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From: Jameson Miller <jamill@microsoft.com>
To: Jameson Miller <jamill@microsoft.com>
Cc: "git@vger.kernel.org" <git@vger.kernel.org>,
	"gitster@pobox.com" <gitster@pobox.com>,
	"jonathantanmy@google.com" <jonathantanmy@google.com>,
	"pclouds@gmail.com" <pclouds@gmail.com>,
	"peartben@gmail.com" <peartben@gmail.com>,
	"peff@peff.net" <peff@peff.net>,
	"sbeller@google.com" <sbeller@google.com>
Subject: [PATCH v5 4/8] mem-pool: only search head block for available space
Date: Thu, 28 Jun 2018 14:00:10 +0000	[thread overview]
Message-ID: <20180628135932.225288-5-jamill@microsoft.com> (raw)
In-Reply-To: <20180628135932.225288-1-jamill@microsoft.com>

Instead of searching all memory blocks for available space to fulfill
a memory request, only search the head block. If the head block does
not have space, assume that previous block would most likely not be
able to fulfill request either. This could potentially lead to more
memory fragmentation, but also avoids searching memory blocks that
probably will not be able to fulfill request.

This pattern will benefit consumers that are able to generate a good
estimate for how much memory will be needed, or if they are performing
fixed sized allocations, so that once a block is exhausted it will
never be able to fulfill a future request.

The impact of this change on memory was tested by running fast-import on
the git.git and linux.git repositories. The total amount of memory
allocated to the mem-pools did not change with this approach, indicating
that there is not much memory benefit to searching all nodes in the
linked list.

Signed-off-by: Jameson Miller <jamill@microsoft.com>
---
 mem-pool.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mem-pool.c b/mem-pool.c
index 389d7af447..c80124f1fe 100644
--- a/mem-pool.c
+++ b/mem-pool.c
@@ -21,16 +21,16 @@ static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t b
 
 void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
 {
-	struct mp_block *p;
+	struct mp_block *p = NULL;
 	void *r;
 
 	/* round up to a 'uintmax_t' alignment */
 	if (len & (sizeof(uintmax_t) - 1))
 		len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
 
-	for (p = mem_pool->mp_block; p; p = p->next_block)
-		if (p->end - p->next_free >= len)
-			break;
+	if (mem_pool->mp_block &&
+	    mem_pool->mp_block->end - mem_pool->mp_block->next_free >= len)
+		p = mem_pool->mp_block;
 
