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authorSebastian Andrzej Siewior2014-01-18 21:24:58 +0100
committerJason A. Donenfeld2014-01-19 15:08:49 +0100
commitd3581b58890389794de5d5222c91a0129873e95c (patch)
tree95c4010b61869934cca86c5ac23056463754f2ee
parentea7210bef377be4ffb088a1a8e5a9dd354f82afb (diff)
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cache: use sendfile() instead of a pair of read() + write()
sendfile() does the same job and avoids to copy the content into userland and back. One has to define NO_SENDFILE in case the OS (kernel / libc) does not supported. It is disabled by default on non-linux environemnts. According to the glibc, sendfile64() was added in Linux 2.4 (so it has been there for a while) but after browsing over the mapage of FreeBSD's I noticed that the prototype is little different. Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
-rw-r--r--Makefile1
-rw-r--r--cache.c26
-rw-r--r--cgit.mk8
3 files changed, 34 insertions, 1 deletions
diff --git a/Makefile b/Makefile
index 2dc92df..05b97d7 100644
--- a/Makefile
+++ b/Makefile
@@ -29,6 +29,7 @@ DOC_PDF = $(patsubst %.txt,%.pdf,$(MAN_TXT))
# j, z, t. (representing long long int, char, intmax_t, size_t, ptrdiff_t).
# some C compilers supported these specifiers prior to C99 as an extension.
#
+# Define HAVE_LINUX_SENDFILE to use sendfile()
#-include config.mak
diff --git a/cache.c b/cache.c
index fcd461f..9e7eeb0 100644
--- a/cache.c
+++ b/cache.c
@@ -13,6 +13,9 @@
*
*/
+#ifdef HAVE_LINUX_SENDFILE
+#include <sys/sendfile.h>
+#endif
#include "cgit.h"
#include "cache.h"
#include "html.h"
@@ -30,7 +33,6 @@ struct cache_slot {
const char *lock_name;
int match;
struct stat cache_st;
- struct stat lock_st;
int bufsize;
char buf[CACHE_BUFSIZE];
};
@@ -81,6 +83,23 @@ static int close_slot(struct cache_slot *slot)
/* Print the content of the active cache slot (but skip the key). */
static int print_slot(struct cache_slot *slot)
{
+#ifdef HAVE_LINUX_SENDFILE
+ off_t start_off;
+ int ret;
+
+ start_off = slot->keylen + 1;
+
+ do {
+ ret = sendfile(STDOUT_FILENO, slot->cache_fd, &start_off,
+ slot->cache_st.st_size - start_off);
+ if (ret < 0) {
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+ return errno;
+ }
+ return 0;
+ } while (1);
+#else
ssize_t i, j;
i = lseek(slot->cache_fd, slot->keylen + 1, SEEK_SET);
@@ -97,6 +116,7 @@ static int print_slot(struct cache_slot *slot)
return errno;
else
return 0;
+#endif
}
/* Check if the slot has expired */
@@ -188,6 +208,10 @@ static int fill_slot(struct cache_slot *slot)
/* Generate cache content */
slot->fn();
+ /* update stat info */
+ if (fstat(slot->lock_fd, &slot->cache_st))
+ return errno;
+
/* Restore stdout */
if (dup2(tmp, STDOUT_FILENO) == -1)
return errno;
diff --git a/cgit.mk b/cgit.mk
index 056c3f9..3b8b79a 100644
--- a/cgit.mk
+++ b/cgit.mk
@@ -68,6 +68,14 @@ ifeq ($(findstring BSD,$(uname_S)),)
CGIT_LIBS += -ldl
endif
+# glibc 2.1+ offers sendfile which the most common C library on Linux
+ifeq ($(uname_S),Linux)
+ HAVE_LINUX_SENDFILE = YesPlease
+endif
+
+ifdef HAVE_LINUX_SENDFILE
+ CGIT_CFLAGS += -DHAVE_LINUX_SENDFILE
+endif
CGIT_OBJ_NAMES += cgit.o
CGIT_OBJ_NAMES += cache.o