Date: Thu, 28 Aug 2014 11:30:53 -0500 From: Alan Cox <alc@rice.edu> To: Adrian Chadd <adrian@freebsd.org> Cc: Alan Cox <alc@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r269134 - head/sys/vm Message-ID: <72B80282-6FA1-4481-8333-37EF3A58FB74@rice.edu> In-Reply-To: <CAJ-VmokUPtJQd1_Vp5c%2B0fGvWE_iDHszNGbTnta6VGwFr8oiOQ@mail.gmail.com> References: <201407261810.s6QIAIIj049439@svn.freebsd.org> <CAJ-VmokUPtJQd1_Vp5c%2B0fGvWE_iDHszNGbTnta6VGwFr8oiOQ@mail.gmail.com>
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On Aug 28, 2014, at 3:30 AM, Adrian Chadd wrote: > Hi Alan! >=20 > I just reverted back to the commit before this one and it fixed my = MIPS32 boot. >=20 > Would you have some time to help me help you figure out why things = broke? :) >=20 Have you tried booting a kernel based on r269134? At the time, I tested = a 64-bit MIPS kernel on gxemul, and it ran ok. Also, Hiren reports that = a 32-bit kernel from about two weeks after r269134 works for him. >=20 >=20 >=20 >=20 > -a >=20 >=20 > On 26 July 2014 11:10, Alan Cox <alc@freebsd.org> wrote: >> Author: alc >> Date: Sat Jul 26 18:10:18 2014 >> New Revision: 269134 >> URL: http://svnweb.freebsd.org/changeset/base/269134 >>=20 >> Log: >> When unwiring a region of an address space, do not assume that the >> underlying physical pages are mapped by the pmap. If, for example, = the >> application has performed an mprotect(..., PROT_NONE) on any part of = the >> wired region, then those pages will no longer be mapped by the pmap. >> So, using the pmap to lookup the wired pages in order to unwire them >> doesn't always work, and when it doesn't work wired pages are = leaked. >>=20 >> To avoid the leak, introduce and use a new function = vm_object_unwire() >> that locates the wired pages by traversing the object and its = backing >> objects. >>=20 >> At the same time, switch from using pmap_change_wiring() to the = recently >> introduced function pmap_unwire() for unwiring the region's = mappings. >> pmap_unwire() is faster, because it operates a range of virtual = addresses >> rather than a single virtual page at a time. Moreover, by operating = on >> a range, it is superpage friendly. It doesn't waste time performing >> unnecessary demotions. >>=20 >> Reported by: markj >> Reviewed by: kib >> Tested by: pho, jmg (arm) >> Sponsored by: EMC / Isilon Storage Division >>=20 >> Modified: >> head/sys/vm/vm_extern.h >> head/sys/vm/vm_fault.c >> head/sys/vm/vm_map.c >> head/sys/vm/vm_object.c >> head/sys/vm/vm_object.h >>=20 >> Modified: head/sys/vm/vm_extern.h >> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D >> --- head/sys/vm/vm_extern.h Sat Jul 26 17:59:25 2014 = (r269133) >> +++ head/sys/vm/vm_extern.h Sat Jul 26 18:10:18 2014 = (r269134) >> @@ -81,7 +81,6 @@ int vm_fault_hold(vm_map_t map, vm_offse >> int fault_flags, vm_page_t *m_hold); >> int vm_fault_quick_hold_pages(vm_map_t map, vm_offset_t addr, = vm_size_t len, >> vm_prot_t prot, vm_page_t *ma, int max_count); >> -void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t); >> int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t); >> int vm_forkproc(struct thread *, struct proc *, struct thread *, = struct vmspace *, int); >> void vm_waitproc(struct proc *); >>=20 >> Modified: head/sys/vm/vm_fault.c >> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D >> --- head/sys/vm/vm_fault.c