On Sun 09-08-15 01:22:51, Eric B Munson wrote: > Extending the mlock system call is very difficult because it currently > does not take a flags argument. A later patch in this set will extend > mlock to support a middle ground between pages that are locked and > faulted in immediately and unlocked pages. To pave the way for the new > system call, the code needs some reorganization so that all the actual > entry point handles is checking input and translating to VMA flags.
OK, I find the reorganized code more readable. > Signed-off-by: Eric B Munson <[email protected]> > Acked-by: Kirill A. Shutemov <[email protected]> > Acked-by: Vlastimil Babka <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Vlastimil Babka <[email protected]> > Cc: "Kirill A. Shutemov" <[email protected]> > Cc: [email protected] > Cc: [email protected] Acked-by: Michal Hocko <[email protected]> > --- > mm/mlock.c | 30 +++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/mm/mlock.c b/mm/mlock.c > index 6fd2cf1..5692ee5 100644 > --- a/mm/mlock.c > +++ b/mm/mlock.c > @@ -553,7 +553,8 @@ out: > return ret; > } > > -static int do_mlock(unsigned long start, size_t len, int on) > +static int apply_vma_lock_flags(unsigned long start, size_t len, > + vm_flags_t flags) > { > unsigned long nstart, end, tmp; > struct vm_area_struct * vma, * prev; > @@ -575,14 +576,11 @@ static int do_mlock(unsigned long start, size_t len, > int on) > prev = vma; > > for (nstart = start ; ; ) { > - vm_flags_t newflags; > - > - /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ > + vm_flags_t newflags = vma->vm_flags & ~VM_LOCKED; > > - newflags = vma->vm_flags & ~VM_LOCKED; > - if (on) > - newflags |= VM_LOCKED; > + newflags |= flags; > > + /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ > tmp = vma->vm_end; > if (tmp > end) > tmp = end; > @@ -604,7 +602,7 @@ static int do_mlock(unsigned long start, size_t len, int > on) > return error; > } > > -SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) > +static int do_mlock(unsigned long start, size_t len, vm_flags_t flags) > { > unsigned long locked; > unsigned long lock_limit; > @@ -628,7 +626,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) > > /* check against resource limits */ > if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) > - error = do_mlock(start, len, 1); > + error = apply_vma_lock_flags(start, len, flags); > > up_write(¤t->mm->mmap_sem); > if (error) > @@ -640,6 +638,11 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) > return 0; > } > > +SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) > +{ > + return do_mlock(start, len, VM_LOCKED); > +} > + > SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) > { > int ret; > @@ -648,13 +651,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, > len) > start &= PAGE_MASK; > > down_write(¤t->mm->mmap_sem); > - ret = do_mlock(start, len, 0); > + ret = apply_vma_lock_flags(start, len, 0); > up_write(¤t->mm->mmap_sem); > > return ret; > } > > -static int do_mlockall(int flags) > +static int apply_mlockall_flags(int flags) > { > struct vm_area_struct * vma, * prev = NULL; > > @@ -662,6 +665,7 @@ static int do_mlockall(int flags) > current->mm->def_flags |= VM_LOCKED; > else > current->mm->def_flags &= ~VM_LOCKED; > + > if (flags == MCL_FUTURE) > goto out; > > @@ -703,7 +707,7 @@ SYSCALL_DEFINE1(mlockall, int, flags) > > if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || > capable(CAP_IPC_LOCK)) > - ret = do_mlockall(flags); > + ret = apply_mlockall_flags(flags); > up_write(¤t->mm->mmap_sem); > if (!ret && (flags & MCL_CURRENT)) > mm_populate(0, TASK_SIZE); > @@ -716,7 +720,7 @@ SYSCALL_DEFINE0(munlockall) > int ret; > > down_write(¤t->mm->mmap_sem); > - ret = do_mlockall(0); > + ret = apply_mlockall_flags(0); > up_write(¤t->mm->mmap_sem); > return ret; > } > -- > 1.9.1 -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
