diff options
| -rw-r--r-- | sys/kern/vfs_bio.c | 4 | ||||
| -rw-r--r-- | sys/kern/vfs_biomem.c | 97 |
2 files changed, 92 insertions, 9 deletions
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 9eec4c1ec8d..10382832b02 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -1,4 +1,4 @@ -/* $OpenBSD: vfs_bio.c,v 1.173 2016/03/10 03:09:45 beck Exp $ */ +/* $OpenBSD: vfs_bio.c,v 1.174 2016/03/17 03:57:51 beck Exp $ */ /* $NetBSD: vfs_bio.c,v 1.44 1996/06/11 11:15:36 pk Exp $ */ /* @@ -1027,7 +1027,7 @@ buf_get(struct vnode *vp, daddr_t blkno, size_t size) if (size) { buf_alloc_pages(bp, round_page(size)); - SET(bp->b_flags, B_DMA); + KASSERT(ISSET(bp->b_flags, B_DMA)); buf_map(bp); } diff --git a/sys/kern/vfs_biomem.c b/sys/kern/vfs_biomem.c index 16bad75c720..a45cdb71881 100644 --- a/sys/kern/vfs_biomem.c +++ b/sys/kern/vfs_biomem.c @@ -1,7 +1,8 @@ -/* $OpenBSD: vfs_biomem.c,v 1.34 2015/07/19 21:21:14 beck Exp $ */ +/* $OpenBSD: vfs_biomem.c,v 1.35 2016/03/17 03:57:51 beck Exp $ */ /* * Copyright (c) 2007 Artur Grabowski <art@openbsd.org> + * Copyright (c) 2012-2016 Bob Beck <beck@openbsd.org> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above @@ -222,7 +223,7 @@ buf_dealloc_mem(struct buf *bp) } /* - * Only used by bread_cluster. + * Only used by bread_cluster. */ void buf_fix_mapping(struct buf *bp, vsize_t newsize) @@ -267,6 +268,7 @@ void buf_alloc_pages(struct buf *bp, vsize_t size) { voff_t offs; + int i; KASSERT(size == round_page(size)); KASSERT(bp->b_pobj == NULL); @@ -278,8 +280,27 @@ buf_alloc_pages(struct buf *bp, vsize_t size) KASSERT(buf_page_offset > 0); - (void) uvm_pagealloc_multi(buf_object, offs, size, UVM_PLA_WAITOK); + /* + * Attempt to allocate with NOWAIT. if we can't, then throw + * away some clean pages and try again. Finally, if that + * fails, do a WAITOK allocation so the page daemon can find + * memory for us. + */ + do { + i = uvm_pagealloc_multi(buf_object, offs, size, + UVM_PLA_NOWAIT); + if (i == 0) + break; + } while (bufbackoff(&dma_constraint, 100) == 0); + if (i != 0) + i = uvm_pagealloc_multi(buf_object, offs, size, + UVM_PLA_WAITOK); + /* should not happen */ + if (i != 0) + panic("uvm_pagealloc_multi unable to allocate an buf_object of size %lu", size); bcstats.numbufpages += atop(size); + bcstats.dmapages += atop(size); + SET(bp->b_flags, B_DMA); bp->b_pobj = buf_object; bp->b_poffs = offs; bp->b_bufsize = size; @@ -307,10 +328,72 @@ buf_free_pages(struct buf *bp) pg->wire_count = 0; uvm_pagefree(pg); bcstats.numbufpages--; + if (ISSET(bp->b_flags, B_DMA)) + bcstats.dmapages--; } + CLR(bp->b_flags, B_DMA); } -/* - * XXX - it might make sense to make a buf_realloc_pages to avoid - * bouncing through the free list all the time. - */ +/* Reallocate a buf into a particular pmem range specified by "where". */ +int +buf_realloc_pages(struct buf *bp, struct uvm_constraint_range *where, + int flags) +{ + vaddr_t va; + int dma; + int i, r; + KASSERT(!(flags & UVM_PLA_WAITOK) ^ !(flags & UVM_PLA_NOWAIT)); + + splassert(IPL_BIO); + KASSERT(ISSET(bp->b_flags, B_BUSY)); + dma = ISSET(bp->b_flags, B_DMA); + + /* if the original buf is mapped, unmap it */ + if (bp->b_data != NULL) { + va = (vaddr_t)bp->b_data; + pmap_kremove(va, bp->b_bufsize); + pmap_update(pmap_kernel()); + } + + do { + r = uvm_pagerealloc_multi(bp->b_pobj, bp->b_poffs, + bp->b_bufsize, UVM_PLA_NOWAIT, where); + if (r == 0) + break; + } while ((bufbackoff(where, 100) == 0) && (flags & UVM_PLA_WAITOK)); + if (r != 0 && (! flags & UVM_PLA_NOWAIT)) + r = uvm_pagerealloc_multi(bp->b_pobj, bp->b_poffs, + bp->b_bufsize, flags, where); + + /* + * If the allocation has succeeded, we may be somewhere different. + * If the allocation has failed, we are in the same place. + * + * We still have to re-map the buffer before returning. + */ + + /* take it out of dma stats until we know where we are */ + if (dma) + bcstats.dmapages -= atop(bp->b_bufsize); + + dma = 1; + /* if the original buf was mapped, re-map it */ + for (i = 0; i < atop(bp->b_bufsize); i++) { + struct vm_page *pg = uvm_pagelookup(bp->b_pobj, + bp->b_poffs + ptoa(i)); + KASSERT(pg != NULL); + if (!PADDR_IS_DMA_REACHABLE(VM_PAGE_TO_PHYS(pg))) + dma = 0; + if (bp->b_data != NULL) { + pmap_kenter_pa(va + ptoa(i), VM_PAGE_TO_PHYS(pg), + PROT_READ|PROT_WRITE); + pmap_update(pmap_kernel()); + } + } + if (dma) { + SET(bp->b_flags, B_DMA); + bcstats.dmapages += atop(bp->b_bufsize); + } else + CLR(bp->b_flags, B_DMA); + return(r); +} |