Sat Jul 26 17:59:25 2014 = (r269133) >> +++ head/sys/vm/vm_fault.c Sat Jul 26 18:10:18 2014 = (r269134) >> @@ -106,6 +106,7 @@ __FBSDID("$FreeBSD$"); >> #define PFFOR 4 >>=20 >> static int vm_fault_additional_pages(vm_page_t, int, int, vm_page_t = *, int *); >> +static void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t, = boolean_t); >>=20 >> #define VM_FAULT_READ_BEHIND 8 >> #define VM_FAULT_READ_MAX (1 + VM_FAULT_READ_AHEAD_MAX) >> @@ -1186,7 +1187,7 @@ vm_fault_wire(vm_map_t map, vm_offset_t >> * >> * Unwire a range of virtual addresses in a map. >> */ >> -void >> +static void >> vm_fault_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end, >> boolean_t fictitious) >> { >>=20 >> Modified: head/sys/vm/vm_map.c >> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D >> --- head/sys/vm/vm_map.c Sat Jul 26 17:59:25 2014 = (r269133) >> +++ head/sys/vm/vm_map.c Sat Jul 26 18:10:18 2014 = (r269134) >> @@ -132,6 +132,7 @@ static void _vm_map_init(vm_map_t map, p >> vm_offset_t max); >> static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t = system_map); >> static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry); >> +static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry); >> #ifdef INVARIANTS >> static void vm_map_zdtor(void *mem, int size, void *arg); >> static void vmspace_zdtor(void *mem, int size, void *arg); >> @@ -2393,16 +2394,10 @@ done: >> (entry->eflags & MAP_ENTRY_USER_WIRED))) { >> if (user_unwire) >> entry->eflags &=3D = ~MAP_ENTRY_USER_WIRED; >> - entry->wired_count--; >> - if (entry->wired_count =3D=3D 0) { >> - /* >> - * Retain the map lock. >> - */ >> - vm_fault_unwire(map, entry->start, = entry->end, >> - entry->object.vm_object !=3D NULL = && >> - (entry->object.vm_object->flags & >> - OBJ_FICTITIOUS) !=3D 0); >> - } >> + if (entry->wired_count =3D=3D 1) >> + vm_map_entry_unwire(map, entry); >> + else >> + entry->wired_count--; >> } >> KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) !=3D = 0, >> ("vm_map_unwire: in-transition flag missing %p", = entry)); >> @@ -2635,19 +2630,12 @@ done: >> * unnecessary. >> */ >> entry->wired_count =3D 0; >> - } else { >> - if (!user_wire || >> - (entry->eflags & MAP_ENTRY_USER_WIRED) =3D=3D= 0) >> + } else if (!user_wire || >> + (entry->eflags & MAP_ENTRY_USER_WIRED) =3D=3D 0) = { >> + if (entry->wired_count =3D=3D 1) >> + vm_map_entry_unwire(map, entry); >> + else >> entry->wired_count--; >> - if (entry->wired_count =3D=3D 0) { >> - /* >> - * Retain the map lock. >> - */ >> - vm_fault_unwire(map, entry->start, = entry->end, >> - entry->object.vm_object !=3D NULL = && >> - (entry->object.vm_object->flags & >> - OBJ_FICTITIOUS) !=3D 0); >> - } >> } >> next_entry_done: >> KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) !=3D = 0, >> @@ -2783,9 +2771,13 @@ vm_map_sync( >> static void >> vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) >> { >> - vm_fault_unwire(map, entry->start, entry->end, >> - entry->object.vm_object !=3D NULL && >> - (entry->object.vm_object->flags & OBJ_FICTITIOUS) !