mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 15:16:39 +07:00
89a77915e0
Mostly mirrors the s390 logic, as unlike x86 we don't need the SetPageReferenced() bits. On sparc64 we also lack a user/privileged bit in the huge PMDs. In order to make this work for THP and non-THP builds, some header file adjustments were necessary. Namely, provide the PMD_HUGE_* bit defines and the pmd_large() inline unconditionally rather than protected by TRANSPARENT_HUGEPAGE. Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
239 lines
5.2 KiB
C
239 lines
5.2 KiB
C
/*
|
|
* Lockless get_user_pages_fast for sparc, cribbed from powerpc
|
|
*
|
|
* Copyright (C) 2008 Nick Piggin
|
|
* Copyright (C) 2008 Novell Inc.
|
|
*/
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/vmstat.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/rwsem.h>
|
|
#include <asm/pgtable.h>
|
|
|
|
/*
|
|
* The performance critical leaf functions are made noinline otherwise gcc
|
|
* inlines everything into a single function which results in too much
|
|
* register pressure.
|
|
*/
|
|
static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
|
|
unsigned long end, int write, struct page **pages, int *nr)
|
|
{
|
|
unsigned long mask, result;
|
|
pte_t *ptep;
|
|
|
|
if (tlb_type == hypervisor) {
|
|
result = _PAGE_PRESENT_4V|_PAGE_P_4V;
|
|
if (write)
|
|
result |= _PAGE_WRITE_4V;
|
|
} else {
|
|
result = _PAGE_PRESENT_4U|_PAGE_P_4U;
|
|
if (write)
|
|
result |= _PAGE_WRITE_4U;
|
|
}
|
|
mask = result | _PAGE_SPECIAL;
|
|
|
|
ptep = pte_offset_kernel(&pmd, addr);
|
|
do {
|
|
struct page *page, *head;
|
|
pte_t pte = *ptep;
|
|
|
|
if ((pte_val(pte) & mask) != result)
|
|
return 0;
|
|
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
|
|
|
|
/* The hugepage case is simplified on sparc64 because
|
|
* we encode the sub-page pfn offsets into the
|
|
* hugepage PTEs. We could optimize this in the future
|
|
* use page_cache_add_speculative() for the hugepage case.
|
|
*/
|
|
page = pte_page(pte);
|
|
head = compound_head(page);
|
|
if (!page_cache_get_speculative(head))
|
|
return 0;
|
|
if (unlikely(pte_val(pte) != pte_val(*ptep))) {
|
|
put_page(head);
|
|
return 0;
|
|
}
|
|
if (head != page)
|
|
get_huge_page_tail(page);
|
|
|
|
pages[*nr] = page;
|
|
(*nr)++;
|
|
} while (ptep++, addr += PAGE_SIZE, addr != end);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
|
|
unsigned long end, int write, struct page **pages,
|
|
int *nr)
|
|
{
|
|
struct page *head, *page, *tail;
|
|
u32 mask;
|
|
int refs;
|
|
|
|
mask = PMD_HUGE_PRESENT;
|
|
if (write)
|
|
mask |= PMD_HUGE_WRITE;
|
|
if ((pmd_val(pmd) & mask) != mask)
|
|
return 0;
|
|
|
|
refs = 0;
|
|
head = pmd_page(pmd);
|
|
page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
|
|
tail = page;
|
|
do {
|
|
VM_BUG_ON(compound_head(page) != head);
|
|
pages[*nr] = page;
|
|
(*nr)++;
|
|
page++;
|
|
refs++;
|
|
} while (addr += PAGE_SIZE, addr != end);
|
|
|
|
if (!page_cache_add_speculative(head, refs)) {
|
|
*nr -= refs;
|
|
return 0;
|
|
}
|
|
|
|
if (unlikely(pmd_val(pmd) != pmd_val(*pmdp))) {
|
|
*nr -= refs;
|
|
while (refs--)
|
|
put_page(head);
|
|
return 0;
|
|
}
|
|
|
|
/* Any tail page need their mapcount reference taken before we
|
|
* return.
