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Merge remote branch 'github/20_chain_realign'

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This commit is contained in:
Nick Mathewson 2010-10-26 21:32:53 -04:00
commit 4f20eeaa09
1 changed files with 19 additions and 8 deletions
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27
buffer.c
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@ -136,6 +136,8 @@ static int use_mmap = 1;
#define CHAIN_PINNED_R(ch) (((ch)->flags & EVBUFFER_MEM_PINNED_R) != 0) #define CHAIN_PINNED_R(ch) (((ch)->flags & EVBUFFER_MEM_PINNED_R) != 0)
static void evbuffer_chain_align(struct evbuffer_chain *chain); static void evbuffer_chain_align(struct evbuffer_chain *chain);
static int evbuffer_chain_should_realign(struct evbuffer_chain *chain,
size_t datalen);
static void evbuffer_deferred_callback(struct deferred_cb *cb, void *arg); static void evbuffer_deferred_callback(struct deferred_cb *cb, void *arg);
static int evbuffer_ptr_memcmp(const struct evbuffer *buf, static int evbuffer_ptr_memcmp(const struct evbuffer *buf,
const struct evbuffer_ptr *pos, const char *mem, size_t len); const struct evbuffer_ptr *pos, const char *mem, size_t len);
@ -1503,7 +1505,8 @@ evbuffer_add(struct evbuffer *buf, const void *data_in, size_t datlen)
buf->total_len += datlen; buf->total_len += datlen;
buf->n_add_for_cb += datlen; buf->n_add_for_cb += datlen;
goto out; goto out;
} else if ((size_t)chain->misalign >= datlen && !CHAIN_PINNED(chain)) { } else if (!CHAIN_PINNED(chain) &&
evbuffer_chain_should_realign(chain, datlen)) {
/* we can fit the data into the misalignment */ /* we can fit the data into the misalignment */
evbuffer_chain_align(chain); evbuffer_chain_align(chain);
@ -1638,6 +1641,17 @@ evbuffer_chain_align(struct evbuffer_chain *chain)
#define MAX_TO_COPY_IN_EXPAND 4096 #define MAX_TO_COPY_IN_EXPAND 4096
#define MAX_TO_REALIGN_IN_EXPAND 2048 #define MAX_TO_REALIGN_IN_EXPAND 2048
/** Helper: return true iff we should realign chain to fit datalen bytes of
data in it. */
static int
evbuffer_chain_should_realign(struct evbuffer_chain *chain,
size_t datlen)
{
return chain->buffer_len - chain->off >= datlen &&
(chain->off < chain->buffer_len / 2) &&
(chain->off <= MAX_TO_REALIGN_IN_EXPAND);
}
/* Expands the available space in the event buffer to at least datlen, all in /* Expands the available space in the event buffer to at least datlen, all in
* a single chunk. Return that chunk. */ * a single chunk. Return that chunk. */
static struct evbuffer_chain * static struct evbuffer_chain *
@ -1680,14 +1694,11 @@ evbuffer_expand_singlechain(struct evbuffer *buf, size_t datlen)
/* If the misalignment plus the remaining space fulfills our data /* If the misalignment plus the remaining space fulfills our data
* needs, we could just force an alignment to happen. Afterwards, we * needs, we could just force an alignment to happen. Afterwards, we
* have enough space. But only do this if we're saving at least 1/2 * have enough space. But only do this if we're saving a lot of space
* the chain size and moving no more than MAX_TO_REALIGN_IN_EXPAND * and not moving too much data. Otherwise the space savings are
* bytes. Otherwise the space savings are probably offset by the time * probably offset by the time lost in copying.
* lost in copying.
*/ */
if (chain->buffer_len - chain->off >= datlen && if (evbuffer_chain_should_realign(chain, datlen)) {
(chain->off < chain->buffer_len / 2) &&
(chain->off <= MAX_TO_REALIGN_IN_EXPAND)) {
evbuffer_chain_align(chain); evbuffer_chain_align(chain);
result = chain; result = chain;
goto ok; goto ok;