=3D = 0); >> + >> + VM_MAP_ASSERT_LOCKED(map); >> + KASSERT(entry->wired_count > 0, >> + ("vm_map_entry_unwire: entry %p isn't wired", entry)); >> + pmap_unwire(map->pmap, entry->start, entry->end); >> + vm_object_unwire(entry->object.vm_object, entry->offset, = entry->end - >> + entry->start, PQ_ACTIVE); >> entry->wired_count =3D 0; >> } >>=20 >>=20 >> Modified: head/sys/vm/vm_object.c >> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D >> --- head/sys/vm/vm_object.c Sat Jul 26 17:59:25 2014 = (r269133) >> +++ head/sys/vm/vm_object.c Sat Jul 26 18:10:18 2014 = (r269134) >> @@ -2202,6 +2202,78 @@ vm_object_set_writeable_dirty(vm_object_ >> vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); >> } >>=20 >> +/* >> + * vm_object_unwire: >> + * >> + * For each page offset within the specified range of the given = object, >> + * find the highest-level page in the shadow chain and unwire = it. A page >> + * must exist at every page offset, and the highest-level page = must be >> + * wired. >> + */ >> +void >> +vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t = length, >> + uint8_t queue) >> +{ >> + vm_object_t tobject; >> + vm_page_t m, tm; >> + vm_pindex_t end_pindex, pindex, tpindex; >> + int depth, locked_depth; >> + >> + KASSERT((offset & PAGE_MASK) =3D=3D 0, >> + ("vm_object_unwire: offset is not page aligned")); >> + KASSERT((length & PAGE_MASK) =3D=3D 0, >> + ("vm_object_unwire: length is not a multiple of = PAGE_SIZE")); >> + /* The wired count of a fictitious page never changes. */ >> + if ((object->flags & OBJ_FICTITIOUS) !=3D 0) >> + return; >> + pindex =3D OFF_TO_IDX(offset); >> + end_pindex =3D pindex + atop(length); >> + locked_depth =3D 1; >> + VM_OBJECT_RLOCK(object); >> + m =3D vm_page_find_least(object, pindex); >> + while (pindex < end_pindex) { >> + if (m =3D=3D NULL || pindex < m->pindex) { >> + /* >> + * The first object in the shadow chain = doesn't >> + * contain a page at the current index. = Therefore, >> + * the page must exist in a backing object. >> + */ >> + tobject =3D object; >> + tpindex =3D pindex; >> + depth =3D 0; >> + do { >> + tpindex +=3D >> + = OFF_TO_IDX(tobject->backing_object_offset); >> + tobject =3D tobject->backing_object; >> + KASSERT(tobject !=3D NULL, >> + ("vm_object_unwire: missing = page")); >> + if ((tobject->flags & OBJ_FICTITIOUS) = !=3D 0) >> + goto next_page; >> + depth++; >> + if (depth =3D=3D locked_depth) { >> + locked_depth++; >> + VM_OBJECT_RLOCK(tobject); >> + } >> + } while ((tm =3D vm_page_lookup(tobject, = tpindex)) =3D=3D >> + NULL); >> + } else { >> + tm =3D m; >> + m =3D TAILQ_NEXT(m, listq); >> + } >> + vm_page_lock(tm); >> + vm_page_unwire(tm, queue); >> + vm_page_unlock(tm); >> +next_page: >> + pindex++; >> + } >> + /* Release the accumulated object locks. */ >> + for (depth =3D 0; depth < locked_depth; depth++) { >> + tobject =3D object->backing_object; >> + VM_OBJECT_RUNLOCK(object); >> + object =3D tobject; >> + } >> +} >> + >> #include "opt_ddb.h" >> #ifdef DDB >> #include <sys/kernel.h> >>=20 >> Modified: head/sys/vm/vm_object.h >> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D >> --- head/sys/vm/vm_object.h Sat Jul 26 17:59:25 2014 = (r269133) >> +++ head/sys/vm/vm_object.h Sat Jul 26 18:10:18 2014 = (r269134) >> @@ -291,6 +291,8 @@ void vm_object_shadow (vm_object_t *, vm >> void vm_object_split(vm_map_entry_t); >> boolean_t vm_object_sync(vm_object_t, vm_ooffset_t, vm_size_t, = boolean_t, >> boolean_t); >> +void vm_object_unwire(vm_object_t object, vm_ooffset_t offset, >> + vm_size_t length, uint8_t queue); >> #endif /* _KERNEL */ >>=20 >> #endif /* _VM_OBJECT_ */ >>=20 >=20
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