|
|
*/
|
|
while (refs--) {
|
|
if (PageTail(tail))
|
|
get_huge_page_tail(tail);
|
|
tail++;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
|
|
int write, struct page **pages, int *nr)
|
|
{
|
|
unsigned long next;
|
|
pmd_t *pmdp;
|
|
|
|
pmdp = pmd_offset(&pud, addr);
|
|
do {
|
|
pmd_t pmd = *pmdp;
|
|
|
|
next = pmd_addr_end(addr, end);
|
|
if (pmd_none(pmd) || pmd_trans_splitting(pmd))
|
|
return 0;
|
|
if (unlikely(pmd_large(pmd))) {
|
|
if (!gup_huge_pmd(pmdp, pmd, addr, next,
|
|
write, pages, nr))
|
|
return 0;
|
|
} else if (!gup_pte_range(pmd, addr, next, write,
|
|
pages, nr))
|
|
return 0;
|
|
} while (pmdp++, addr = next, addr != end);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
|
|
int write, struct page **pages, int *nr)
|
|
{
|
|
unsigned long next;
|
|
pud_t *pudp;
|
|
|
|
pudp = pud_offset(&pgd, addr);
|
|
do {
|
|
pud_t pud = *pudp;
|
|
|
|
next = pud_addr_end(addr, end);
|
|
if (pud_none(pud))
|
|
return 0;
|
|
if (!gup_pmd_range(pud, addr, next, write, pages, nr))
|
|
return 0;
|
|
} while (pudp++, addr = next, addr != end);
|
|
|
|
return 1;
|
|
}
|
|
|
|
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
|
|
struct page **pages)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long addr, len, end;
|
|
unsigned long next;
|
|
pgd_t *pgdp;
|
|
int nr = 0;
|
|
|
|
start &= PAGE_MASK;
|
|
addr = start;
|
|
len = (unsigned long) nr_pages << PAGE_SHIFT;
|
|
end = start + len;
|
|
|
|
/*
|
|
* XXX: batch / limit 'nr', to avoid large irq off latency
|
|
* needs some instrumenting to determine the common sizes used by
|
|
* important workloads (eg. DB2), and whether limiting the batch size
|
|
* will decrease performance.
|
|
*
|
|
* It seems like we're in the clear for the moment. Direct-IO is
|
|
* the main guy that batches up lots of get_user_pages, and even
|
|
* they are limited to 64-at-a-time which is not so many.
|
|
*/
|
|
/*
|
|
* This doesn't prevent pagetable teardown, but does prevent
|
|
* the pagetables from being freed on sparc.
|
|
*
|
|
* So long as we atomically load page table pointers versus teardown,
|
|
* we can follow the address down to the the page and take a ref on it.
|
|
*/
|
|
local_irq_disable();
|
|
|
|
pgdp = pgd_offset(mm, addr);
|
|
do {
|
|
pgd_t pgd = *pgdp;
|
|
|
|
next = pgd_addr_end(addr, end);
|
|
if (pgd_none(pgd))
|
|
goto slow;
|
|
if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
|
|
goto slow;
|
|
} while (pgdp++, addr = next, addr != end);
|
|
|
|
local_irq_enable();
|
|
|
|
VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT);
|
|
return nr;
|
|
|
|
{
|
|
int ret;
|
|
|
|
slow:
|
|
local_irq_enable();
|
|
|
|
/* Try to get the remaining pages with get_user_pages */
|
|
start += nr << PAGE_SHIFT;
|
|
pages += nr;
|
|
|
|
down_read(&mm->mmap_sem);
|
|
ret = get_user_pages(current, mm, start,
|
|
(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);
|
|
up_read(&mm->mmap_sem);
|
|
|
|
/* Have to be a bit careful with return values */
|
|
if (nr > 0) {
|
|
if (ret < 0)
|
|
ret = nr;
|
|
else
|
|
ret += nr;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
}
|