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Do not map the swap i/o pbufs if the geom provider for the swap

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partition accepts unmapped requests.

Sponsored by:	The FreeBSD Foundation
Tested by:	pho
This commit is contained in:
Konstantin Belousov 2013-03-19 14:39:27 +00:00
parent 6ce697dc73
commit 2cc718a11c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=248514
2 changed files with 34 additions and 13 deletions
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46
sys/vm/swap_pager.c
View File

@ -758,6 +758,17 @@ swp_pager_strategy(struct buf *bp)
TAILQ_FOREACH(sp, &swtailq, sw_list) {
if (bp->b_blkno >= sp->sw_first && bp->b_blkno < sp->sw_end) {
mtx_unlock(&sw_dev_mtx);
if ((sp->sw_flags & SW_UNMAPPED) != 0 &&
unmapped_buf_allowed) {
bp->b_kvaalloc = bp->b_data;
bp->b_data = unmapped_buf;
bp->b_kvabase = unmapped_buf;
bp->b_offset = 0;
bp->b_flags |= B_UNMAPPED;
} else {
pmap_qenter((vm_offset_t)bp->b_data,
&bp->b_pages[0], bp->b_bcount / PAGE_SIZE);
}
sp->sw_strategy(bp, sp);
return;
}
@ -1155,11 +1166,6 @@ swap_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
bp = getpbuf(&nsw_rcount);
bp->b_flags |= B_PAGING;
/*
* map our page(s) into kva for input
*/
pmap_qenter((vm_offset_t)bp->b_data, m + i, j - i);
bp->b_iocmd = BIO_READ;
bp->b_iodone = swp_pager_async_iodone;
bp->b_rcred = crhold(thread0.td_ucred);
@ -1371,8 +1377,6 @@ swap_pager_putpages(vm_object_t object, vm_page_t *m, int count,
bp->b_flags |= B_PAGING;
bp->b_iocmd = BIO_WRITE;
pmap_qenter((vm_offset_t)bp->b_data, &m[i], n);
bp->b_rcred = crhold(thread0.td_ucred);
bp->b_wcred = crhold(thread0.td_ucred);
bp->b_bcount = PAGE_SIZE * n;
@ -1484,7 +1488,12 @@ swp_pager_async_iodone(struct buf *bp)
/*
* remove the mapping for kernel virtual
*/
pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
if ((bp->b_flags & B_UNMAPPED) != 0) {
bp->b_data = bp->b_kvaalloc;
bp->b_kvabase = bp->b_kvaalloc;
bp->b_flags &= ~B_UNMAPPED;
} else
pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
if (bp->b_npages) {
object = bp->b_pages[0]->object;
@ -2144,7 +2153,8 @@ swapon_check_swzone(unsigned long npages)
}
static void
swaponsomething(struct vnode *vp, void *id, u_long nblks, sw_strategy_t *strategy, sw_close_t *close, dev_t dev)
swaponsomething(struct vnode *vp, void *id, u_long nblks,
sw_strategy_t *strategy, sw_close_t *close, dev_t dev, int flags)
{
struct swdevt *sp, *tsp;
swblk_t dvbase;
@ -2180,6 +2190,7 @@ swaponsomething(struct vnode *vp, void *id, u_long nblks, sw_strategy_t *strateg
sp->sw_used = 0;
sp->sw_strategy = strategy;
sp->sw_close = close;
sp->sw_flags = flags;
sp->sw_blist = blist_create(nblks, M_WAITOK);
/*
@ -2537,10 +2548,19 @@ swapgeom_strategy(struct buf *bp, struct swdevt *sp)
bio->bio_caller2 = bp;
bio->bio_cmd = bp->b_iocmd;
bio->bio_data = bp->b_data;
bio->bio_offset = (bp->b_blkno - sp->sw_first) * PAGE_SIZE;
bio->bio_length = bp->b_bcount;
bio->bio_done = swapgeom_done;
if ((bp->b_flags & B_UNMAPPED) != 0) {
bio->bio_ma = bp->b_pages;
bio->bio_data = unmapped_buf;
bio->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK;
bio->bio_ma_n = bp->b_npages;
bio->bio_flags |= BIO_UNMAPPED;
} else {
bio->bio_data = bp->b_data;
bio->bio_ma = NULL;
}
g_io_request(bio, cp);
return;
}
@ -2630,9 +2650,9 @@ swapongeom_ev(void *arg, int flags)
}
nblks = pp->mediasize / DEV_BSIZE;
swaponsomething(swh->vp, cp, nblks, swapgeom_strategy,
swapgeom_close, dev2udev(swh->dev));
swapgeom_close, dev2udev(swh->dev),
(pp->flags & G_PF_ACCEPT_UNMAPPED) != 0 ? SW_UNMAPPED : 0);
swh->error = 0;
return;
}
static int
@ -2721,6 +2741,6 @@ swaponvp(struct thread *td, struct vnode *vp, u_long nblks)
return (error);
swaponsomething(vp, vp, nblks, swapdev_strategy, swapdev_close,
NODEV);
NODEV, 0);
return (0);
}

1
sys/vm/swap_pager.h
View File

@ -68,6 +68,7 @@ struct swdevt {
sw_close_t *sw_close;
};
#define SW_UNMAPPED 0x01
#define SW_CLOSING 0x04
#ifdef _KERNEL