Clean up, sprinkle asserts, consify, use unsigned, use kmem_zalloc instead
of memset, reduce the scope of some variables, improve some comments. No functional change intended.
This commit is contained in:
rmind
parent
1885100a7e
commit
10583b12ce
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@ -1,4 +1,4 @@
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/* $NetBSD: uvm_amap.c,v 1.94 2011/06/18 20:51:22 rmind Exp $ */
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/* $NetBSD: uvm_amap.c,v 1.95 2011/06/18 21:13:29 rmind Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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@ -35,7 +35,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: uvm_amap.c,v 1.94 2011/06/18 20:51:22 rmind Exp $");
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__KERNEL_RCSID(0, "$NetBSD: uvm_amap.c,v 1.95 2011/06/18 21:13:29 rmind Exp $");
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#include "opt_uvmhist.h"
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@ -160,24 +160,22 @@ pp_setreflen(int *ppref, int offset, int ref, int len)
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#endif /* UVM_AMAP_PPREF */
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/*
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* amap_alloc1: internal function that allocates an amap, but does not
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* init the overlay.
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* amap_alloc1: allocate an amap, but do not initialise the overlay.
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*
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* => lock is not initialized
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* => Note: lock is not set.
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*/
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static inline struct vm_amap *
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amap_alloc1(int slots, int padslots, int waitf)
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amap_alloc1(int slots, int padslots, int flags)
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{
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const bool nowait = (flags & UVM_FLAG_NOWAIT) != 0;
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const km_flag_t kmflags = nowait ? KM_NOSLEEP : KM_SLEEP;
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struct vm_amap *amap;
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int totalslots;
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km_flag_t kmflags;
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amap = pool_cache_get(&uvm_amap_cache,
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((waitf & UVM_FLAG_NOWAIT) != 0) ? PR_NOWAIT : PR_WAITOK);
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if (amap == NULL)
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return(NULL);
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kmflags = ((waitf & UVM_FLAG_NOWAIT) != 0) ? KM_NOSLEEP : KM_SLEEP;
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amap = pool_cache_get(&uvm_amap_cache, nowait ? PR_NOWAIT : PR_WAITOK);
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if (amap == NULL) {
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return NULL;
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}
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totalslots = amap_roundup_slots(slots + padslots);
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amap->am_lock = NULL;
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amap->am_ref = 1;
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@ -206,7 +204,7 @@ amap_alloc1(int slots, int padslots, int waitf)
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if (amap->am_anon == NULL)
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goto fail3;
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return(amap);
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return amap;
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fail3:
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kmem_free(amap->am_bckptr, totalslots * sizeof(int));
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@ -219,13 +217,13 @@ fail1:
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* XXX hack to tell the pagedaemon how many pages we need,
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* since we can need more than it would normally free.
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*/
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if ((waitf & UVM_FLAG_NOWAIT) != 0) {
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if (nowait) {
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extern u_int uvm_extrapages;
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atomic_add_int(&uvm_extrapages,
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((sizeof(int) * 2 + sizeof(struct vm_anon *)) *
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totalslots) >> PAGE_SHIFT);
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}
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return (NULL);
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return NULL;
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}
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/*
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@ -647,7 +645,8 @@ void
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amap_share_protect(struct vm_map_entry *entry, vm_prot_t prot)
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{
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struct vm_amap *amap = entry->aref.ar_amap;
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int slots, lcv, slot, stop;
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u_int slots, lcv, slot, stop;
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struct vm_anon *anon;
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KASSERT(mutex_owned(amap->am_lock));
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@ -655,48 +654,57 @@ amap_share_protect(struct vm_map_entry *entry, vm_prot_t prot)
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stop = entry->aref.ar_pageoff + slots;
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if (slots < amap->am_nused) {
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/* cheaper to traverse am_anon */
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/*
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* Cheaper to traverse am_anon.
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*/
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for (lcv = entry->aref.ar_pageoff ; lcv < stop ; lcv++) {
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if (amap->am_anon[lcv] == NULL)
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anon = amap->am_anon[lcv];
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if (anon == NULL) {
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continue;
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if (amap->am_anon[lcv]->an_page != NULL)
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pmap_page_protect(amap->am_anon[lcv]->an_page,
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prot);
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}
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if (anon->an_page) {
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pmap_page_protect(anon->an_page, prot);
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}
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}
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return;
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}
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/* cheaper to traverse am_slots */
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/*
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* Cheaper to traverse am_slots.
