From: Johannes Sixt <j6t@kdbg.org>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
Elijah Newren <newren@gmail.com>, Jeff King <peff@peff.net>
Subject: Re: [PATCH v2] pack-objects: fix performance issues on packing large deltas
Date: Thu, 26 Jul 2018 10:12:40 +0200 [thread overview]
Message-ID: <c872c664-a078-853d-4ce9-631dfd110c94@kdbg.org> (raw)
In-Reply-To: <20180722080421.12887-1-pclouds@gmail.com>
Am 22.07.2018 um 10:04 schrieb Nguyễn Thái Ngọc Duy:
> + if (size < pack->oe_delta_size_limit) {
> + e->delta_size_ = size;
> + e->delta_size_valid = 1;
> + } else {
> + packing_data_lock(pack);
> + if (!pack->delta_size)
> + ALLOC_ARRAY(pack->delta_size, pack->nr_alloc);
> + packing_data_unlock(pack);
> +
> + pack->delta_size[e - pack->objects] = size;
My first thought was that this is wrong (falling prey to the same
mistake as the double-checked locking pattern). But after thinking twice
over it again, I think that this unprotected access of pack->delta_size
is thread-safe.
Of course, I'm assuming that different threads never assign to the same
array index.
> + e->delta_size_valid = 0;
> + }
> }
-- Hannes
prev parent reply other threads:[~2018-07-26 8:12 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 22:51 2.18.0 Regression: packing performance and effectiveness Elijah Newren
2018-07-18 22:51 ` [RFC PATCH] fix-v1: revert "pack-objects: shrink delta_size field in struct object_entry" Elijah Newren
2018-07-18 22:51 ` [RFC PATCH] fix-v2: make OE_DELTA_SIZE_BITS a bit bigger Elijah Newren
2018-07-19 5:41 ` 2.18.0 Regression: packing performance and effectiveness Duy Nguyen
2018-07-19 5:49 ` Jeff King
2018-07-19 15:27 ` Elijah Newren
2018-07-19 15:43 ` Duy Nguyen
2018-07-19 5:44 ` Jeff King
2018-07-19 5:57 ` Duy Nguyen
2018-07-19 15:16 ` Duy Nguyen
2018-07-19 16:42 ` Elijah Newren
2018-07-19 17:23 ` Jeff King
2018-07-19 17:31 ` Duy Nguyen
2018-07-19 18:24 ` Duy Nguyen
2018-07-19 19:17 ` Jeff King
2018-07-19 23:11 ` Elijah Newren
2018-07-20 5:28 ` Jeff King
2018-07-20 5:30 ` Jeff King
2018-07-20 5:47 ` Duy Nguyen
2018-07-20 17:21 ` Elijah Newren
2018-07-19 17:04 ` Jeff King
2018-07-19 19:25 ` Junio C Hamano
2018-07-19 19:27 ` Junio C Hamano
2018-07-20 15:39 ` [PATCH] pack-objects: fix performance issues on packing large deltas Nguyễn Thái Ngọc Duy
2018-07-20 17:40 ` Jeff King
2018-07-21 4:23 ` Duy Nguyen
2018-07-23 21:37 ` Jeff King
2018-07-20 17:43 ` Elijah Newren
2018-07-20 23:52 ` Elijah Newren
2018-07-21 4:07 ` Duy Nguyen
2018-07-21 7:08 ` Duy Nguyen
2018-07-21 4:47 ` Duy Nguyen
2018-07-21 6:56 ` Elijah Newren
2018-07-21 7:14 ` Duy Nguyen
2018-07-22 6:22 ` Elijah Newren
2018-07-22 6:49 ` Duy Nguyen
2018-07-23 12:34 ` Elijah Newren
2018-07-23 15:50 ` Duy Nguyen
2018-07-22 8:04 ` [PATCH v2] " Nguyễn Thái Ngọc Duy
2018-07-23 18:04 ` Junio C Hamano
2018-07-23 18:38 ` Duy Nguyen
2018-07-23 18:49 ` Duy Nguyen
2018-07-23 21:30 ` Jeff King
2018-07-26 8:12 ` Johannes Sixt [this message]
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