From: andrey.konovalov@linux.dev
To: Marco Elver <elver@google.com>, Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>,
kasan-dev@googlegroups.com, Evgenii Stepanov <eugenis@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v2 13/18] lib/stackdepot: annotate depot_init_pool and depot_alloc_stack
Date: Fri, 10 Feb 2023 22:16:01 +0100 [thread overview]
Message-ID: <f80b02951364e6b40deda965b4003de0cd1a532d.1676063693.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1676063693.git.andreyknvl@google.com>
From: Andrey Konovalov <andreyknvl@google.com>
Clean up the exisiting comments and add new ones to depot_init_pool and
depot_alloc_stack.
As a part of the clean-up, remove mentions of which variable is accessed
by smp_store_release and smp_load_acquire: it is clear as is from the
code.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
lib/stackdepot.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index d4d988276b91..c4bc198c3d93 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -218,32 +218,39 @@ int stack_depot_init(void)
}
EXPORT_SYMBOL_GPL(stack_depot_init);
+/* Uses preallocated memory to initialize a new stack depot pool. */
static void depot_init_pool(void **prealloc)
{
/*
- * This smp_load_acquire() pairs with smp_store_release() to
- * |next_pool_inited| below and in depot_alloc_stack().
+ * smp_load_acquire() here pairs with smp_store_release() below and
+ * in depot_alloc_stack().
*/
if (smp_load_acquire(&next_pool_inited))
return;
+
+ /* Check if the current pool is not yet allocated. */
if (stack_pools[pool_index] == NULL) {
+ /* Use the preallocated memory for the current pool. */
stack_pools[pool_index] = *prealloc;
*prealloc = NULL;
} else {
- /* If this is the last depot pool, do not touch the next one. */
+ /*
+ * Otherwise, use the preallocated memory for the next pool
+ * as long as we do not exceed the maximum number of pools.
+ */
if (pool_index + 1 < DEPOT_MAX_POOLS) {
stack_pools[pool_index + 1] = *prealloc;
*prealloc = NULL;
}
/*
- * This smp_store_release pairs with smp_load_acquire() from
- * |next_pool_inited| above and in stack_depot_save().
+ * This smp_store_release pairs with smp_load_acquire() above
+ * and in stack_depot_save().
*/
smp_store_release(&next_pool_inited, 1);
}
}
-/* Allocation of a new stack in raw storage */
+/* Allocates a new stack in a stack depot pool. */
static struct stack_record *
depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
{
@@ -252,28 +259,35 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
required_size = ALIGN(required_size, 1 << DEPOT_STACK_ALIGN);
+ /* Check if there is not enough space in the current pool. */
if (unlikely(pool_offset + required_size > DEPOT_POOL_SIZE)) {
+ /* Bail out if we reached the pool limit. */
if (unlikely(pool_index + 1 >= DEPOT_MAX_POOLS)) {
WARN_ONCE(1, "Stack depot reached limit capacity");
return NULL;
}
+
+ /* Move on to the next pool. */
pool_index++;
pool_offset = 0;
/*
- * smp_store_release() here pairs with smp_load_acquire() from
- * |next_pool_inited| in stack_depot_save() and
- * depot_init_pool().
+ * smp_store_release() here pairs with smp_load_acquire() in
+ * stack_depot_save() and depot_init_pool().
*/
if (pool_index + 1 < DEPOT_MAX_POOLS)
smp_store_release(&next_pool_inited, 0);
}
+
+ /* Assign the preallocated memory to a pool if required. */
if (*prealloc)
depot_init_pool(prealloc);
+
+ /* Check if we have a pool to save the stack trace. */
if (stack_pools[pool_index] == NULL)
return NULL;
+ /* Save the stack trace. */
stack = stack_pools[pool_index] + pool_offset;
-
stack->hash = hash;
stack->size = size;
stack->handle.pool_index = pool_index;
--
2.25.1
next prev parent reply other threads:[~2023-02-10 21:18 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-10 21:15 [PATCH v2 00/18] lib/stackdepot: fixes and clean-ups andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 01/18] lib/stackdepot: put functions in logical order andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 02/18] lib/stackdepot: use pr_fmt to define message format andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 03/18] lib/stackdepot, mm: rename stack_depot_want_early_init andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 04/18] lib/stackdepot: rename stack_depot_disable andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 05/18] lib/stackdepot: annotate init and early init functions andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 06/18] lib/stackdepot: lower the indentation in stack_depot_init andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 07/18] lib/stackdepot: reorder and annotate global variables andrey.konovalov
2023-02-13 10:33 ` Alexander Potapenko
2023-02-10 21:15 ` [PATCH v2 08/18] lib/stackdepot: rename hash table constants and variables andrey.konovalov
2023-02-13 10:34 ` Alexander Potapenko
2023-02-10 21:15 ` [PATCH v2 09/18] lib/stackdepot: rename slab to pool andrey.konovalov
2023-02-13 10:20 ` Vlastimil Babka
2023-02-13 10:35 ` Alexander Potapenko
2023-02-10 21:15 ` [PATCH v2 10/18] lib/stackdepot: rename handle and pool constants andrey.konovalov
2023-02-10 21:15 ` [PATCH v2 11/18] lib/stackdepot: rename init_stack_pool andrey.konovalov
2023-02-10 21:16 ` [PATCH v2 12/18] lib/stacktrace: drop impossible WARN_ON for depot_init_pool andrey.konovalov
2023-02-13 11:02 ` Alexander Potapenko
2023-02-10 21:16 ` andrey.konovalov [this message]
2023-02-13 11:03 ` [PATCH v2 13/18] lib/stackdepot: annotate depot_init_pool and depot_alloc_stack Alexander Potapenko
2023-02-10 21:16 ` [PATCH v2 14/18] lib/stackdepot: rename next_pool_inited to next_pool_required andrey.konovalov
2023-02-13 11:26 ` Alexander Potapenko
2023-02-10 21:16 ` [PATCH v2 15/18] lib/stacktrace, kasan, kmsan: rework extra_bits interface andrey.konovalov
2023-02-13 11:40 ` Alexander Potapenko
2023-02-10 21:16 ` [PATCH v2 16/18] lib/stackdepot: annotate racy pool_index accesses andrey.konovalov
2023-02-13 11:52 ` Alexander Potapenko
2023-02-10 21:16 ` [PATCH v2 17/18] lib/stackdepot: various comments clean-ups andrey.konovalov
2023-02-13 13:26 ` Alexander Potapenko
2023-02-17 9:46 ` Andrey Konovalov
2023-02-10 21:16 ` [PATCH v2 18/18] lib/stackdepot: move documentation comments to stackdepot.h andrey.konovalov
2023-02-13 13:27 ` Alexander Potapenko
2023-02-17 9:50 ` Andrey Konovalov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f80b02951364e6b40deda965b4003de0cd1a532d.1676063693.git.andreyknvl@google.com \
--to=andrey.konovalov@linux.dev \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@gmail.com \
--cc=andreyknvl@google.com \
--cc=elver@google.com \
--cc=eugenis@google.com \
--cc=glider@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).