correctly.
- It now has a hook to give more detailed information for
objects contained in the pack under -v flag.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
