> On 1. Oct 2020, at 21:17, Bryan Drewery <bdrew...@freebsd.org> wrote: > > 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)); Where is vm_page_lookup_unlocked() defined? For me, this breaks kernel compilation...
Best regards
Michael
> + 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);
> }
>
> /*
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