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*/
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for (lcv = 0 ; lcv < amap->am_nused ; lcv++) {
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slot = amap->am_slots[lcv];
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if (slot < entry->aref.ar_pageoff || slot >= stop)
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if (slot < entry->aref.ar_pageoff || slot >= stop) {
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continue;
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if (amap->am_anon[slot]->an_page != NULL)
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pmap_page_protect(amap->am_anon[slot]->an_page, prot);
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}
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anon = amap->am_anon[slot];
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if (anon->an_page) {
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pmap_page_protect(anon->an_page, prot);
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}
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}
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}
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/*
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* amap_wipeout: wipeout all anon's in an amap; then free the amap!
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*
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* => called from amap_unref when the final reference to an amap is
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* discarded (i.e. when reference count drops to 0)
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* => the amap should be locked (by the caller)
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* => Called from amap_unref(), when reference count drops to zero.
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* => amap must be locked.
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*/
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void
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amap_wipeout(struct vm_amap *amap)
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{
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int lcv, slot;
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struct vm_anon *anon;
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u_int lcv;
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UVMHIST_FUNC("amap_wipeout"); UVMHIST_CALLED(maphist);
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UVMHIST_LOG(maphist,"(amap=0x%x)", amap, 0,0,0);
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KASSERT(mutex_owned(amap->am_lock));
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KASSERT(amap->am_ref == 0);
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if (__predict_false((amap->am_flags & AMAP_SWAPOFF) != 0)) {
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if (__predict_false(amap->am_flags & AMAP_SWAPOFF)) {
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/*
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* amap_swap_off will call us again.
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* Note: amap_swap_off() will call us again.
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*/
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amap_unlock(amap);
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return;
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@ -704,7 +712,8 @@ amap_wipeout(struct vm_amap *amap)
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amap_list_remove(amap);
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for (lcv = 0 ; lcv < amap->am_nused ; lcv++) {
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int refs;
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struct vm_anon *anon;
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u_int slot;
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slot = amap->am_slots[lcv];
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anon = amap->am_anon[slot];
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@ -713,27 +722,26 @@ amap_wipeout(struct vm_amap *amap)
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KASSERT(anon->an_lock == amap->am_lock);
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UVMHIST_LOG(maphist," processing anon 0x%x, ref=%d", anon,
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anon->an_ref, 0, 0);
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refs = --anon->an_ref;
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if (refs == 0) {
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/*
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* we had the last reference to a vm_anon. free it.
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*/
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/*
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* Drop the reference, and free the anon, if it is last.
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*/
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if (--anon->an_ref == 0) {
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uvm_anfree(anon);
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}
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if (curlwp->l_cpu->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
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if (curlwp->l_cpu->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) {
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preempt();
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}
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}
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/*
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* now we free the map
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* Finally, destroy the amap.
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*/
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amap->am_nused = 0;
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amap_unlock(amap);
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amap_free(amap); /* will unlock and free amap */
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amap_free(amap);
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UVMHIST_LOG(maphist,"<- done!", 0,0,0,0);
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}
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@ -947,9 +955,9 @@ void
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amap_cow_now(struct vm_map *map, struct vm_map_entry *entry)
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{
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struct vm_amap *amap = entry->aref.ar_amap;
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int lcv, slot;
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struct vm_anon *anon, *nanon;
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struct vm_page *pg, *npg;
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u_int lcv, slot;
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/*
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* note that if we unlock the amap then we must ReStart the "lcv" for
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@ -960,20 +968,15 @@ amap_cow_now(struct vm_map *map, struct vm_map_entry *entry)
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ReStart:
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amap_lock(amap);
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for (lcv = 0 ; lcv < amap->am_nused ; lcv++) {
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/*
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* get the page
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*/
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slot = amap->am_slots[lcv];
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anon = amap->am_anon[slot];
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KASSERT(anon->an_lock == amap->am_lock);
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/*
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* If the anon has only one ref, we must have already copied it.
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* This can happen if we needed to sleep waiting for memory
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* in a previous run through this loop. The new page might
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* even have been paged out, since the new page is not wired.
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* If anon has only one reference - we must have already
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* copied it. This can happen if we needed to sleep waiting
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* for memory in a previous run through this loop. The new
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* page might even have been paged out, since is not wired.
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*/
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if (anon->an_ref == 1) {
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@ -1000,7 +1003,7 @@ ReStart:
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KASSERT(pg->uanon == anon && pg->uobject == NULL);
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/*
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* if the page is busy then we have to unlock, wait for
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* If the page is busy, then we have to unlock, wait for
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* it and then restart.
