From: Jeff King <peff@peff.net>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org, Benjamin Flesch <benjaminflesch@icloud.com>
Subject: Re: [PATCH 9/9] upload-pack: free tree buffers after parsing
Date: Mon, 4 Mar 2024 04:57:36 -0500 [thread overview]
Message-ID: <20240304095736.GA3723539@coredump.intra.peff.net> (raw)
In-Reply-To: <ZeWHdaZnhOHKs5QP@tanuki>
On Mon, Mar 04, 2024 at 09:33:57AM +0100, Patrick Steinhardt wrote:
> > + if (skip_hash && discard_tree &&
> > + (!obj || obj->type == OBJ_TREE) &&
> > + oid_object_info(r, oid, NULL) == OBJ_TREE) {
> > + return &lookup_tree(r, oid)->object;
> > + }
>
> The other condition for blobs does the same, but the condition here
> confuses me. Why do we call `oid_object_info()` if we have already
> figured out that `obj->type == OBJ_TREE`? Feels like wasted effort if
> the in-memory object has been determined to be a tree already anyway.
>
> I'd rather have expected it to look like the following:
>
> if (skip_hash && discard_tree &&
> ((obj && obj->type == OBJ_TREE) ||
> (!obj && oid_object_info(r, oid, NULL)) == OBJ_TREE)) {
> return &lookup_tree(r, oid)->object;
> }
>
> Am I missing some side effect that `oid_object_info()` provides?
Calling oid_object_info() will make sure the on-disk object exists and
has the expected type. Keep in mind that an in-memory "struct object"
may have a type that was just implied by another reference. E.g., if a
commit references some object X in its tree field, then we'll call
lookup_tree(X) to get a "struct tree" without actually touching the odb
at all. When it comes time to parse that object, that's when we'll see
if we really have it and if it's a tree.
In the case of skip_hash (and discard_tree) it might be OK to skip both
of those checks. If we do, I think we should probably do the same for
blobs (in the skip_hash case, we could just return the object we found
already).
But I'd definitely prefer to do that as a separate step (if at all).
-Peff
next prev parent reply other threads:[~2024-03-04 9:57 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-28 22:37 [PATCH 0/9] bound upload-pack memory allocations Jeff King
2024-02-28 22:37 ` [PATCH 1/9] upload-pack: drop separate v2 "haves" array Jeff King
2024-02-28 22:37 ` [PATCH 2/9] upload-pack: switch deepen-not list to an oid_array Jeff King
2024-02-28 22:37 ` [PATCH 3/9] upload-pack: use oidset for deepen_not list Jeff King
2024-02-28 22:38 ` [PATCH 4/9] upload-pack: use a strmap for want-ref lines Jeff King
2024-02-28 22:38 ` [PATCH 5/9] upload-pack: accept only a single packfile-uri line Jeff King
2024-02-28 22:38 ` [PATCH 6/9] upload-pack: disallow object-info capability by default Jeff King
2024-03-04 8:34 ` Patrick Steinhardt
2024-03-04 9:59 ` Jeff King
2024-04-29 20:49 ` Taylor Blau
2024-02-28 22:39 ` [PATCH 7/9] upload-pack: always turn off save_commit_buffer Jeff King
2024-02-28 22:39 ` [PATCH 8/9] upload-pack: use PARSE_OBJECT_SKIP_HASH_CHECK in more places Jeff King
2024-02-28 22:39 ` [PATCH 9/9] upload-pack: free tree buffers after parsing Jeff King
2024-03-04 8:33 ` Patrick Steinhardt
2024-03-04 9:57 ` Jeff King [this message]
2024-03-04 10:00 ` Patrick Steinhardt
2024-02-28 22:47 ` [PATCH 0/9] bound upload-pack memory allocations Junio C Hamano
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