Date: Sun, 31 Dec 2017 03:15:45 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r327406 - stable/11/sys/fs/tmpfs Message-ID: <201712310315.vBV3FjCO091146@repo.freebsd.org>
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Author: mjg Date: Sun Dec 31 03:15:45 2017 New Revision: 327406 URL: https://svnweb.freebsd.org/changeset/base/327406 Log: MFC r324127: tmpfs: skip zero-sized page count updates Such updates consisted of vast majority of modificiations, especially in tmpfs_reg_resize. For the case where page count did no change and the size grew we only need to update tn_size. Use this fact to avoid vm object lock/relock. Modified: stable/11/sys/fs/tmpfs/tmpfs_subr.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/fs/tmpfs/tmpfs_subr.c ============================================================================== --- stable/11/sys/fs/tmpfs/tmpfs_subr.c Sun Dec 31 03:13:45 2017 (r327405) +++ stable/11/sys/fs/tmpfs/tmpfs_subr.c Sun Dec 31 03:15:45 2017 (r327406) @@ -350,7 +350,8 @@ tmpfs_free_node_locked(struct tmpfs_mount *tmp, struct case VREG: uobj = node->tn_reg.tn_aobj; if (uobj != NULL) { - atomic_subtract_long(&tmp->tm_pages_used, uobj->size); + if (uobj->size != 0) + atomic_subtract_long(&tmp->tm_pages_used, uobj->size); KASSERT((uobj->flags & OBJ_TMPFS) == 0, ("leaked OBJ_TMPFS node %p vm_obj %p", node, uobj)); vm_object_deallocate(uobj); @@ -1375,6 +1376,12 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize, bool oldpages = OFF_TO_IDX(oldsize + PAGE_MASK); MPASS(oldpages == uobj->size); newpages = OFF_TO_IDX(newsize + PAGE_MASK); + + if (__predict_true(newpages == oldpages && newsize >= oldsize)) { + node->tn_size = newsize; + return (0); + } + if (newpages > oldpages && tmpfs_pages_check_avail(tmp, newpages - oldpages) == 0) return (ENOSPC);
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