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| author | Gleb Smirnoff <glebius@FreeBSD.org> | 2017-10-09 20:51:58 +0000 |
|---|---|---|
| committer | Gleb Smirnoff <glebius@FreeBSD.org> | 2017-10-09 20:51:58 +0000 |
| commit | 07e87a1d55ffc8cad3be04050b0a6898ccd849ed (patch) | |
| tree | d7a33f518257b4d502c1241ef3d3139dbf9b8a12 /sys/kern/uipc_mbuf.c | |
| parent | e8fd18f306915c411b08ab4664ec0aa3bc03d4d4 (diff) | |
| download | src-07e87a1d55ffc8cad3be04050b0a6898ccd849ed.tar.gz src-07e87a1d55ffc8cad3be04050b0a6898ccd849ed.zip | |
Notes
Diffstat (limited to 'sys/kern/uipc_mbuf.c')
| -rw-r--r-- | sys/kern/uipc_mbuf.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c index 4d4cb3888ee1..a8a0391eae5c 100644 --- a/sys/kern/uipc_mbuf.c +++ b/sys/kern/uipc_mbuf.c @@ -188,7 +188,17 @@ mb_dupcl(struct mbuf *n, struct mbuf *m) KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %p", __func__, m)); KASSERT(!(n->m_flags & M_EXT), ("%s: M_EXT set on %p", __func__, n)); - n->m_ext = m->m_ext; + /* + * Cache access optimization. For most kinds of external + * storage we don't need full copy of m_ext, since the + * holder of the 'ext_count' is responsible to carry the + * free routine and its arguments. Exclusion is EXT_EXTREF, + * where 'ext_cnt' doesn't point into mbuf at all. + */ + if (m->m_ext.ext_type == EXT_EXTREF) + bcopy(&m->m_ext, &n->m_ext, sizeof(struct m_ext)); + else + bcopy(&m->m_ext, &n->m_ext, m_ext_copylen); n->m_flags |= M_EXT; n->m_flags |= m->m_flags & M_RDONLY; |