int uvm_loanbreak_anon(struct vm_anon *anon, struct uvm_object *uobj) { struct vm_page *pg; KASSERT(mutex_owned(anon->an_lock)); KASSERT(uobj == NULL || mutex_owned(uobj->vmobjlock)); /* get new un-owned replacement page */ pg = uvm_pagealloc(NULL, 0, NULL, 0); if (pg == NULL) { return ENOMEM; } /* copy old -> new */ uvm_pagecopy(anon->an_page, pg); /* force reload */ pmap_page_protect(anon->an_page, VM_PROT_NONE); mutex_enter(&uvm_pageqlock); /* KILL loan */ anon->an_page->uanon = NULL; /* in case we owned */ anon->an_page->pqflags &= ~PQ_ANON; if (uobj) { /* if we were receiver of loan */ anon->an_page->loan_count--; } else { /* * we were the lender (A->K); need to remove the page from * pageq's. */ uvm_pagedequeue(anon->an_page); } if (uobj) { mutex_exit(uobj->vmobjlock); } /* install new page in anon */ anon->an_page = pg; pg->uanon = anon; pg->pqflags |= PQ_ANON; uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); pg->flags &= ~(PG_BUSY|PG_FAKE); UVM_PAGE_OWN(pg, NULL); /* done! */ return 0; }
static int uvm_loanzero(struct uvm_faultinfo *ufi, void ***output, int flags) { struct vm_anon *anon; struct vm_page *pg; struct vm_amap *amap = ufi->entry->aref.ar_amap; UVMHIST_FUNC(__func__); UVMHIST_CALLED(loanhist); again: mutex_enter(&uvm_loanzero_object.vmobjlock); /* * first, get ahold of our single zero page. */ if (__predict_false((pg = TAILQ_FIRST(&uvm_loanzero_object.memq)) == NULL)) { while ((pg = uvm_pagealloc(&uvm_loanzero_object, 0, NULL, UVM_PGA_ZERO)) == NULL) { mutex_exit(&uvm_loanzero_object.vmobjlock); uvmfault_unlockall(ufi, amap, NULL, NULL); uvm_wait("loanzero"); if (!uvmfault_relock(ufi)) { return (0); } if (amap) { amap_lock(amap); } goto again; } /* got a zero'd page. */ pg->flags &= ~(PG_WANTED|PG_BUSY|PG_FAKE); pg->flags |= PG_RDONLY; mutex_enter(&uvm_pageqlock); uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); UVM_PAGE_OWN(pg, NULL); } if ((flags & UVM_LOAN_TOANON) == 0) { /* loaning to kernel-page */ mutex_enter(&uvm_pageqlock); pg->loan_count++; mutex_exit(&uvm_pageqlock); mutex_exit(&uvm_loanzero_object.vmobjlock); **output = pg; (*output)++; return (1); } /* * loaning to an anon. check to see if there is already an anon * associated with this page. if so, then just return a reference * to this object. */ if (pg->uanon) { anon = pg->uanon; mutex_enter(&anon->an_lock); anon->an_ref++; mutex_exit(&anon->an_lock); mutex_exit(&uvm_loanzero_object.vmobjlock); **output = anon; (*output)++; return (1); } /* * need to allocate a new anon */ anon = uvm_analloc(); if (anon == NULL) { /* out of swap causes us to fail */ mutex_exit(&uvm_loanzero_object.vmobjlock); uvmfault_unlockall(ufi, amap, NULL, NULL); return (-1); } anon->an_page = pg; pg->uanon = anon; mutex_enter(&uvm_pageqlock); pg->loan_count++; uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); mutex_exit(&anon->an_lock); mutex_exit(&uvm_loanzero_object.vmobjlock); **output = anon; (*output)++; return (1); }
static int uvm_loanuobj(struct uvm_faultinfo *ufi, void ***output, int flags, vaddr_t va) { struct vm_amap *amap = ufi->entry->aref.ar_amap; struct uvm_object *uobj = ufi->entry->object.uvm_obj; struct vm_page *pg; struct vm_anon *anon; int error, npages; bool locked; UVMHIST_FUNC(__func__); UVMHIST_CALLED(loanhist); /* * first we must make sure the page is resident. * * XXXCDC: duplicate code with uvm_fault(). */ mutex_enter(&uobj->vmobjlock); if (uobj->pgops->pgo_get) { /* try locked pgo_get */ npages = 1; pg = NULL; error = (*uobj->pgops->pgo_get)(uobj, va - ufi->entry->start + ufi->entry->offset, &pg, &npages, 0, VM_PROT_READ, MADV_NORMAL, PGO_LOCKED); } else { error = EIO; /* must have pgo_get op */ } /* * check the result of the locked pgo_get. if there is a problem, * then we fail the loan. */ if (error && error != EBUSY) { uvmfault_unlockall(ufi, amap, uobj, NULL); return (-1); } /* * if we need to unlock for I/O, do so now. */ if (error == EBUSY) { uvmfault_unlockall(ufi, amap, NULL, NULL); /* locked: uobj */ npages = 1; error = (*uobj->pgops->pgo_get)(uobj, va - ufi->entry->start + ufi->entry->offset, &pg, &npages, 0, VM_PROT_READ, MADV_NORMAL, PGO_SYNCIO); /* locked: <nothing> */ if (error) { if (error == EAGAIN) { tsleep(&lbolt, PVM, "fltagain2", 0); return (0); } return (-1); } /* * pgo_get was a success. attempt to relock everything. */ locked = uvmfault_relock(ufi); if (locked && amap) amap_lock(amap); uobj = pg->uobject; mutex_enter(&uobj->vmobjlock); /* * verify that the page has not be released and re-verify * that amap slot is still free. if there is a problem we * drop our lock (thus force a lookup refresh/retry). */ if ((pg->flags & PG_RELEASED) != 0 || (locked && amap && amap_lookup(&ufi->entry->aref, ufi->orig_rvaddr - ufi->entry->start))) { if (locked) uvmfault_unlockall(ufi, amap, NULL, NULL); locked = false; } /* * didn't get the lock? release the page and retry. */ if (locked == false) { if (pg->flags & PG_WANTED) { wakeup(pg); } if (pg->flags & PG_RELEASED) { mutex_enter(&uvm_pageqlock); uvm_pagefree(pg); mutex_exit(&uvm_pageqlock); mutex_exit(&uobj->vmobjlock); return (0); } mutex_enter(&uvm_pageqlock); uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); pg->flags &= ~(PG_BUSY|PG_WANTED); UVM_PAGE_OWN(pg, NULL); mutex_exit(&uobj->vmobjlock); return (0); } } KASSERT(uobj == pg->uobject); /* * at this point we have the page we want ("pg") marked PG_BUSY for us * and we have all data structures locked. do the loanout. page can * not be PG_RELEASED (we caught this above). */ if ((flags & UVM_LOAN_TOANON) == 0) { if (uvm_loanpage(&pg, 1)) { uvmfault_unlockall(ufi, amap, uobj, NULL); return (-1); } mutex_exit(&uobj->vmobjlock); **output = pg; (*output)++; return (1); } /* * must be a loan to an anon. check to see if there is already * an anon associated with this page. if so, then just return * a reference to this object. the page should already be * mapped read-only because it is already on loan. */ if (pg->uanon) { anon = pg->uanon; mutex_enter(&anon->an_lock); anon->an_ref++; mutex_exit(&anon->an_lock); if (pg->flags & PG_WANTED) { wakeup(pg); } pg->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(pg, NULL); mutex_exit(&uobj->vmobjlock); **output = anon; (*output)++; return (1); } /* * need to allocate a new anon */ anon = uvm_analloc(); if (anon == NULL) { goto fail; } anon->an_page = pg; pg->uanon = anon; mutex_enter(&uvm_pageqlock); if (pg->wire_count > 0) { mutex_exit(&uvm_pageqlock); UVMHIST_LOG(loanhist, "wired %p", pg,0,0,0); pg->uanon = NULL; anon->an_page = NULL; anon->an_ref--; mutex_exit(&anon->an_lock); uvm_anfree(anon); goto fail; } if (pg->loan_count == 0) { pmap_page_protect(pg, VM_PROT_READ); } pg->loan_count++; uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); if (pg->flags & PG_WANTED) { wakeup(pg); } pg->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(pg, NULL); mutex_exit(&uobj->vmobjlock); mutex_exit(&anon->an_lock); **output = anon; (*output)++; return (1); fail: UVMHIST_LOG(loanhist, "fail", 0,0,0,0); /* * unlock everything and bail out. */ if (pg->flags & PG_WANTED) { wakeup(pg); } pg->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(pg, NULL); uvmfault_unlockall(ufi, amap, uobj, NULL); return (-1); }
/* * uvm_loanbreak: break loan on a uobj page * * => called with uobj locked * => the page should be busy * => return value: * newly allocated page if succeeded */ struct vm_page * uvm_loanbreak(struct vm_page *uobjpage) { struct vm_page *pg; #ifdef DIAGNOSTIC struct uvm_object *uobj = uobjpage->uobject; #endif KASSERT(uobj != NULL); KASSERT(mutex_owned(&uobj->vmobjlock)); KASSERT(uobjpage->flags & PG_BUSY); /* alloc new un-owned page */ pg = uvm_pagealloc(NULL, 0, NULL, 0); if (pg == NULL) return NULL; /* * copy the data from the old page to the new * one and clear the fake flags on the new page (keep it busy). * force a reload of the old page by clearing it from all * pmaps. * transfer dirtiness of the old page to the new page. * then lock the page queues to rename the pages. */ uvm_pagecopy(uobjpage, pg); /* old -> new */ pg->flags &= ~PG_FAKE; pmap_page_protect(uobjpage, VM_PROT_NONE); if ((uobjpage->flags & PG_CLEAN) != 0 && !pmap_clear_modify(uobjpage)) { pmap_clear_modify(pg); pg->flags |= PG_CLEAN; } else { /* uvm_pagecopy marked it dirty */ KASSERT((pg->flags & PG_CLEAN) == 0); /* a object with a dirty page should be dirty. */ KASSERT(!UVM_OBJ_IS_CLEAN(uobj)); } if (uobjpage->flags & PG_WANTED) wakeup(uobjpage); /* uobj still locked */ uobjpage->flags &= ~(PG_WANTED|PG_BUSY); UVM_PAGE_OWN(uobjpage, NULL); mutex_enter(&uvm_pageqlock); /* * replace uobjpage with new page. */ uvm_pagereplace(uobjpage, pg); /* * if the page is no longer referenced by * an anon (i.e. we are breaking an O->K * loan), then remove it from any pageq's. */ if (uobjpage->uanon == NULL) uvm_pagedequeue(uobjpage); /* * at this point we have absolutely no * control over uobjpage */ /* install new page */ uvm_pageactivate(pg); mutex_exit(&uvm_pageqlock); /* * done! loan is broken and "pg" is * PG_BUSY. it can now replace uobjpage. */ return pg; }
int uvmfault_anonget(struct uvm_faultinfo *ufi, struct vm_amap *amap, struct vm_anon *anon) { boolean_t we_own; /* we own anon's page? */ boolean_t locked; /* did we relock? */ struct vm_page *pg; int result; result = 0; /* XXX shut up gcc */ uvmexp.fltanget++; /* bump rusage counters */ if (anon->an_page) curproc->p_ru.ru_minflt++; else curproc->p_ru.ru_majflt++; /* * loop until we get it, or fail. */ while (1) { we_own = FALSE; /* TRUE if we set PG_BUSY on a page */ pg = anon->an_page; /* * if there is a resident page and it is loaned, then anon * may not own it. call out to uvm_anon_lockpage() to ensure * the real owner of the page has been identified and locked. */ if (pg && pg->loan_count) pg = uvm_anon_lockloanpg(anon); /* * page there? make sure it is not busy/released. */ if (pg) { /* * at this point, if the page has a uobject [meaning * we have it on loan], then that uobject is locked * by us! if the page is busy, we drop all the * locks (including uobject) and try again. */ if ((pg->pg_flags & (PG_BUSY|PG_RELEASED)) == 0) { return (VM_PAGER_OK); } atomic_setbits_int(&pg->pg_flags, PG_WANTED); uvmexp.fltpgwait++; /* * the last unlock must be an atomic unlock+wait on * the owner of page */ if (pg->uobject) { /* owner is uobject ? */ uvmfault_unlockall(ufi, amap, NULL, anon); UVM_UNLOCK_AND_WAIT(pg, &pg->uobject->vmobjlock, FALSE, "anonget1",0); } else { /* anon owns page */ uvmfault_unlockall(ufi, amap, NULL, NULL); UVM_UNLOCK_AND_WAIT(pg,&anon->an_lock,0, "anonget2",0); } /* ready to relock and try again */ } else { /* * no page, we must try and bring it in. */ pg = uvm_pagealloc(NULL, 0, anon, 0); if (pg == NULL) { /* out of RAM. */ uvmfault_unlockall(ufi, amap, NULL, anon); uvmexp.fltnoram++; uvm_wait("flt_noram1"); /* ready to relock and try again */ } else { /* we set the PG_BUSY bit */ we_own = TRUE; uvmfault_unlockall(ufi, amap, NULL, anon); /* * we are passing a PG_BUSY+PG_FAKE+PG_CLEAN * page into the uvm_swap_get function with * all data structures unlocked. note that * it is ok to read an_swslot here because * we hold PG_BUSY on the page. */ uvmexp.pageins++; result = uvm_swap_get(pg, anon->an_swslot, PGO_SYNCIO); /* * we clean up after the i/o below in the * "we_own" case */ /* ready to relock and try again */ } } /* * now relock and try again */ locked = uvmfault_relock(ufi); if (locked || we_own) simple_lock(&anon->an_lock); /* * if we own the page (i.e. we set PG_BUSY), then we need * to clean up after the I/O. there are three cases to * consider: * [1] page released during I/O: free anon and ReFault. * [2] I/O not OK. free the page and cause the fault * to fail. * [3] I/O OK! activate the page and sync with the * non-we_own case (i.e. drop anon lock if not locked). */ if (we_own) { if (pg->pg_flags & PG_WANTED) { /* still holding object lock */ wakeup(pg); } /* un-busy! */ atomic_clearbits_int(&pg->pg_flags, PG_WANTED|PG_BUSY|PG_FAKE); UVM_PAGE_OWN(pg, NULL); /* * if we were RELEASED during I/O, then our anon is * no longer part of an amap. we need to free the * anon and try again. */ if (pg->pg_flags & PG_RELEASED) { pmap_page_protect(pg, VM_PROT_NONE); simple_unlock(&anon->an_lock); uvm_anfree(anon); /* frees page for us */ if (locked) uvmfault_unlockall(ufi, amap, NULL, NULL); uvmexp.fltpgrele++; return (VM_PAGER_REFAULT); /* refault! */ } if (result != VM_PAGER_OK) { KASSERT(result != VM_PAGER_PEND); /* remove page from anon */ anon->an_page = NULL; /* * remove the swap slot from the anon * and mark the anon as having no real slot. * don't free the swap slot, thus preventing * it from being used again. */ uvm_swap_markbad(anon->an_swslot, 1); anon->an_swslot = SWSLOT_BAD; /* * note: page was never !PG_BUSY, so it * can't be mapped and thus no need to * pmap_page_protect it... */ uvm_lock_pageq(); uvm_pagefree(pg); uvm_unlock_pageq(); if (locked) uvmfault_unlockall(ufi, amap, NULL, anon); else simple_unlock(&anon->an_lock); return (VM_PAGER_ERROR); } /* * must be OK, clear modify (already PG_CLEAN) * and activate */ pmap_clear_modify(pg); uvm_lock_pageq(); uvm_pageactivate(pg); uvm_unlock_pageq(); if (!locked) simple_unlock(&anon->an_lock); } /* * we were not able to relock. restart fault. */ if (!locked) return (VM_PAGER_REFAULT); /* * verify no one has touched the amap and moved the anon on us. */ if (ufi != NULL && amap_lookup(&ufi->entry->aref, ufi->orig_rvaddr - ufi->entry->start) != anon) { uvmfault_unlockall(ufi, amap, NULL, anon); return (VM_PAGER_REFAULT); } /* * try it again! */ uvmexp.fltanretry++; continue; } /* while (1) */ /*NOTREACHED*/ }
vaddr_t uvm_km_alloc1(struct vm_map *map, vsize_t size, vsize_t align, boolean_t zeroit) { vaddr_t kva, loopva; voff_t offset; struct vm_page *pg; UVMHIST_FUNC("uvm_km_alloc1"); UVMHIST_CALLED(maphist); UVMHIST_LOG(maphist,"(map=%p, size=0x%lx)", map, size,0,0); KASSERT(vm_map_pmap(map) == pmap_kernel()); size = round_page(size); kva = vm_map_min(map); /* hint */ /* * allocate some virtual space */ if (__predict_false(uvm_map(map, &kva, size, uvm.kernel_object, UVM_UNKNOWN_OFFSET, align, UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE, UVM_ADV_RANDOM, 0)) != 0)) { UVMHIST_LOG(maphist,"<- done (no VM)",0,0,0,0); return(0); } /* * recover object offset from virtual address */ offset = kva - vm_map_min(kernel_map); UVMHIST_LOG(maphist," kva=0x%lx, offset=0x%lx", kva, offset,0,0); /* * now allocate the memory. we must be careful about released pages. */ loopva = kva; while (size) { simple_lock(&uvm.kernel_object->vmobjlock); pg = uvm_pagelookup(uvm.kernel_object, offset); /* * if we found a page in an unallocated region, it must be * released */ if (pg) { if ((pg->pg_flags & PG_RELEASED) == 0) panic("uvm_km_alloc1: non-released page"); atomic_setbits_int(&pg->pg_flags, PG_WANTED); UVM_UNLOCK_AND_WAIT(pg, &uvm.kernel_object->vmobjlock, FALSE, "km_alloc", 0); continue; /* retry */ } /* allocate ram */ pg = uvm_pagealloc(uvm.kernel_object, offset, NULL, 0); if (pg) { atomic_clearbits_int(&pg->pg_flags, PG_BUSY); UVM_PAGE_OWN(pg, NULL); } simple_unlock(&uvm.kernel_object->vmobjlock); if (__predict_false(pg == NULL)) { if (curproc == uvm.pagedaemon_proc) { /* * It is unfeasible for the page daemon to * sleep for memory, so free what we have * allocated and fail. */ uvm_unmap(map, kva, loopva - kva); return (NULL); } else { uvm_wait("km_alloc1w"); /* wait for memory */ continue; } } /* * map it in; note we're never called with an intrsafe * object, so we always use regular old pmap_enter(). */ pmap_enter(map->pmap, loopva, VM_PAGE_TO_PHYS(pg), UVM_PROT_ALL, PMAP_WIRED | VM_PROT_READ | VM_PROT_WRITE); loopva += PAGE_SIZE; offset += PAGE_SIZE; size -= PAGE_SIZE; } pmap_update(map->pmap); /* * zero on request (note that "size" is now zero due to the above loop * so we need to subtract kva from loopva to reconstruct the size). */ if (zeroit) memset((caddr_t)kva, 0, loopva - kva); UVMHIST_LOG(maphist,"<- done (kva=0x%lx)", kva,0,0,0); return(kva); }
vaddr_t uvm_km_kmemalloc(struct vm_map *map, struct uvm_object *obj, vsize_t size, int flags) { vaddr_t kva, loopva; voff_t offset; struct vm_page *pg; int mapflags; UVMHIST_FUNC("uvm_km_kmemalloc"); UVMHIST_CALLED(maphist); UVMHIST_LOG(maphist," (map=%p, obj=%p, size=0x%lx, flags=%d)", map, obj, size, flags); KASSERT(vm_map_pmap(map) == pmap_kernel()); /* * we cannot yet make pmap_enter() not sleep * and thus demand that we are called with NOWAIT in that case */ KASSERT(!((flags & UVM_KMF_NOWAIT) && obj)); /* * setup for call */ mapflags = flags & UVM_KMF_NOWAIT? UVM_FLAG_NOWAIT : 0; mapflags |= flags & UVM_KMF_TRYLOCK; size = round_page(size); kva = vm_map_min(map); /* hint */ /* * allocate some virtual space */ if (__predict_false(uvm_map(map, &kva, size, obj, UVM_UNKNOWN_OFFSET, 0, UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, UVM_INH_NONE, UVM_ADV_RANDOM, mapflags)) != 0)) { UVMHIST_LOG(maphist, "<- done (no VM)",0,0,0,0); return(0); } /* * if all we wanted was VA, return now */ if (flags & UVM_KMF_VALLOC) { UVMHIST_LOG(maphist,"<- done valloc (kva=0x%lx)", kva,0,0,0); return(kva); } /* * recover object offset from virtual address */ if (obj != NULL) offset = kva - vm_map_min(kernel_map); else offset = 0; UVMHIST_LOG(maphist, " kva=0x%lx, offset=0x%lx", kva, offset,0,0); /* * now allocate and map in the memory... note that we are the only ones * whom should ever get a handle on this area of VM. */ loopva = kva; while (loopva != kva + size) { pg = uvm_pagealloc(obj, offset, NULL, 0); if (pg) { atomic_clearbits_int(&pg->pg_flags, PG_BUSY); UVM_PAGE_OWN(pg, NULL); } if (__predict_false(pg == NULL)) { if ((flags & UVM_KMF_NOWAIT) || ((flags & UVM_KMF_CANFAIL) && uvmexp.swpgonly == uvmexp.swpages)) { /* free everything! */ uvm_unmap(map, kva, kva + size); return (0); } else { uvm_wait("km_getwait2"); /* sleep here */ continue; } } /* * map it in: note that we call pmap_enter with the map and * object unlocked in case we are kmem_map. * * pager mappings that must not sleep here will incidently * be installed using pmap_kenter_pa() and thus not sleep! */ if (obj == NULL) { pmap_kenter_pa(loopva, VM_PAGE_TO_PHYS(pg), UVM_PROT_RW); } else { pmap_enter(map->pmap, loopva, VM_PAGE_TO_PHYS(pg), UVM_PROT_RW, PMAP_WIRED | VM_PROT_READ | VM_PROT_WRITE); } loopva += PAGE_SIZE; offset += PAGE_SIZE; } pmap_update(pmap_kernel()); UVMHIST_LOG(maphist,"<- done (kva=0x%lx)", kva,0,0,0); return(kva); }