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Enable the use of VM_PHYSSEG_SPARSE on amd64 and i386, making it the default

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on i386 PAE.  Previously, VM_PHYSSEG_SPARSE could not be used on amd64 and
i386 because vm_page_startup() would not create vm_page structures for the
kernel page table pages allocated during pmap_bootstrap() but those vm_page
structures are needed when the kernel attempts to promote the corresponding
kernel virtual addresses to superpage mappings.  To address this problem, a
new public function, vm_phys_add_seg(), is introduced and vm_phys_init() is
updated to reflect the creation of vm_phys_seg structures by calls to
vm_phys_add_seg().

Discussed with:	Svatopluk Kraus
MFC after:	3 weeks
Sponsored by:	EMC / Isilon Storage Division
This commit is contained in:
Alan Cox 2014-11-15 23:40:44 +00:00
parent eb81bf559c
commit 271f0f1219
6 changed files with 108 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
sys/amd64/amd64/pmap.c
View File

@ -833,6 +833,15 @@ pmap_bootstrap(vm_paddr_t *firstaddr)
*/
create_pagetables(firstaddr);
/*
* Add a physical memory segment (vm_phys_seg) corresponding to the
* preallocated kernel page table pages so that vm_page structures
* representing these pages will be created. The vm_page structures
* are required for promotion of the corresponding kernel virtual
* addresses to superpage mappings.
*/
vm_phys_add_seg(KPTphys, KPTphys + ptoa(nkpt));
virtual_avail = (vm_offset_t) KERNBASE + *firstaddr;
virtual_avail = pmap_kmem_choose(virtual_avail);

9
sys/i386/i386/pmap.c
View File

@ -374,6 +374,15 @@ pmap_bootstrap(vm_paddr_t firstaddr)
struct sysmaps *sysmaps;
int i;
/*
* Add a physical memory segment (vm_phys_seg) corresponding to the
* preallocated kernel page table pages so that vm_page structures
* representing these pages will be created. The vm_page structures
* are required for promotion of the corresponding kernel virtual
* addresses to superpage mappings.
*/
vm_phys_add_seg(KPTphys, KPTphys + ptoa(nkpt));
/*
* Initialize the first available kernel virtual address. However,
* using "firstaddr" may waste a few pages of the kernel virtual

8
sys/i386/include/vmparam.h
View File

@ -64,9 +64,15 @@
#endif
/*
* The physical address space is densely populated.
* Choose between DENSE and SPARSE based on whether lower execution time or
* lower kernel address space consumption is desired. Under PAE, kernel
* address space is often in short supply.
*/
#ifdef PAE
#define VM_PHYSSEG_SPARSE
#else
#define VM_PHYSSEG_DENSE
#endif
/*
* The number of PHYSSEG entries must be one greater than the number

29
sys/vm/vm_page.c
View File

@ -304,9 +304,23 @@ vm_page_startup(vm_offset_t vaddr)
phys_avail[i + 1] = trunc_page(phys_avail[i + 1]);
}
#ifdef XEN
/*
* There is no obvious reason why i386 PV Xen needs vm_page structs
* created for these pseudo-physical addresses. XXX
*/
vm_phys_add_seg(0, phys_avail[0]);
#endif
low_water = phys_avail[0];
high_water = phys_avail[1];
for (i = 0; i < vm_phys_nsegs; i++) {
if (vm_phys_segs[i].start < low_water)
low_water = vm_phys_segs[i].start;
if (vm_phys_segs[i].end > high_water)
high_water = vm_phys_segs[i].end;
}
for (i = 0; phys_avail[i + 1]; i += 2) {
vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
@ -320,10 +334,6 @@ vm_page_startup(vm_offset_t vaddr)
high_water = phys_avail[i + 1];
}
#ifdef XEN
low_water = 0;
#endif
end = phys_avail[biggestone+1];
/*
@ -391,6 +401,10 @@ vm_page_startup(vm_offset_t vaddr)
first_page = low_water / PAGE_SIZE;
#ifdef VM_PHYSSEG_SPARSE
page_range = 0;
for (i = 0; i < vm_phys_nsegs; i++) {
page_range += atop(vm_phys_segs[i].end -
vm_phys_segs[i].start);
}
for (i = 0; phys_avail[i + 1] != 0; i += 2)
page_range += atop(phys_avail[i + 1] - phys_avail[i]);
#elif defined(VM_PHYSSEG_DENSE)
@ -432,6 +446,13 @@ vm_page_startup(vm_offset_t vaddr)
#endif
phys_avail[biggestone + 1] = new_end;
/*
* Add physical memory segments corresponding to the available
* physical pages.
*/
for (i = 0; phys_avail[i + 1] != 0; i += 2)
vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]);
/*
* Clear all of the page structures
*/

