From: Jeff King <peff@peff.net>
To: Derrick Stolee <stolee@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 02/15] pack-bitmap: fix leak of haves/wants object lists
Date: Tue, 18 Feb 2020 15:02:19 -0500 [thread overview]
Message-ID: <20200218200219.GC21774@coredump.intra.peff.net> (raw)
In-Reply-To: <28c2f199-e9eb-4405-9044-92a0af7632ec@gmail.com>
On Tue, Feb 18, 2020 at 12:58:10PM -0500, Derrick Stolee wrote:
> On 2/14/2020 1:22 PM, Jeff King wrote:
> > When we do a bitmap-aware revision traversal, we create an object_list
> > for each of the "haves" and "wants" tips. After creating the result
> > bitmaps these are no longer needed or used, but we never free the list
> > memory.
>
> It's surprising that we got away with this for so long. Is it
> possible that this loop of freeing memory could provide significant
> performance drawbacks? I'm assuming that the free() loop is much
> faster than the malloc() loop, so the impact is negligible.
I don't think it's surprising. We're only talking about leaking hundreds
or perhaps thousands of structs. So maybe a few kilobytes at most. And
we'd typically only run one such bitmap traversal per program.
Meanwhile rev-list is generally storing that same set of objects in a
pending array, and I think we don't generally clean up after it (nor is
there even a convenient function to do so).
So I think it's sort of a drop in the bucket of Git's "eh, this pretty
much lasts about the whole program anyway" leaks. I don't think there's
much performance difference either way in freeing or not. It's mostly
just a cleanliness thing. (I do one day dream of being able to run the
test suite through a leakchecker, but we're still a ways off, I think).
-Peff
next prev parent reply other threads:[~2020-02-18 20:05 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 2:15 [PATCH 0/13] combining object filters and bitmaps Jeff King
2020-02-13 2:16 ` [PATCH 01/13] pack-bitmap: factor out type iterator initialization Jeff King
2020-02-13 17:45 ` Junio C Hamano
2020-02-13 2:16 ` [PATCH 02/13] pack-bitmap: fix leak of haves/wants object lists Jeff King
2020-02-13 18:12 ` Junio C Hamano
2020-02-13 2:17 ` [PATCH 03/13] rev-list: fallback to non-bitmap traversal when filtering Jeff King
2020-02-13 18:19 ` Junio C Hamano
2020-02-13 18:40 ` Jeff King
2020-02-13 2:17 ` [PATCH 04/13] rev-list: consolidate bitmap-disabling options Jeff King
2020-02-13 2:18 ` [PATCH 05/13] rev-list: factor out bitmap-optimized routines Jeff King
2020-02-13 18:34 ` Junio C Hamano
2020-02-13 2:19 ` [PATCH 06/13] rev-list: make --count work with --objects Jeff King
2020-02-13 19:14 ` Junio C Hamano
2020-02-13 20:27 ` Jeff King
2020-02-13 2:20 ` [PATCH 07/13] rev-list: allow bitmaps when counting objects Jeff King
2020-02-13 21:47 ` Junio C Hamano
2020-02-13 22:27 ` Jeff King
2020-02-13 2:20 ` [PATCH 08/13] pack-bitmap: basic noop bitmap filter infrastructure Jeff King
2020-02-13 2:21 ` [PATCH 09/13] rev-list: use bitmap filters for traversal Jeff King
2020-02-13 22:22 ` Junio C Hamano
2020-02-13 22:34 ` Jeff King
2020-02-13 2:21 ` [PATCH 10/13] bitmap: add bitmap_unset() function Jeff King
2020-02-13 2:23 ` [PATCH 11/13] pack-bitmap: implement BLOB_NONE filtering Jeff King
2020-02-13 2:25 ` [PATCH 12/13] pack-bitmap: implement BLOB_LIMIT filtering Jeff King
2020-02-13 23:17 ` Junio C Hamano
2020-02-13 2:25 ` [PATCH 13/13] pack-objects: support filters with bitmaps Jeff King
2020-02-14 18:21 ` [PATCH v2 0/15] combining object filters and bitmaps Jeff King
2020-02-14 18:22 ` [PATCH v2 01/15] pack-bitmap: factor out type iterator initialization Jeff King
2020-02-15 0:10 ` Taylor Blau
2020-02-14 18:22 ` [PATCH v2 02/15] pack-bitmap: fix leak of haves/wants object lists Jeff King
2020-02-15 0:15 ` Taylor Blau
2020-02-15 6:46 ` Jeff King
2020-02-18 17:58 ` Derrick Stolee
2020-02-18 20:02 ` Jeff King [this message]
2020-02-14 18:22 ` [PATCH v2 03/15] rev-list: fallback to non-bitmap traversal when filtering Jeff King
2020-02-15 0:22 ` Taylor Blau
2020-02-14 18:22 ` [PATCH v2 04/15] pack-bitmap: refuse to do a bitmap traversal with pathspecs Jeff King
2020-02-14 19:03 ` Junio C Hamano
2020-02-14 20:51 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 05/15] rev-list: factor out bitmap-optimized routines Jeff King
2020-02-15 0:35 ` Taylor Blau
2020-02-14 18:22 ` [PATCH v2 06/15] rev-list: make --count work with --objects Jeff King
2020-02-15 0:42 ` Taylor Blau
2020-02-15 6:48 ` Jeff King
2020-02-16 23:34 ` Junio C Hamano
2020-02-18 5:24 ` Jeff King
2020-02-18 17:28 ` Junio C Hamano
2020-02-18 19:55 ` Jeff King
2020-02-18 21:19 ` Junio C Hamano
2020-02-18 21:23 ` Jeff King
2020-02-18 18:05 ` Derrick Stolee
2020-02-18 19:59 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 07/15] rev-list: allow bitmaps when counting objects Jeff King
2020-02-15 0:45 ` Taylor Blau
2020-02-15 6:55 ` Jeff King
2020-02-16 23:36 ` Junio C Hamano
2020-02-14 18:22 ` [PATCH v2 08/15] t5310: factor out bitmap traversal comparison Jeff King
2020-02-15 2:14 ` Taylor Blau
2020-02-15 7:00 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 09/15] rev-list: allow commit-only bitmap traversals Jeff King
2020-02-18 18:18 ` Derrick Stolee
2020-02-18 20:05 ` Jeff King
2020-02-18 20:11 ` Derrick Stolee
2020-02-14 18:22 ` [PATCH v2 10/15] pack-bitmap: basic noop bitmap filter infrastructure Jeff King
2020-02-14 18:22 ` [PATCH v2 11/15] rev-list: use bitmap filters for traversal Jeff King
2020-02-14 18:22 ` [PATCH v2 12/15] bitmap: add bitmap_unset() function Jeff King
2020-02-14 18:22 ` [PATCH v2 13/15] pack-bitmap: implement BLOB_NONE filtering Jeff King
2020-02-18 19:26 ` Derrick Stolee
2020-02-18 19:36 ` Derrick Stolee
2020-02-18 20:30 ` Jeff King
2020-02-18 20:24 ` Jeff King
2020-02-14 18:22 ` [PATCH v2 14/15] pack-bitmap: implement BLOB_LIMIT filtering Jeff King
2020-02-14 18:22 ` [PATCH v2 15/15] pack-objects: support filters with bitmaps Jeff King
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