Messages in this thread | | | Date | Sat, 16 Oct 1999 01:16:10 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH] kanoj-mm17-2.3.21 kswapd vma scanning protection |
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Linus Torvalds wrote: > > .. hold a spinlock - we can probably just reuse the > page_table_lock for this to avoid multiple levels of locking > here.. > > file = fget(vma->vm_file); ^^^^^^^ > offset = file->f_offset + (address - vma->vm_start); > flush_tlb_page(vma, address); > spin_unlock(&vma->vm_mm->page_table_lock); > > error = file->f_ops->swapout(file, offset, page); > fput(file); > > ... > > and then the other requirement would be that whenever the vma chain is > physically modified, you also have to hold the page_table_lock. >
What about shm? vma->vm_file is NULL, this would oops. I think that both "prepare for possible vma removal" and the parameters which are passed to ->swapout() should be vma-specific: what about a vm_ops->swapprepare()? This function should not allocate memory, ie parameter passing should be stack based:
<<<<< mm.h struct private_data { void* private[4]; }; struct vm_ops { ... void (*swapprepare)(struct vm_area_struct * vma, struct page * page, struct private_data * info); void (*swapout)(struct private_data * info, struct page* page); ... }; >>>>>>>>> <<<<<<<< vmscan.c
if(vma->vm_ops && vma->vm_ops->swapout) { int error; struct private_data info; void (*swapout)(...);
pte_clear(page_table); swapout = vma->vm_ops->swapout; vma->vm_ops->swapprepare(vma,page,&info); spin_unlock(page_table_lock); flush_tlb_page(); error = swapout(&info,page); ... } >>>>>>>>>>>>>>>>
-- Manfred
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