Author: bdrewery Date: Thu Oct 1 19:17:03 2020 New Revision: 366340 URL: https://svnweb.freebsd.org/changeset/base/366340
Log: Use unlocked page lookup for inmem() to avoid object lock contention Reviewed By: kib, markj Sponsored by: Dell EMC Isilon Submitted by: mlaier Differential Revision: https://reviews.freebsd.org/D26597 Modified: head/sys/kern/vfs_bio.c Modified: head/sys/kern/vfs_bio.c ============================================================================== --- head/sys/kern/vfs_bio.c Thu Oct 1 19:06:07 2020 (r366339) +++ head/sys/kern/vfs_bio.c Thu Oct 1 19:17:03 2020 (r366340) @@ -154,7 +154,7 @@ caddr_t __read_mostly unmapped_buf; /* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */ struct proc *bufdaemonproc; -static int inmem(struct vnode *vp, daddr_t blkno); +static bool inmem(struct vnode *vp, daddr_t blkno); static void vm_hold_free_pages(struct buf *bp, int newbsize); static void vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to); @@ -3586,20 +3586,21 @@ incore(struct bufobj *bo, daddr_t blkno) * it also hunts around in the VM system for the data. */ -static int +static bool inmem(struct vnode * vp, daddr_t blkno) { vm_object_t obj; vm_offset_t toff, tinc, size; - vm_page_t m; + vm_page_t m, n; vm_ooffset_t off; + int valid; ASSERT_VOP_LOCKED(vp, "inmem"); if (incore(&vp->v_bufobj, blkno)) - return 1; + return (1); if (vp->v_mount == NULL) - return 0; + return (0); obj = vp->v_object; if (obj == NULL) return (0); @@ -3609,24 +3610,30 @@ inmem(struct vnode * vp, daddr_t blkno) size = vp->v_mount->mnt_stat.f_iosize; off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; - VM_OBJECT_RLOCK(obj); for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { - m = vm_page_lookup(obj, OFF_TO_IDX(off + toff)); - if (!m) - goto notinmem; + m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); +recheck: + if (m == NULL) + return (0); + /* + * Consider page validity only if page mapping didn't change + * during the check. + */ + valid = vm_page_is_valid(m, + (vm_offset_t)((toff + off) & PAGE_MASK), tinc); + n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff)); + if (m != n) { + m = n; + goto recheck; + } + if (!valid) + return (0); + tinc = size; if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); - if (vm_page_is_valid(m, - (vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0) - goto notinmem; } - VM_OBJECT_RUNLOCK(obj); - return 1; - -notinmem: - VM_OBJECT_RUNLOCK(obj); - return (0); + return (1); } /* _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