 	if (!p) {
 		if (len >= (mem_pool->block_alloc / 2)) {
-- 
2.17.1


  parent reply	other threads:[~2018-06-28 14:00 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17 16:34 [PATCH v1 0/5] Allocate cache entries from memory pool Jameson Miller
2018-04-17 16:34 ` Jameson Miller
2018-04-17 16:34 ` [PATCH v1 1/5] read-cache: teach refresh_cache_entry to take istate Jameson Miller
2018-04-17 19:00   ` Ben Peart
2018-04-17 16:34 ` [PATCH v1 2/5] Add an API creating / discarding cache_entry structs Jameson Miller
2018-04-17 23:11   ` Ben Peart
2018-04-17 16:34 ` [PATCH v1 3/5] mem-pool: fill out functionality Jameson Miller
2018-04-20 23:21   ` Jonathan Tan
2018-04-23 17:27     ` Jameson Miller
2018-04-23 17:49       ` Jonathan Tan
2018-04-23 18:20         ` Jameson Miller
2018-04-17 16:34 ` [PATCH v1 4/5] Allocate cache entries from memory pools Jameson Miller
2018-04-17 16:34 ` [PATCH v1 5/5] Add optional memory validations around cache_entry lifecyle Jameson Miller
2018-04-17 18:39 ` [PATCH v1 0/5] Allocate cache entries from memory pool Ben Peart
2018-04-23 14:09   ` Jameson Miller
2018-04-18  4:49 ` Junio C Hamano
2018-04-20 17:49   ` Stefan Beller
2018-04-23 16:44     ` Jameson Miller
2018-04-23 17:18       ` Stefan Beller
2018-04-23 16:19   ` Jameson Miller
2018-04-20 23:34 ` Jonathan Tan
2018-04-23 17:14   ` Jameson Miller
2018-04-30 15:31 ` [PATCH v2 " Jameson Miller
2018-04-30 15:31   ` [PATCH v2 1/5] read-cache: teach refresh_cache_entry() to take istate Jameson Miller
2018-04-30 15:31   ` [PATCH v2 2/5] block alloc: add lifecycle APIs for cache_entry structs Jameson Miller
2018-04-30 15:31   ` [PATCH v2 3/5] mem-pool: fill out functionality Jameson Miller
2018-04-30 21:42     ` Stefan Beller
2018-05-01 15:43       ` Jameson Miller
2018-05-03 16:18     ` Duy Nguyen
2018-04-30 15:31   ` [PATCH v2 4/5] block alloc: allocate cache entries from mem_pool Jameson Miller
2018-04-30 15:31   ` [PATCH v2 5/5] block alloc: add validations around cache_entry lifecyle Jameson Miller
2018-05-03 16:28     ` Duy Nguyen
2018-05-03 16:35   ` [PATCH v2 0/5] Allocate cache entries from memory pool Duy Nguyen
2018-05-03 17:21     ` Stefan Beller
2018-05-03 19:17       ` Duy Nguyen
2018-05-03 20:58         ` Stefan Beller
2018-05-03 21:13           ` Jameson Miller
2018-05-03 22:18             ` [PATCH] alloc.c: replace alloc by mempool Stefan Beller
2018-05-04 16:33               ` Duy Nguyen
2018-05-08  0:37                 ` Junio C Hamano
2018-05-08  0:44                   ` Stefan Beller
2018-05-08  1:07                     ` Junio C Hamano
2018-05-23 14:47 ` [PATCH v3 0/7] allocate cache entries from memory pool Jameson Miller
2018-05-23 14:47   ` [PATCH v3 1/7] read-cache: teach refresh_cache_entry() to take istate Jameson Miller
2018-05-25 22:54     ` Stefan Beller
2018-05-23 14:47   ` [PATCH v3 2/7] block alloc: add lifecycle APIs for cache_entry structs Jameson Miller
2018-05-24  4:52     ` Junio C Hamano
2018-05-24 14:47       ` Jameson Miller
2018-05-23 14:47   ` [PATCH v3 3/7] mem-pool: only search head block for available space Jameson Miller
2018-05-23 14:47   ` [PATCH v3 4/7] mem-pool: add lifecycle management functions Jameson Miller
2018-05-23 14:47   ` [PATCH v3 5/7] mem-pool: fill out functionality Jameson Miller
2018-06-01 19:28     ` Stefan Beller
2018-05-23 14:47   ` [PATCH v3 6/7] block alloc: allocate cache entries from mem_pool Jameson Miller
2018-05-23 14:47   ` [PATCH v3 7/7] block alloc: add validations around cache_entry lifecyle Jameson Miller
2018-05-24  4:55   ` [PATCH v3 0/7] allocate cache entries from memory pool Junio C Hamano
2018-05-24 14:44     ` Jameson Miller
2018-05-25 22:53       ` Stefan Beller
2018-06-20 20:41         ` Jameson Miller
2018-05-25 22:41   ` Stefan Beller
2018-06-20 20:17 ` [PATCH v4 0/8] Allocate cache entries from mem_pool Jameson Miller
2018-06-20 20:17   ` [PATCH v4 1/8] read-cache: teach refresh_cache_entry() to take istate Jameson Miller
2018-06-20 20:17   ` [PATCH v4 2/8] block alloc: add lifecycle APIs for cache_entry structs Jameson Miller
2018-06-21 21:14     ` Stefan Beller
2018-06-28 14:07       ` Jameson Miller
2018-06-20 20:17   ` [PATCH v4 3/8] mem-pool: only search head block for available space Jameson Miller
2018-06-21 21:33     ` Stefan Beller
2018-06-28 14:12       ` Jameson Miller
2018-06-20 20:17   ` [PATCH v4 4/8] mem-pool: tweak math on mp_block allocation size Jameson Miller
2018-06-20 20:17   ` [PATCH v4 5/8] mem-pool: add lifecycle management functions Jameson Miller
2018-06-20 20:17   ` [PATCH v4 6/8] mem-pool: fill out functionality Jameson Miller
2018-06-20 20:17   ` [PATCH v4 7/8] block alloc: allocate cache entries from mem_pool Jameson Miller
2018-06-20 20:17   ` [PATCH v4 8/8] block alloc: add validations around cache_entry lifecyle Jameson Miller
2018-06-28 14:00   ` [PATCH v5 0/8] Allocate cache entries from mem_pool Jameson Miller
2018-06-28 14:00     ` [PATCH v5 1/8] read-cache: teach refresh_cache_entry() to take istate Jameson Miller
2018-06-28 14:00     ` [PATCH v5 2/8] read-cache: make_cache_entry should take object_id struct Jameson Miller
2018-06-28 17:14       ` Junio C Hamano
2018-06-28 22:27       ` SZEDER Gábor
2018-06-28 14:00     ` [PATCH v5 3/8] block alloc: add lifecycle APIs for cache_entry structs Jameson Miller
2018-06-28 18:43       ` Junio C Hamano
2018-06-28 22:28       ` SZEDER Gábor
2018-06-28 14:00     ` Jameson Miller [this message]
2018-06-28 14:00     ` [PATCH v5 5/8] mem-pool: add life cycle management functions Jameson Miller
2018-06-28 17:15       ` Junio C Hamano
2018-06-28 14:00     ` [PATCH v5 6/8] mem-pool: fill out functionality Jameson Miller
2018-06-28 19:09       ` Junio C Hamano
2018-07-02 18:28         ` Jameson Miller
2018-06-28 14:00     ` [PATCH v5 7/8] block alloc: allocate cache entries from mem-pool Jameson Miller
2018-06-28 14:00     ` [PATCH v5 8/8] block alloc: add validations around cache_entry lifecyle Jameson Miller
2018-07-02 19:49     ` [PATCH v6 0/8] Allocate cache entries from mem_pool Jameson Miller
2018-07-02 19:49       ` [PATCH v6 1/8] read-cache: teach refresh_cache_entry to take istate Jameson Miller
2018-07-02 19:49       ` [PATCH v6 2/8] read-cache: teach make_cache_entry to take object_id Jameson Miller
2018-07-02 21:23         ` Stefan Beller
2018-07-05 15:20           ` Jameson Miller
2018-07-02 19:49       ` [PATCH v6 3/8] block alloc: add lifecycle APIs for cache_entry structs Jameson Miller
2018-07-22  9:23         ` Duy Nguyen
2018-07-02 19:49       ` [PATCH v6 4/8] mem-pool: only search head block for available space Jameson Miller
2018-07-02 19:49       ` [PATCH v6 5/8] mem-pool: add life cycle management functions Jameson Miller
2018-07-02 19:49       ` [PATCH v6 6/8] mem-pool: fill out functionality Jameson Miller
2018-07-02 19:49       ` [PATCH v6 7/8] block alloc: allocate cache entries from mem_pool Jameson Miller
2018-07-02 19:49       ` [PATCH v6 8/8] block alloc: add validations around cache_entry lifecyle Jameson Miller

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