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*/
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@ -1012,14 +1015,16 @@ ReStart:
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}
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/*
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* ok, time to do a copy-on-write to a new anon
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* Perform a copy-on-write.
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* First - get a new anon and a page.
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*/
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nanon = uvm_analloc();
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if (nanon) {
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npg = uvm_pagealloc(NULL, 0, nanon, 0);
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} else
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npg = NULL; /* XXX: quiet gcc warning */
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} else {
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npg = NULL;
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}
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if (nanon == NULL || npg == NULL) {
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/*
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@ -1037,19 +1042,20 @@ ReStart:
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}
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/*
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* got it... now we can copy the data and replace anon
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* with our new one...
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* Copy the data and replace anon with the new one.
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* Also, setup its lock (share the with amap's lock).
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*/
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nanon->an_lock = amap->am_lock;
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mutex_obj_hold(nanon->an_lock);
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uvm_pagecopy(pg, npg); /* old -> new */
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anon->an_ref--; /* can't drop to zero */
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amap->am_anon[slot] = nanon; /* replace */
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uvm_pagecopy(pg, npg);
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anon->an_ref--;
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KASSERT(anon->an_ref > 0);
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amap->am_anon[slot] = nanon;
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/*
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* drop PG_BUSY on new page ... since we have had its owner
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* locked the whole time it can't be PG_RELEASED or PG_WANTED.
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* Drop PG_BUSY on new page. Since its owner was locked all
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* this time - it cannot be PG_RELEASED or PG_WANTED.
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*/
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mutex_enter(&uvm_pageqlock);
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@ -1071,85 +1077,75 @@ ReStart:
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void
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amap_splitref(struct vm_aref *origref, struct vm_aref *splitref, vaddr_t offset)
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{
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int leftslots;
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struct vm_amap *amap;
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struct vm_amap *amap = origref->ar_amap;
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u_int leftslots;
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KASSERT(splitref->ar_amap == origref->ar_amap);
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AMAP_B2SLOT(leftslots, offset);
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KASSERT(leftslots != 0);
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amap = origref->ar_amap;
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amap_lock(amap);
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/*
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* now: amap is locked and we have a valid am_mapped array.
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*/
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KASSERT(amap->am_nslot - origref->ar_pageoff - leftslots > 0);
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#ifdef UVM_AMAP_PPREF
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/*
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* establish ppref before we add a duplicate reference to the amap
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*/
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if (amap->am_ppref == NULL)
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/* Establish ppref before we add a duplicate reference to the amap. */
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if (amap->am_ppref == NULL) {
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amap_pp_establish(amap, origref->ar_pageoff);
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}
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#endif
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amap->am_ref++; /* not a share reference */
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/* Note: not a share reference. */
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amap->am_ref++;
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splitref->ar_pageoff = origref->ar_pageoff + leftslots;
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amap_unlock(amap);
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}
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#ifdef UVM_AMAP_PPREF
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/*
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* amap_pp_establish: add a ppref array to an amap, if possible
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* amap_pp_establish: add a ppref array to an amap, if possible.
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*
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* => amap locked by caller
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* => amap should be locked by caller.
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*/
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void
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amap_pp_establish(struct vm_amap *amap, vaddr_t offset)
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{
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const size_t sz = amap->am_maxslot * sizeof(*amap->am_ppref);
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amap->am_ppref = kmem_alloc(amap->am_maxslot * sizeof(*amap->am_ppref),
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KM_NOSLEEP);
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/*
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* if we fail then we just won't use ppref for this amap
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*/
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KASSERT(mutex_owned(amap->am_lock));
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amap->am_ppref = kmem_zalloc(sz, KM_NOSLEEP);
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if (amap->am_ppref == NULL) {
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amap->am_ppref = PPREF_NONE; /* not using it */
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/* Failure - just do not use ppref. */
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amap->am_ppref = PPREF_NONE;
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return;
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}
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memset(amap->am_ppref, 0, sizeof(int) * amap->am_maxslot);
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pp_setreflen(amap->am_ppref, 0, 0, offset);
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pp_setreflen(amap->am_ppref, offset, amap->am_ref,
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amap->am_nslot - offset);
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return;
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}
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/*
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* amap_pp_adjref: adjust reference count to a part of an amap using the
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* per-page reference count array.
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*
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* => map and amap locked by caller
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* => caller must check that ppref != PPREF_NONE before calling
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* => caller must check that ppref != PPREF_NONE before calling.
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* => map and amap must be locked.
