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authorglebius <glebius@FreeBSD.org>2014-08-11 12:59:55 +0000
committerglebius <glebius@FreeBSD.org>2014-08-11 12:59:55 +0000
commit22028ff4aa5e9b83aa7c88f71456cf2f60b406e6 (patch)
treeb820d4b27b821cf0b2b136f69b5836bf54254136 /sys/kern/subr_sfbuf.c
parent41f23f3992a9000c140a2012fa3e493a7e75bbbd (diff)
downloadFreeBSD-src-22028ff4aa5e9b83aa7c88f71456cf2f60b406e6.zip
FreeBSD-src-22028ff4aa5e9b83aa7c88f71456cf2f60b406e6.tar.gz
Provide sf_buf_ref() to optimize refcounting of already allocated
sendfile(2) buffers. Sponsored by: Netflix Sponsored by: Nginx, Inc.
Diffstat (limited to 'sys/kern/subr_sfbuf.c')
-rw-r--r--sys/kern/subr_sfbuf.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/sys/kern/subr_sfbuf.c b/sys/kern/subr_sfbuf.c
index e4309d1..1950f69 100644
--- a/sys/kern/subr_sfbuf.c
+++ b/sys/kern/subr_sfbuf.c
@@ -201,6 +201,22 @@ sf_buf_free(struct sf_buf *sf)
mtx_unlock(&sf_buf_lock);
}
+void
+sf_buf_ref(struct sf_buf *sf)
+{
+
+#ifdef SFBUF_OPTIONAL_DIRECT_MAP
+ if (SFBUF_OPTIONAL_DIRECT_MAP)
+ return;
+#endif
+
+ KASSERT(sf->ref_count > 0, ("%s: sf %p not allocated", __func__, sf));
+
+ mtx_lock(&sf_buf_lock);
+ sf->ref_count++;
+ mtx_unlock(&sf_buf_lock);
+}
+
#ifdef SFBUF_PROCESS_PAGE
/*
* Run callback function on sf_buf that holds a certain page.
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