mirror of
https://github.com/brain-hackers/linux-brain.git
synced 2024-06-09 07:16:21 +09:00
13224794cb
Patch series "mm: remove quicklist page table caches". A while ago Nicholas proposed to remove quicklist page table caches [1]. I've rebased his patch on the curren upstream and switched ia64 and sh to use generic versions of PTE allocation. [1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com This patch (of 3): Remove page table allocator "quicklists". These have been around for a long time, but have not got much traction in the last decade and are only used on ia64 and sh architectures. The numbers in the initial commit look interesting but probably don't apply anymore. If anybody wants to resurrect this it's in the git history, but it's unhelpful to have this code and divergent allocator behaviour for minor archs. Also it might be better to instead make more general improvements to page allocator if this is still so slow. Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
102 lines
2.8 KiB
C
102 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Page table support for the Hexagon architecture
|
|
*
|
|
* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
|
|
*/
|
|
|
|
#ifndef _ASM_PGALLOC_H
|
|
#define _ASM_PGALLOC_H
|
|
|
|
#include <asm/mem-layout.h>
|
|
#include <asm/atomic.h>
|
|
|
|
#include <asm-generic/pgalloc.h> /* for pte_{alloc,free}_one */
|
|
|
|
extern unsigned long long kmap_generation;
|
|
|
|
/*
|
|
* Page table creation interface
|
|
*/
|
|
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
|
|
{
|
|
pgd_t *pgd;
|
|
|
|
pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
|
|
|
|
/*
|
|
* There may be better ways to do this, but to ensure
|
|
* that new address spaces always contain the kernel
|
|
* base mapping, and to ensure that the user area is
|
|
* initially marked invalid, initialize the new map
|
|
* map with a copy of the kernel's persistent map.
|
|
*/
|
|
|
|
memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
|
|
mm->context.generation = kmap_generation;
|
|
|
|
/* Physical version is what is passed to virtual machine on switch */
|
|
mm->context.ptbase = __pa(pgd);
|
|
|
|
return pgd;
|
|
}
|
|
|
|
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
|
|
{
|
|
free_page((unsigned long) pgd);
|
|
}
|
|
|
|
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
|
|
pgtable_t pte)
|
|
{
|
|
/*
|
|
* Conveniently, zero in 3 LSB means indirect 4K page table.
|
|
* Not so convenient when you're trying to vary the page size.
|
|
*/
|
|
set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
|
|
HEXAGON_L1_PTE_SIZE));
|
|
}
|
|
|
|
/*
|
|
* Other architectures seem to have ways of making all processes
|
|
* share the same pmd's for their kernel mappings, but the v0.3
|
|
* Hexagon VM spec has a "monolithic" L1 table for user and kernel
|
|
* segments. We track "generations" of the kernel map to minimize
|
|
* overhead, and update the "slave" copies of the kernel mappings
|
|
* as part of switch_mm. However, we still need to update the
|
|
* kernel map of the active thread who's calling pmd_populate_kernel...
|
|
*/
|
|
static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
|
|
pte_t *pte)
|
|
{
|
|
extern spinlock_t kmap_gen_lock;
|
|
pmd_t *ppmd;
|
|
int pmdindex;
|
|
|
|
spin_lock(&kmap_gen_lock);
|
|
kmap_generation++;
|
|
mm->context.generation = kmap_generation;
|
|
current->active_mm->context.generation = kmap_generation;
|
|
spin_unlock(&kmap_gen_lock);
|
|
|
|
set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
|
|
|
|
/*
|
|
* Now the "slave" copy of the current thread.
|
|
* This is pointer arithmetic, not byte addresses!
|
|
*/
|
|
pmdindex = (pgd_t *)pmd - mm->pgd;
|
|
ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
|
|
set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
|
|
if (pmdindex > max_kernel_seg)
|
|
max_kernel_seg = pmdindex;
|
|
}
|
|
|
|
#define __pte_free_tlb(tlb, pte, addr) \
|
|
do { \
|
|
pgtable_page_dtor((pte)); \
|
|
tlb_remove_page((tlb), (pte)); \
|
|
} while (0)
|
|
|
|
#endif
|