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*/
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void
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amap_pp_adjref(struct vm_amap *amap, int curslot, vsize_t slotlen, int adjval,
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struct vm_anon **tofree)
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struct vm_anon **tofree)
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{
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int stopslot, *ppref, lcv, prevlcv;
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int ref, len, prevref, prevlen;
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KASSERT(mutex_owned(amap->am_lock));
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stopslot = curslot + slotlen;
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ppref = amap->am_ppref;
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prevlcv = 0;
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/*
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* first advance to the correct place in the ppref array,
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* fragment if needed.
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* Advance to the correct place in the array, fragment if needed.
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*/
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for (lcv = 0 ; lcv < curslot ; lcv += len) {
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@ -1161,20 +1157,20 @@ amap_pp_adjref(struct vm_amap *amap, int curslot, vsize_t slotlen, int adjval,
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}
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prevlcv = lcv;
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}
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if (lcv != 0)
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pp_getreflen(ppref, prevlcv, &prevref, &prevlen);
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else {
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/* Ensure that the "prevref == ref" test below always
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* fails, since we're starting from the beginning of
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* the ppref array; that is, there is no previous
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* chunk.
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if (lcv) {
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/*
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* Ensure that the "prevref == ref" test below always
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* fails, since we are starting from the beginning of
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* the ppref array; that is, there is no previous chunk.
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*/
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prevref = -1;
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prevlen = 0;
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} else {
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pp_getreflen(ppref, prevlcv, &prevref, &prevlen);
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}
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/*
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* now adjust reference counts in range. merge the first
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* Now adjust reference counts in range. Merge the first
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* changed entry with the last unchanged entry if possible.
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*/
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KASSERT(lcv == curslot);
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@ -1193,10 +1189,10 @@ amap_pp_adjref(struct vm_amap *amap, int curslot, vsize_t slotlen, int adjval,
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} else {
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pp_setreflen(ppref, lcv, ref, len);
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}
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if (ref == 0)
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if (ref == 0) {
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amap_wiperange(amap, lcv, len, tofree);
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}
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}
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}
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/*
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|
@ -1207,10 +1203,11 @@ amap_pp_adjref(struct vm_amap *amap, int curslot, vsize_t slotlen, int adjval,
|
|||
*/
|
||||
void
|
||||
amap_wiperange(struct vm_amap *amap, int slotoff, int slots,
|
||||
struct vm_anon **tofree)
|
||||
struct vm_anon **tofree)
|
||||
{
|
||||
int byanon, lcv, stop, curslot, ptr, slotend;
|
||||
u_int lcv, stop, curslot, ptr, slotend;
|
||||
struct vm_anon *anon;
|
||||
bool byanon;
|
||||
|
||||
KASSERT(mutex_owned(amap->am_lock));
|
||||
|
||||
|
|
@ -1232,8 +1229,6 @@ amap_wiperange(struct vm_amap *amap, int slotoff, int slots,
|
|||
}
|
||||
|
||||
while (lcv < stop) {
|
||||
int refs;
|
||||
|
||||
if (byanon) {
|
||||
curslot = lcv++; /* lcv advances here */
|
||||
if (amap->am_anon[curslot] == NULL)
|
||||
|
|
@ -1249,7 +1244,7 @@ amap_wiperange(struct vm_amap *amap, int slotoff, int slots,
|
|||
anon = amap->am_anon[curslot];
|
||||
|
||||
/*
|
||||
* remove it from the amap
|
||||
* Remove anon from the amap.
|
||||
*/
|
||||
|
||||
amap->am_anon[curslot] = NULL;
|
||||
|
|
@ -1263,19 +1258,15 @@ amap_wiperange(struct vm_amap *amap, int slotoff, int slots,
|
|||
amap->am_nused--;
|
||||
|
||||
/*
|
||||
* drop anon reference count
|
||||
* Drop its reference count.
|
||||
*/
|
||||
|
||||
KASSERT(anon->an_lock == amap->am_lock);
|
||||
refs = --anon->an_ref;
|
||||
if (refs == 0) {
|
||||
|
||||
if (--anon->an_ref == 0) {
|
||||
/*
|
||||
* we just eliminated the last reference to an anon.
|
||||
* defer freeing it as uvm_anfree() can unlock the
|
||||
* amap.
|
||||
* Eliminated the last reference to an anon - defer
|
||||
* freeing as uvm_anfree() can unlock the amap.
|
||||
*/
|
||||
|
||||
anon->an_link = *tofree;
|
||||
*tofree = anon;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue