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[PATCH] mm: powerpc ptlock comments

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Update comments (only) on page_table_lock and mmap_sem in arch/powerpc.
Removed the comment on page_table_lock from hash_huge_page: since it's no
longer taking page_table_lock itself, it's irrelevant whether others are; but
how it is safe (even against huge file truncation?) I can't say.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins 2005-11-23 13:37:39 -08:00 committed by Linus Torvalds
parent cc3327e7df
commit 01edcd891c
4 changed files with 10 additions and 6 deletions
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4
arch/powerpc/mm/hugetlbpage.c
View file

@ -754,9 +754,7 @@ repeat:
}
/*
* No need to use ldarx/stdcx here because all who
* might be updating the pte will hold the
* page_table_lock
* No need to use ldarx/stdcx here
*/
*ptep = __pte(new_pte & ~_PAGE_BUSY);

2
arch/powerpc/mm/mem.c
View file

@ -495,7 +495,7 @@ EXPORT_SYMBOL(flush_icache_user_range);
* We use it to preload an HPTE into the hash table corresponding to
* the updated linux PTE.
*
* This must always be called with the mm->page_table_lock held
* This must always be called with the pte lock held.
*/
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
pte_t pte)

6
arch/powerpc/mm/tlb_32.c
View file

@ -149,6 +149,12 @@ void flush_tlb_mm(struct mm_struct *mm)
return;
}
/*
* It is safe to go down the mm's list of vmas when called
* from dup_mmap, holding mmap_sem. It would also be safe from
* unmap_region or exit_mmap, but not from vmtruncate on SMP -
* but it seems dup_mmap is the only SMP case which gets here.
*/
for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
FINISH_FLUSH;

4
arch/powerpc/mm/tlb_64.c
View file

@ -95,7 +95,7 @@ static void pte_free_submit(struct pte_freelist_batch *batch)
void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf)
{
/* This is safe as we are holding page_table_lock */
/* This is safe since tlb_gather_mmu has disabled preemption */
cpumask_t local_cpumask = cpumask_of_cpu(smp_processor_id());
struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);
@ -206,7 +206,7 @@ void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
void pte_free_finish(void)
{
/* This is safe as we are holding page_table_lock */
/* This is safe since tlb_gather_mmu has disabled preemption */
struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);
if (*batchp == NULL)