On Saturday 30 July 2005 18:02, Jeff Dike wrote: > On Thu, Jul 28, 2005 at 08:56:53PM +0200, [EMAIL PROTECTED] wrote: > > As obvious, a "core code nice cleanup" is not a "stability-friendly > > patch" so usual care applies. > > These look reasonable, as they are what we discussed in Ottawa. > > I'll put them in my tree and see if I see any problems. I would > suggest sending these in early after 2.6.13 if they seem OK. Just noticed: you can drop them (except the first, which is a nice cleanup).
set_pte handles that, and include/asm-generic/pgtable.h uses coherently set_pte_at. I've checked UML by examining "grep pte", and either mk_pte or set_pte are used. Exceptions: fixaddr_user_init (but that should be ok as we shouldn't map it actually), pte_modify() (which handles that only for present pages). But pte_modify is used with set_pte, so probably we could as well drop that handling. Also look, on the "set_pte" theme, at the attached patch. I realized this when I needed those lines to work - I was getting a segfault loop. After using set_pte(), things worked. I have now an almost perfectly working implementation of remap_file_pages with protection support. There will probably be some other things to update, like swapping locations, but I can't get this kernel to fail (it's easier to find bugs in the test-program, it grew quite complex). And, I'd like to note, original Ingo's version *DID NOT* work properly (it was not safe against swapout, it didn't allow write-protecting a page successfully). I'm going to clean up the code and write changelogs, to send then the patches for -mm (hoping the page fault scalability patches don't get in the way). -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade
From: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> The PTE returned from handle_mm_fault is already marked as dirty and accessed if needed. Also, since this is not set with set_pte() (which sets NEWPAGE and NEWPROT as needed), this wouldn't work anyway. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]> --- linux-2.6.git-paolo/arch/um/kernel/trap_kern.c | 3 +-- 1 files changed, 1 insertion(+), 2 deletions(-) diff -puN arch/um/kernel/trap_kern.c~uml-avoid-already-done-dirtying arch/um/kernel/trap_kern.c --- linux-2.6.git/arch/um/kernel/trap_kern.c~uml-avoid-already-done-dirtying 2005-08-10 19:21:13.000000000 +0200 +++ linux-2.6.git-paolo/arch/um/kernel/trap_kern.c 2005-08-10 19:21:13.000000000 +0200 @@ -83,8 +83,7 @@ survive: pte = pte_offset_kernel(pmd, address); } while(!pte_present(*pte)); err = 0; - *pte = pte_mkyoung(*pte); - if(pte_write(*pte)) *pte = pte_mkdirty(*pte); + WARN_ON(!pte_young(*pte) || pte_write(*pte) && !pte_dirty(*pte)); flush_tlb_page(vma, address); out: up_read(&mm->mmap_sem); _
