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[Qemu-devel] [PATCH] Allow adjustment of http block device's readahead s
From: |
Nolan |
Subject: |
[Qemu-devel] [PATCH] Allow adjustment of http block device's readahead size. |
Date: |
Fri, 26 Jun 2009 19:11:24 -0700 |
Allow adjustment of http block device's readahead size, via the
environment variable "HTTP_READAHEAD_SIZE".
Signed-off-by: Nolan Leake <nolan <at> sigbus.net>
diff --git a/block/curl.c b/block/curl.c
index e1a553f..32530eb 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -24,6 +24,7 @@
#include "qemu-common.h"
#include "block_int.h"
#include <curl/curl.h>
+#include <stdlib.h>
// #define DEBUG
// #define DEBUG_VERBOSE
@@ -71,6 +72,7 @@ typedef struct BDRVCURLState {
size_t len;
CURLState states[CURL_NUM_STATES];
char *url;
+ size_t readahead_size;
} BDRVCURLState;
static void curl_clean_state(CURLState *s);
@@ -298,9 +300,21 @@ static int curl_open(BlockDriverState *bs, const char
*filename, int flags)
{
BDRVCURLState *s = bs->opaque;
CURLState *state = NULL;
+ char *readahead;
double d;
static int inited = 0;
+ s->readahead_size = READ_AHEAD_SIZE;
+ readahead = getenv("HTTP_READAHEAD_SIZE");
+ if (readahead) {
+ s->readahead_size = atoi(readahead);
+ }
+ if ((s->readahead_size & 0x1ff) != 0) {
+ fprintf(stderr, "HTTP_READAHEAD_SIZE %Zd not a multiple of 512\n",
+ s->readahead_size);
+ goto out_noclean;
+ }
+
if (!inited) {
curl_global_init(CURL_GLOBAL_ALL);
inited = 1;
@@ -346,6 +360,7 @@ out:
curl_easy_cleanup(state->curl);
state->curl = NULL;
out_noclean:
+ qemu_free(s->url);
return -EINVAL;
}
@@ -401,7 +416,7 @@ static BlockDriverAIOCB *curl_aio_readv(BlockDriverState
*bs,
if (state->orig_buf)
qemu_free(state->orig_buf);
state->buf_start = start;
- state->buf_len = acb->end + READ_AHEAD_SIZE;
+ state->buf_len = acb->end + s->readahead_size;
end = MIN(start + state->buf_len, s->len) - 1;
state->orig_buf = qemu_malloc(state->buf_len);
state->acb[0] = acb;
- [Qemu-devel] [PATCH] Allow adjustment of http block device's readahead size.,
Nolan <=