user/sven/git.git/tree.c, branch v1.4.4.4

Convert memcpy(a,b,20) to hashcpy(a,b).

2006-08-23T20:53:10Z

This abstracts away the size of the hash values when copying them from memory location to memory location, much as the introduction of hashcmp abstracted away hash value comparsion. A few call sites were using char* rather than unsigned char* so I added the cast rather than open hashcpy to be void*. This is a reasonable tradeoff as most call sites already use unsigned char* and the existing hashcmp is also declared to be unsigned char*. [jc: Splitted the patch to "master" part, to be followed by a patch for merge-recursive.c which is not in "master" yet. Fixed the cast in the latter hunk to combine-diff.c which was wrong in the original. Also converted ones left-over in combine-diff.c, diff-lib.c and upload-pack.c ] Signed-off-by: Shawn O. Pearce Signed-off-by: Junio C Hamano

Make track_tree_refs void.

2006-08-15T01:59:03Z

Signed-off-by: David Rientjes Signed-off-by: Junio C Hamano

Remove TYPE_* constant macros and use object_type enums consistently.

2006-07-13T06:18:03Z

This updates the type-enumeration constants introduced to reduce the memory footprint of "struct object" to match the type bits already used in the packfile format, by removing the former (i.e. TYPE_* constant macros) and using the latter (i.e. enum object_type) throughout the code for consistency. Eventually we can stop passing around the "type strings" entirely, and this will help - no confusion about two different integer enumeration. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Add specialized object allocator

2006-06-20T01:42:21Z

This creates a simple specialized object allocator for basic objects. This avoids wasting space with malloc overhead (metadata and extra alignment), since the specialized allocator knows the alignment, and that objects, once allocated, are never freed. It also allows us to track some basic statistics about object allocations. For example, for the mozilla import, it shows object usage as follows: blobs: 627629 (14710 kB) trees: 1119035 (34969 kB) commits: 196423 (8440 kB) tags: 1336 (46 kB) and the simpler allocator shaves off about 2.5% off the memory footprint off a "git-rev-list --all --objects", and is a bit faster too. [ Side note: this concludes the series of "save memory in object storage". The thing is, there simply isn't much more to be saved on the objects. Doing "git-rev-list --all --objects" on the mozilla archive has a final total RSS of 131498 pages for me: that's about 513MB. Of that, the object overhead is now just 56MB, the rest is going somewhere else (put another way: the fact that this patch shaves off 2.5% of the total memory overhead, considering that objects are now not much more than 10% of the total shows how big the wasted space really was: this makes object allocations much more memory- and time-efficient). I haven't looked at where the rest is, but I suspect the bulk of it is just the pack-file loading. It may be that we should pack the tree objects separately from the blob objects: for git-rev-list --objects, we don't actually ever need to even look at the blobs, but since trees and blobs are interspersed in the pack-file, we end up not being dense in the tree accesses, so we end up looking at more pages than we strictly need to. So with a 535MB pack-file, it's entirely possible - even likely - that most of the remaining RSS is just the mmap of the pack-file itself. We don't need to map in _all_ of it, but we do end up mapping a fair amount. ] Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Shrink "struct object" a bit

2006-06-18T01:49:18Z

This shrinks "struct object" by a small amount, by getting rid of the "struct type *" pointer and replacing it with a 3-bit bitfield instead. In addition, we merge the bitfields and the "flags" field, which incidentally should also remove a useless 4-byte padding from the object when in 64-bit mode. Now, our "struct object" is still too damn large, but it's now less obviously bloated, and of the remaining fields, only the "util" (which is not used by most things) is clearly something that should be eventually discarded. This shrinks the "git-rev-list --all" memory use by about 2.5% on the kernel archive (and, perhaps more importantly, on the larger mozilla archive). That may not sound like much, but I suspect it's more on a 64-bit platform. There are other remaining inefficiencies (the parent lists, for example, probably have horrible malloc overhead), but this was pretty obvious. Most of the patch is just changing the comparison of the "type" pointer from one of the constant string pointers to the appropriate new TYPE_xxx small integer constant. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

tree_entry(): new tree-walking helper function

2006-05-31T06:03:01Z

This adds a "tree_entry()" function that combines the common operation of doing a "tree_entry_extract()" + "update_tree_entry()". It also has a simplified calling convention, designed for simple loops that traverse over a whole tree: the arguments are pointers to the tree descriptor and a name_entry structure to fill in, and it returns a boolean "true" if there was an entry left to be gotten in the tree. This allows tree traversal with struct tree_desc desc; struct name_entry entry; desc.buf = tree->buffer; desc.size = tree->size; while (tree_entry(&desc, &entry) { ... use "entry.{path, sha1, mode, pathlen}" ... } which is not only shorter than writing it out in full, it's hopefully less error prone too. [ It's actually a tad faster too - we don't need to recalculate the entry pathlength in both extract and update, but need to do it only once. Also, some callers can avoid doing a "strlen()" on the result, since it's returned as part of the name_entry structure. However, by now we're talking just 1% speedup on "git-rev-list --objects --all", and we're definitely at the point where tree walking is no longer the issue any more. ] NOTE! Not everybody wants to use this new helper function, since some of the tree walkers very much on purpose do the descriptor update separately from the entry extraction. So the "extract + update" sequence still remains as the core sequence, this is just a simplified interface. We should probably add a silly two-line inline helper function for initializing the descriptor from the "struct tree" too, just to cut down on the noise from that common "desc" initializer. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Remove last vestiges of generic tree_entry_list

2006-05-30T02:08:37Z

The old tree_entry_list is dead, long live the unified single tree parser. Yes, we now still have a compatibility function to create a bogus tree_entry_list in builtin-read-tree.c, but that is now entirely local to that very messy piece of code. I'd love to clean read-tree.c up too, but I'm too scared right now, so the best I can do is to just contain the damage, and try to make sure that no new users of the tree_entry_list sprout up by not having it as an exported interface any more. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Remove unused "zeropad" entry from tree_list_entry

2006-05-30T02:08:25Z

That was a hack, only needed because 'git fsck-objects' didn't look at the raw tree format. Now that fsck traverses the tree itself, we can drop it. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Remove "tree->entries" tree-entry list from tree parser

2006-05-30T02:06:59Z

Instead, just use the tree buffer directly, and use the tree-walk infrastructure to walk the buffers instead of the tree-entry list. The tree-entry list is inefficient, and generates tons of small allocations for no good reason. The tree-walk infrastructure is generally no harder to use than following a linked list, and allows us to do most tree parsing in-place. Some programs still use the old tree-entry lists, and are a bit painful to convert without major surgery. For them we have a helper function that creates a temporary tree-entry list on demand. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Switch "read_tree_recursive()" over to tree-walk functionality

2006-05-30T02:05:11Z

Don't use the tree_entry list any more. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano