Date: Sun, 23 Dec 2012 22:43:27 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r244643 - in head/sys: fs/devfs kern sys Message-ID: <201212232243.qBNMhRFt081673@svn.freebsd.org>
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Author: kib Date: Sun Dec 23 22:43:27 2012 New Revision: 244643 URL: http://svnweb.freebsd.org/changeset/base/244643 Log: Do not force a writer to the devfs file to drain the buffer writes. Requested and tested by: Ian Lepore <freebsd@damnhippie.dyndns.org> MFC after: 2 weeks Modified: head/sys/fs/devfs/devfs_vnops.c head/sys/kern/sys_generic.c head/sys/sys/file.h Modified: head/sys/fs/devfs/devfs_vnops.c ============================================================================== --- head/sys/fs/devfs/devfs_vnops.c Sun Dec 23 22:41:54 2012 (r244642) +++ head/sys/fs/devfs/devfs_vnops.c Sun Dec 23 22:43:27 2012 (r244643) @@ -1049,6 +1049,7 @@ devfs_open(struct vop_open_args *ap) int error, ref, vlocked; struct cdevsw *dsw; struct file *fpop; + struct mtx *mtxp; if (vp->v_type == VBLK) return (ENXIO); @@ -1099,6 +1100,16 @@ devfs_open(struct vop_open_args *ap) #endif if (fp->f_ops == &badfileops) finit(fp, fp->f_flag, DTYPE_VNODE, dev, &devfs_ops_f); + mtxp = mtx_pool_find(mtxpool_sleep, fp); + + /* + * Hint to the dofilewrite() to not force the buffer draining + * on the writer to the file. Most likely, the write would + * not need normal buffers. + */ + mtx_lock(mtxp); + fp->f_vnread_flags |= FDEVFS_VNODE; + mtx_unlock(mtxp); return (error); } Modified: head/sys/kern/sys_generic.c ============================================================================== --- head/sys/kern/sys_generic.c Sun Dec 23 22:41:54 2012 (r244642) +++ head/sys/kern/sys_generic.c Sun Dec 23 22:43:27 2012 (r244643) @@ -536,7 +536,8 @@ dofilewrite(td, fd, fp, auio, offset, fl ktruio = cloneuio(auio); #endif cnt = auio->uio_resid; - if (fp->f_type == DTYPE_VNODE) + if (fp->f_type == DTYPE_VNODE && + (fp->f_vnread_flags & FDEVFS_VNODE) == 0) bwillwrite(); if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) { if (auio->uio_resid != cnt && (error == ERESTART || Modified: head/sys/sys/file.h ============================================================================== --- head/sys/sys/file.h Sun Dec 23 22:41:54 2012 (r244642) +++ head/sys/sys/file.h Sun Dec 23 22:43:27 2012 (r244643) @@ -178,7 +178,8 @@ struct file { #define f_advice f_vnun.fvn_advice #define FOFFSET_LOCKED 0x1 -#define FOFFSET_LOCK_WAITING 0x2 +#define FOFFSET_LOCK_WAITING 0x2 +#define FDEVFS_VNODE 0x4 #endif /* _KERNEL || _WANT_FILE */
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