103
sys/vm/vm_phys.c
View File

@ -301,29 +301,19 @@ static void
_vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int flind, int domain)
{
struct vm_phys_seg *seg;
#ifdef VM_PHYSSEG_SPARSE
long pages;
int segind;
pages = 0;
for (segind = 0; segind < vm_phys_nsegs; segind++) {
seg = &vm_phys_segs[segind];
pages += atop(seg->end - seg->start);
}
#endif
KASSERT(vm_phys_nsegs < VM_PHYSSEG_MAX,
("vm_phys_create_seg: increase VM_PHYSSEG_MAX"));
KASSERT(domain < vm_ndomains,
("vm_phys_create_seg: invalid domain provided"));
seg = &vm_phys_segs[vm_phys_nsegs++];
while (seg > vm_phys_segs && (seg - 1)->start >= end) {
*seg = *(seg - 1);
seg--;
}
seg->start = start;
seg->end = end;
seg->domain = domain;
#ifdef VM_PHYSSEG_SPARSE
seg->first_page = &vm_page_array[pages];
#else
seg->first_page = PHYS_TO_VM_PAGE(start);
#endif
seg->free_queues = &vm_phys_free_queues[domain][flind];
}
@ -356,6 +346,45 @@ vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int flind)
}
}
/*
* Add a physical memory segment.
*/
void
vm_phys_add_seg(vm_paddr_t start, vm_paddr_t end)
{
KASSERT((start & PAGE_MASK) == 0,
("vm_phys_define_seg: start is not page aligned"));
KASSERT((end & PAGE_MASK) == 0,
("vm_phys_define_seg: end is not page aligned"));
#ifdef VM_FREELIST_ISADMA
if (start < 16777216) {
if (end > 16777216) {
vm_phys_create_seg(start, 16777216,
VM_FREELIST_ISADMA);
vm_phys_create_seg(16777216, end, VM_FREELIST_DEFAULT);
} else
vm_phys_create_seg(start, end, VM_FREELIST_ISADMA);
if (VM_FREELIST_ISADMA >= vm_nfreelists)
vm_nfreelists = VM_FREELIST_ISADMA + 1;
} else
#endif
#ifdef VM_FREELIST_HIGHMEM
if (end > VM_HIGHMEM_ADDRESS) {
if (start < VM_HIGHMEM_ADDRESS) {
vm_phys_create_seg(start, VM_HIGHMEM_ADDRESS,
VM_FREELIST_DEFAULT);
vm_phys_create_seg(VM_HIGHMEM_ADDRESS, end,
VM_FREELIST_HIGHMEM);
} else
vm_phys_create_seg(start, end, VM_FREELIST_HIGHMEM);
if (VM_FREELIST_HIGHMEM >= vm_nfreelists)
vm_nfreelists = VM_FREELIST_HIGHMEM + 1;
} else
#endif
vm_phys_create_seg(start, end, VM_FREELIST_DEFAULT);
}
/*
* Initialize the physical memory allocator.
*/
@ -363,41 +392,23 @@ void
vm_phys_init(void)
{
struct vm_freelist *fl;
int dom, flind, i, oind, pind;
struct vm_phys_seg *seg;
#ifdef VM_PHYSSEG_SPARSE
long pages;
#endif
int dom, flind, oind, pind, segind;
for (i = 0; phys_avail[i + 1] != 0; i += 2) {
#ifdef VM_FREELIST_ISADMA
if (phys_avail[i] < 16777216) {
if (phys_avail[i + 1] > 16777216) {
vm_phys_create_seg(phys_avail[i], 16777216,
VM_FREELIST_ISADMA);
vm_phys_create_seg(16777216, phys_avail[i + 1],
VM_FREELIST_DEFAULT);
} else {
vm_phys_create_seg(phys_avail[i],
phys_avail[i + 1], VM_FREELIST_ISADMA);
}
if (VM_FREELIST_ISADMA >= vm_nfreelists)
vm_nfreelists = VM_FREELIST_ISADMA + 1;
} else
#ifdef VM_PHYSSEG_SPARSE
pages = 0;
#endif
#ifdef VM_FREELIST_HIGHMEM
if (phys_avail[i + 1] > VM_HIGHMEM_ADDRESS) {
if (phys_avail[i] < VM_HIGHMEM_ADDRESS) {
vm_phys_create_seg(phys_avail[i],
VM_HIGHMEM_ADDRESS, VM_FREELIST_DEFAULT);
vm_phys_create_seg(VM_HIGHMEM_ADDRESS,
phys_avail[i + 1], VM_FREELIST_HIGHMEM);
} else {
vm_phys_create_seg(phys_avail[i],
phys_avail[i + 1], VM_FREELIST_HIGHMEM);
}
if (VM_FREELIST_HIGHMEM >= vm_nfreelists)
vm_nfreelists = VM_FREELIST_HIGHMEM + 1;
} else
for (segind = 0; segind < vm_phys_nsegs; segind++) {
seg = &vm_phys_segs[segind];
#ifdef VM_PHYSSEG_SPARSE
seg->first_page = &vm_page_array[pages];
pages += atop(seg->end - seg->start);
#else
seg->first_page = PHYS_TO_VM_PAGE(seg->start);
#endif
vm_phys_create_seg(phys_avail[i], phys_avail[i + 1],
VM_FREELIST_DEFAULT);
}
for (dom = 0; dom < vm_ndomains; dom++) {
for (flind = 0; flind < vm_nfreelists; flind++) {

1
sys/vm/vm_phys.h
View File

@ -69,6 +69,7 @@ extern int vm_phys_nsegs;
* The following functions are only to be used by the virtual memory system.
*/
void vm_phys_add_page(vm_paddr_t pa);
void vm_phys_add_seg(vm_paddr_t start, vm_paddr_t end);
vm_page_t vm_phys_alloc_contig(u_long npages, vm_paddr_t low, vm_paddr_t high,
u_long alignment, vm_paddr_t boundary);
vm_page_t vm_phys_alloc_freelist_pages(int flind, int pool, int order);