From: Eric Wong <e@80x24.org>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>
Subject: [PATCH v2] delta-islands: free island-related data after use
Date: Thu, 17 Nov 2022 23:06:58 +0000 [thread overview]
Message-ID: <20221117230658.M516129@dcvr> (raw)
In-Reply-To: <221116.861qq2kieu.gmgdl@evledraar.gmail.com>
Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:
> On Wed, Nov 16 2022, Eric Wong wrote:
> > Memory savings were measured using the following patch which
> > relies on a patched LD_PRELOAD-based malloc debugger:
> > https://80x24.org/spew/20221116095404.3974691-1-e@80x24.org/raw
>
> FWIW SANITIZE=leak will find this if you stick a "remote_islands = NULL"
> and run e.g. t5320-delta-islands.sh, but maybe you needed this closer to
> production.
>
> Valgrind will also work, but of course be *much* slower.
Yeah, I run that LD_PRELOAD thing in production since it's
cheap compared to valgrind.
> Perfect shouldn't be the enemy of the good & all that, but in this case
> it's not too much more effort to just give this data an appropriate
> lifetime instead of the global, I tried that out for just the "regex"
> part of this below.
>
> The free_remote_islands() seems to be similarly alive between
> "find_island_for_ref" and "deduplicate_islands".
>
> Your version also works, but the root cause of this sort of thing is
> these global lifetimes, which sometimes we do for a good reason, but in
> this case we don't.
Agreed on all points. Overall, the amount of globals in git has
long seemed excessive and offputting to me (and likely other
drive-by hackers).
> diff --git a/delta-islands.c b/delta-islands.c
> index 26f9e99e1a9..ef86a91059c 100644
> --- a/delta-islands.c
> +++ b/delta-islands.c
> @@ -312,29 +312,41 @@ void resolve_tree_islands(struct repository *r,
> free(todo);
> }
>
> -static regex_t *island_regexes;
> -static unsigned int island_regexes_alloc, island_regexes_nr;
> +struct island_config_data {
> + regex_t *rx;
> + size_t nr;
> + size_t alloc;
> +};
I've added kh_str_t *remote_islands and renamed
s/island_config_data/island_load_data/ in the below version
to reflect the slightly different scope of remote_islands.
> static const char *core_island_name;
>
> -static int island_config_callback(const char *k, const char *v, void *cb UNUSED)
> +static void island_config_data_release(struct island_config_data *icd)
> +{
> + for (size_t i = 0; i < icd->nr; i++)
> + regfree(&icd->rx[i]);
> + free(icd->rx);
> +}
icd => ild since config => load
> +static int island_config_callback(const char *k, const char *v, void *cb)
> {
> + struct island_config_data *data = cb;
> +
data => ild
I don't like the name `data' for a typed variable.
Aside from that, v2 below still frees the regex memory early on
in the hopes deduplicate_islands() can reuse some of the freed
regexp memory.
Anyways, here's v2, which seems to work. I'm still trying to
figure out SATA errors+resets after replacing a CMOS battery,
but I really hope this patch isn't the cause.
-----8<-----
From: Eric Wong <e@80x24.org>
Subject: [PATCH] delta-islands: free island-related data after use
On my use case involving 771 islands of Linux on kernel.org,
this reduces memory usage by around 25MB. The bulk of that
comes from free_remote_islands, since free_config_regexes only
saves around 40k.
This memory is saved early in the memory-intensive pack process,
making it available for the remainder of the long process.
Signed-off-by: Eric Wong <e@80x24.org>
Co-authored-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
v2: reduce scope of load-time data structures with hints from Ævar
delta-islands.c | 71 +++++++++++++++++++++++++++++++++++--------------
1 file changed, 51 insertions(+), 20 deletions(-)
diff --git a/delta-islands.c b/delta-islands.c
index 26f9e99e1a..90c0d6958f 100644
--- a/delta-islands.c
+++ b/delta-islands.c
@@ -26,8 +26,6 @@ static kh_oid_map_t *island_marks;
static unsigned island_counter;
static unsigned island_counter_core;
-static kh_str_t *remote_islands;
-
struct remote_island {
uint64_t hash;
struct oid_array oids;
@@ -312,29 +310,55 @@ void resolve_tree_islands(struct repository *r,
free(todo);
}
-static regex_t *island_regexes;
-static unsigned int island_regexes_alloc, island_regexes_nr;
+struct island_load_data {
+ kh_str_t *remote_islands;
+ regex_t *rx;
+ size_t nr;
+ size_t alloc;
+};
static const char *core_island_name;
-static int island_config_callback(const char *k, const char *v, void *cb UNUSED)
+static void free_config_regexes(struct island_load_data *ild)
{
+ for (size_t i = 0; i < ild->nr; i++)
+ regfree(&ild->rx[i]);
+ free(ild->rx);
+}
+
+static void free_remote_islands(kh_str_t *remote_islands)
+{
+ const char *island_name;
+ struct remote_island *rl;
+
+ kh_foreach(remote_islands, island_name, rl, {
+ free((void *)island_name);
+ oid_array_clear(&rl->oids);
+ free(rl);
+ });
+ kh_destroy_str(remote_islands);
+}
+
+static int island_config_callback(const char *k, const char *v, void *cb)
+{
+ struct island_load_data *ild = cb;
+
if (!strcmp(k, "pack.island")) {
struct strbuf re = STRBUF_INIT;
if (!v)
return config_error_nonbool(k);
- ALLOC_GROW(island_regexes, island_regexes_nr + 1, island_regexes_alloc);
+ ALLOC_GROW(ild->rx, ild->nr + 1, ild->alloc);
if (*v != '^')
strbuf_addch(&re, '^');
strbuf_addstr(&re, v);
- if (regcomp(&island_regexes[island_regexes_nr], re.buf, REG_EXTENDED))
+ if (regcomp(&ild->rx[ild->nr], re.buf, REG_EXTENDED))
die(_("failed to load island regex for '%s': %s"), k, re.buf);
strbuf_release(&re);
- island_regexes_nr++;
+ ild->nr++;
return 0;
}
@@ -344,7 +368,8 @@ static int island_config_callback(const char *k, const char *v, void *cb UNUSED)
return 0;
}
-static void add_ref_to_island(const char *island_name, const struct object_id *oid)
+static void add_ref_to_island(kh_str_t *remote_islands, const char *island_name,
+ const struct object_id *oid)
{
uint64_t sha_core;
struct remote_island *rl = NULL;
@@ -365,8 +390,10 @@ static void add_ref_to_island(const char *island_name, const struct object_id *o
}
static int find_island_for_ref(const char *refname, const struct object_id *oid,
- int flags UNUSED, void *data UNUSED)
+ int flags UNUSED, void *cb)
{
+ struct island_load_data *ild = cb;
+
/*
* We should advertise 'ARRAY_SIZE(matches) - 2' as the max,
* so we can diagnose below a config with more capture groups
@@ -377,8 +404,8 @@ static int find_island_for_ref(const char *refname, const struct object_id *oid,
struct strbuf island_name = STRBUF_INIT;
/* walk backwards to get last-one-wins ordering */
- for (i = island_regexes_nr - 1; i >= 0; i--) {
- if (!regexec(&island_regexes[i], refname,
+ for (i = ild->nr - 1; i >= 0; i--) {
+ if (!regexec(&ild->rx[i], refname,
ARRAY_SIZE(matches), matches, 0))
break;
}
@@ -403,12 +430,12 @@ static int find_island_for_ref(const char *refname, const struct object_id *oid,
strbuf_add(&island_name, refname + match->rm_so, match->rm_eo - match->rm_so);
}
- add_ref_to_island(island_name.buf, oid);
+ add_ref_to_island(ild->remote_islands, island_name.buf, oid);
strbuf_release(&island_name);
return 0;
}
-static struct remote_island *get_core_island(void)
+static struct remote_island *get_core_island(kh_str_t *remote_islands)
{
if (core_island_name) {
khiter_t pos = kh_get_str(remote_islands, core_island_name);
@@ -419,7 +446,7 @@ static struct remote_island *get_core_island(void)
return NULL;
}
-static void deduplicate_islands(struct repository *r)
+static void deduplicate_islands(kh_str_t *remote_islands, struct repository *r)
{
struct remote_island *island, *core = NULL, **list;
unsigned int island_count, dst, src, ref, i = 0;
@@ -445,7 +472,7 @@ static void deduplicate_islands(struct repository *r)
}
island_bitmap_size = (island_count / 32) + 1;
- core = get_core_island();
+ core = get_core_island(remote_islands);
for (i = 0; i < island_count; ++i) {
mark_remote_island_1(r, list[i], core && list[i]->hash == core->hash);
@@ -456,12 +483,16 @@ static void deduplicate_islands(struct repository *r)
void load_delta_islands(struct repository *r, int progress)
{
+ struct island_load_data ild = { 0 };
+
island_marks = kh_init_oid_map();
- remote_islands = kh_init_str();
- git_config(island_config_callback, NULL);
- for_each_ref(find_island_for_ref, NULL);
- deduplicate_islands(r);
+ git_config(island_config_callback, &ild);
+ ild.remote_islands = kh_init_str();
+ for_each_ref(find_island_for_ref, &ild);
+ free_config_regexes(&ild);
+ deduplicate_islands(ild.remote_islands, r);
+ free_remote_islands(ild.remote_islands);
if (progress)
fprintf(stderr, _("Marked %d islands, done.\n"), island_counter);
next prev parent reply other threads:[~2022-11-17 23:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 10:50 [PATCH] delta-islands: free island-related data after use Eric Wong
2022-11-16 15:44 ` Ævar Arnfjörð Bjarmason
2022-11-17 23:06 ` Eric Wong [this message]
2022-11-18 1:51 ` [PATCH v2] " Ævar Arnfjörð Bjarmason
2022-11-22 20:22 ` Jeff King
2022-11-16 18:44 ` [PATCH] " Jeff King
2023-02-01 9:20 ` pack-objects memory use observations [was: [PATCH] delta-islands: free island-related data after use] Eric Wong
2023-02-01 22:09 ` Eric Wong
2023-02-02 0:11 ` Jeff King
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