From 0a90cab44adb08857ca04962072e773cfa73ad8b Mon Sep 17 00:00:00 2001
From: Deomid Ryabkov <rojer@cesanta.com>
Date: Wed, 21 Mar 2018 22:00:58 +0000
Subject: [PATCH] Improve mbuf allocation behavior
* Limit total amount of headroom, in absolute terms (`MBUF_SIZE_MAX_HEADROOM`).
* If unable to allocate with headroom, fall back to allocating the required minimum.
* For mOS, set default `MBUF_SIZE_MULTIPLIER` to 2 to avoid floating point operations.
Since max headroom size is now capped to 128 bytes, this will not result in much of a bloat.
PUBLISHED_FROM=11d4fc65a46a805bb7c8960f89a3d0b753c58bb8
---
mongoose.c | 17 ++++++++++++++---
mongoose.h | 8 ++++++++
2 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/mongoose.c b/mongoose.c
index 8e7bd8b28..5140a0acb 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -1470,10 +1470,21 @@ size_t mbuf_insert(struct mbuf *a, size_t off, const void *buf, size_t len) {
}
a->len += len;
} else {
- size_t new_size = (size_t)((a->len + len) * MBUF_SIZE_MULTIPLIER);
- if ((p = (char *) MBUF_REALLOC(a->buf, new_size)) != NULL) {
+ size_t min_size = (a->len + len);
+ size_t new_size = (size_t)(min_size * MBUF_SIZE_MULTIPLIER);
+ if (new_size - min_size > MBUF_SIZE_MAX_HEADROOM) {
+ new_size = min_size + MBUF_SIZE_MAX_HEADROOM;
+ }
+ p = (char *) MBUF_REALLOC(a->buf, new_size);
+ if (p == NULL && new_size != min_size) {
+ new_size = min_size;
+ p = (char *) MBUF_REALLOC(a->buf, new_size);
+ }
+ if (p != NULL) {
a->buf = p;
- memmove(a->buf + off + len, a->buf + off, a->len - off);
+ if (off != a->len) {
+ memmove(a->buf + off + len, a->buf + off, a->len - off);
+ }
if (buf != NULL) memcpy(a->buf + off, buf, len);
a->len += len;
a->size = new_size;
diff --git a/mongoose.h b/mongoose.h
index f8030d52a..c668594a5 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -1963,6 +1963,14 @@ extern "C" {
#define MBUF_SIZE_MULTIPLIER 1.5
#endif
+#ifndef MBUF_SIZE_MAX_HEADROOM
+#ifdef BUFSIZ
+#define MBUF_SIZE_MAX_HEADROOM BUFSIZ
+#else
+#define MBUF_SIZE_MAX_HEADROOM 1024
+#endif
+#endif
+
/* Memory buffer descriptor */
struct mbuf {
char *buf; /* Buffer pointer */
--
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