Messages in this thread | | | Date | Thu, 13 May 2010 17:37:39 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH v3 0/10] Uprobes v3 |
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> > Hrmm, you could do something like the above and use write_protect_page() > along with that lock_page() you do to sync against concurrent faults. It > won't be the fastest code around but it should work I guess.
Okay, thanks for the code.
> > Something like try_to_merge_one_page() in the KSM code: > > write_opcode(struct mm_struct *mm, unsigned long address, void *insn, > int len) > { > down_read(mm->mmap_sem);
[ snipped] > > kunmap_atomic(vaddr_new); > kunmap_atomic(vaddr_old); > > /* XXX: frob mlock state */
I think you are referring to mlock_vma_page() and munlock_vma_page that we have in try_to_merge_one_page(). However mlock_vma_page and munlock_vma_page are not exposed outside mm as they are declared inside mm/internal.h. So do you suggest moving the declarations out of mm/internal.h or have a wrapper function defined in mm/ that could be used by both KSM and uprobes.
> > /* flip pages, do_wp_page() will fail pte_same() and bail */ > err = replace_page(vma, new_page, old_page, orig_pte) > if (err) goto fail_more; > > /* we're done, let 'em rip */ > unlock_page(old_page); > put_page(old_page); > > return; > > fail: > /* XXX: fixup stuff */ > } > > Note that this can fail for fun reasons like O_DIRECT IO, but that > should be very rare indeed on text pages. >
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