Use unlocked page lookup for inmem() to avoid object lock contention
Reviewed By: kib, markj Submitted by: mlaier Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D26653
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31deb3cc76
commit
c2c6fb90e0
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=366594
@ -154,7 +154,6 @@ caddr_t __read_mostly unmapped_buf;
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/* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.c */
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struct proc *bufdaemonproc;
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static int inmem(struct vnode *vp, daddr_t blkno);
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static void vm_hold_free_pages(struct buf *bp, int newbsize);
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static void vm_hold_load_pages(struct buf *bp, vm_offset_t from,
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vm_offset_t to);
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@ -3585,48 +3584,54 @@ incore(struct bufobj *bo, daddr_t blkno)
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* associated VM object. This is like incore except
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* it also hunts around in the VM system for the data.
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*/
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static int
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bool
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inmem(struct vnode * vp, daddr_t blkno)
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{
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vm_object_t obj;
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vm_offset_t toff, tinc, size;
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vm_page_t m;
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vm_page_t m, n;
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vm_ooffset_t off;
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int valid;
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ASSERT_VOP_LOCKED(vp, "inmem");
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if (incore(&vp->v_bufobj, blkno))
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return 1;
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return (true);
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if (vp->v_mount == NULL)
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return 0;
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return (false);
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obj = vp->v_object;
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if (obj == NULL)
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return (0);
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return (false);
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size = PAGE_SIZE;
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if (size > vp->v_mount->mnt_stat.f_iosize)
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size = vp->v_mount->mnt_stat.f_iosize;
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off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize;
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VM_OBJECT_RLOCK(obj);
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for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) {
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m = vm_page_lookup(obj, OFF_TO_IDX(off + toff));
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if (!m)
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goto notinmem;
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m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff));
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recheck:
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if (m == NULL)
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return (false);
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tinc = size;
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if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK))
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tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK);
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if (vm_page_is_valid(m,
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(vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0)
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goto notinmem;
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/*
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* Consider page validity only if page mapping didn't change
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* during the check.
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*/
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valid = vm_page_is_valid(m,
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(vm_offset_t)((toff + off) & PAGE_MASK), tinc);
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n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff));
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if (m != n) {
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m = n;
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goto recheck;
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}
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if (!valid)
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return (false);
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}
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VM_OBJECT_RUNLOCK(obj);
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return 1;
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notinmem:
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VM_OBJECT_RUNLOCK(obj);
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return (0);
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return (true);
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}
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/*
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@ -549,6 +549,7 @@ int vfs_bio_awrite(struct buf *);
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void vfs_busy_pages_acquire(struct buf *bp);
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void vfs_busy_pages_release(struct buf *bp);
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struct buf *incore(struct bufobj *, daddr_t);
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bool inmem(struct vnode *, daddr_t);
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struct buf *gbincore(struct bufobj *, daddr_t);
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struct buf *gbincore_unlocked(struct bufobj *, daddr_t);
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struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
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@ -1697,6 +1697,21 @@ vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
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return (vm_radix_lookup(&object->rtree, pindex));
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}
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/*
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* vm_page_lookup_unlocked:
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*
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* Returns the page associated with the object/offset pair specified;
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* if none is found, NULL is returned. The page may be no longer be
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* present in the object at the time that this function returns. Only
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* useful for opportunistic checks such as inmem().
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*/
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vm_page_t
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vm_page_lookup_unlocked(vm_object_t object, vm_pindex_t pindex)
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{
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return (vm_radix_lookup_unlocked(&object->rtree, pindex));
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}
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/*
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* vm_page_relookup:
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*
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@ -700,6 +700,7 @@ int vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
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void vm_page_invalid(vm_page_t m);
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void vm_page_launder(vm_page_t m);
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vm_page_t vm_page_lookup(vm_object_t, vm_pindex_t);
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vm_page_t vm_page_lookup_unlocked(vm_object_t, vm_pindex_t);
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vm_page_t vm_page_next(vm_page_t m);
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void vm_page_pqbatch_drain(void);
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void vm_page_pqbatch_submit(vm_page_t m, uint8_t queue);
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