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6ee68611
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2012-09-10T21:29:07
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cache: fix race condition
Example: a cached node is owned only by the cache (refcount == 1).
Thread A holds the lock and determines that the entry which should get
cached equals the node (git_oid_cmp(&node->oid, &entry->oid) == 0).
It frees the given entry to instead return the cached node to the user
(entry = node). Now, before Thread A happens to increment the refcount
of the node *outside* the cache lock, Thread B tries to store another
entry and hits the slot of the node before, decrements its refcount and
frees it *before* Thread A gets a chance to increment for the user.
git_cached_obj_incref(entry);
git_mutex_lock(&cache->lock);
{
git_cached_obj *node = cache->nodes[hash & cache->size_mask];
if (node == NULL) {
cache->nodes[hash & cache->size_mask] = entry;
} else if (git_oid_cmp(&node->oid, &entry->oid) == 0) {
git_cached_obj_decref(entry, cache->free_obj);
entry = node;
} else {
git_cached_obj_decref(node, cache->free_obj);
// Thread B is here
cache->nodes[hash & cache->size_mask] = entry;
}
}
git_mutex_unlock(&cache->lock);
// Thread A is here
/* increase the refcount again, because we are
* returning it to the user */
git_cached_obj_incref(entry);
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c07d9c95
|
2012-08-09T15:33:04
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oid: Explicitly include `oid.h` for the inlined CMP
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3f035860
|
2012-06-07T22:43:03
|
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misc: Fix warnings from PVS Studio trial
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|
25f258e7
|
2012-04-23T09:21:15
|
|
Moving power-of-two bit utilities into util.h
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0d0fa7c3
|
2012-03-16T15:56:01
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|
Convert attr, ignore, mwindow, status to new errors
Also cleaned up some previously converted code that still had
little things to polish.
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5e0de328
|
2012-02-13T17:10:24
|
|
Update Copyright header
Signed-off-by: schu <schu-github@schulog.org>
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e4b4da14
|
2012-01-27T18:28:02
|
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cache: Simplify locking mechanics
The object cache is mostly IO-bound, so it makes no sense to have a lock
per node.
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3286c408
|
2011-10-28T14:51:13
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global: Properly use `git__` memory wrappers
Ensure that all memory related functions (malloc, calloc, strdup, free,
etc) are using their respective `git__` wrappers.
|
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71a4c1f1
|
2011-09-18T20:07:59
|
|
Merge pull request #384 from kiryl/warnings
Add more -W flags to CFLAGS
|
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bb742ede
|
2011-09-19T01:54:32
|
|
Cleanup legal data
1. The license header is technically not valid if it doesn't have a
copyright signature.
2. The COPYING file has been updated with the different licenses used in
the project.
3. The full GPLv2 header in each file annoys me.
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0b2c4061
|
2011-08-30T23:06:04
|
|
CMakefile: add -Wstrict-aliasing=2 and fix warnings
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
|
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335d6c99
|
2011-05-17T01:46:07
|
|
cache: Drop cuckoo hashing
Now we use a simple closed-addressing cache. Cuckoo hashing was creating
too many issues with race conditions. Fuck that.
Let's see what happens performance wise, we may have to roll back or
come up with another way to implement an efficient multi-threaded cache.
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3de79280
|
2011-05-17T00:51:52
|
|
cache: Fix deadlock
Do not try to adquire the same node lock twice when the cuckoo hashing
resolves to the same node.
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4edf3e09
|
2011-05-15T23:45:24
|
|
Return success code on `git_cache_init`
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|
81201a4c
|
2011-05-15T06:57:34
|
|
Move cache.c to the new error handling
|
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|
3abe3bba
|
2011-05-14T16:05:33
|
|
Move repository.c to the new error handling
|
|
|
99baacfb
|
2011-03-21T19:27:45
|
|
Fix MSVC warnings
|
|
|
72a3fe42
|
2011-03-18T19:38:49
|
|
I broke your bindings
Hey. Apologies in advance -- I broke your bindings.
This is a major commit that includes a long-overdue redesign of the
whole object-database structure. This is expected to be the last major
external API redesign of the library until the first non-alpha release.
Please get your bindings up to date with these changes. They will be
included in the next minor release. Sorry again!
Major features include:
- Real caching and refcounting on parsed objects
- Real caching and refcounting on objects read from the ODB
- Streaming writes & reads from the ODB
- Single-method writes for all object types
- The external API is now partially thread-safe
The speed increases are significant in all aspects, specially when
reading an object several times from the ODB (revwalking) and when
writing big objects to the ODB.
Here's a full changelog for the external API:
blob.h
------
- Remove `git_blob_new`
- Remove `git_blob_set_rawcontent`
- Remove `git_blob_set_rawcontent_fromfile`
- Rename `git_blob_writefile` -> `git_blob_create_fromfile`
- Change `git_blob_create_fromfile`:
The `path` argument is now relative to the repository's working dir
- Add `git_blob_create_frombuffer`
commit.h
--------
- Remove `git_commit_new`
- Remove `git_commit_add_parent`
- Remove `git_commit_set_message`
- Remove `git_commit_set_committer`
- Remove `git_commit_set_author`
- Remove `git_commit_set_tree`
- Add `git_commit_create`
- Add `git_commit_create_v`
- Add `git_commit_create_o`
- Add `git_commit_create_ov`
tag.h
-----
- Remove `git_tag_new`
- Remove `git_tag_set_target`
- Remove `git_tag_set_name`
- Remove `git_tag_set_tagger`
- Remove `git_tag_set_message`
- Add `git_tag_create`
- Add `git_tag_create_o`
tree.h
------
- Change `git_tree_entry_2object`:
New signature is `(git_object **object_out, git_repository *repo, git_tree_entry *entry)`
- Remove `git_tree_new`
- Remove `git_tree_add_entry`
- Remove `git_tree_remove_entry_byindex`
- Remove `git_tree_remove_entry_byname`
- Remove `git_tree_clearentries`
- Remove `git_tree_entry_set_id`
- Remove `git_tree_entry_set_name`
- Remove `git_tree_entry_set_attributes`
object.h
------------
- Remove `git_object_new
- Remove `git_object_write`
- Change `git_object_close`:
This method is now *mandatory*. Not closing an object causes a
memory leak.
odb.h
-----
- Remove type `git_rawobj`
- Remove `git_rawobj_close`
- Rename `git_rawobj_hash` -> `git_odb_hash`
- Change `git_odb_hash`:
New signature is `(git_oid *id, const void *data, size_t len, git_otype type)`
- Add type `git_odb_object`
- Add `git_odb_object_close`
- Change `git_odb_read`:
New signature is `(git_odb_object **out, git_odb *db, const git_oid *id)`
- Change `git_odb_read_header`:
New signature is `(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id)`
- Remove `git_odb_write`
- Add `git_odb_open_wstream`
- Add `git_odb_open_rstream`
odb_backend.h
-------------
- Change type `git_odb_backend`:
New internal signatures are as follows
int (* read)(void **, size_t *, git_otype *, struct git_odb_backend *, const git_oid *)
int (* read_header)(size_t *, git_otype *, struct git_odb_backend *, const git_oid *)
int (* writestream)(struct git_odb_stream **, struct git_odb_backend *, size_t, git_otype)
int (* readstream)( struct git_odb_stream **, struct git_odb_backend *, const git_oid *)
- Add type `git_odb_stream`
- Add enum `git_odb_streammode`
Signed-off-by: Vicent Marti <tanoku@gmail.com>
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|
|
bb3de0c4
|
2011-03-16T21:35:51
|
|
Thread safe cache
|