| Message ID | c0b2c70cf5c7a036c560d9ddba7b2904b84ab9ab.1724441678.git.lorenzo.stoakes@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: remove vma_merge() | expand |
* Lorenzo Stoakes <lorenzo.stoakes@oracle.com> [240823 16:07]: > Both can_vma_merge_before() and can_vma_merge_after() are invoked after > checking for compatible VMA NUMA policy, we can simply move this to > is_mergeable_vma() and abstract this altogether. > > In mmap_region() we set vmg->policy to NULL, so the policy comparisons > checked in can_vma_merge_before() and can_vma_merge_after() are exactly > equivalent to !vma_policy(vmg.next) and !vma_policy(vmg.prev). > > Equally, in do_brk_flags(), vmg->policy is NULL, so the > can_vma_merge_after() is checking !vma_policy(vma), as we set vmg.prev to > vma. > > In vma_merge(), we compare prev and next policies with vmg->policy before > checking can_vma_merge_after() and can_vma_merge_before() respectively, > which this patch causes to be checked in precisely the same way. > > This therefore maintains precisely the same logic as before, only now > abstracted into is_mergeable_vma(). > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> > Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> > --- > mm/mmap.c | 8 +++----- > mm/vma.c | 9 ++++----- > 2 files changed, 7 insertions(+), 10 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index 4066c0444495..c72f50feb98a 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1423,8 +1423,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > > /* Attempt to expand an old mapping */ > /* Check next */ > - if (next && next->vm_start == end && !vma_policy(next) && > - can_vma_merge_before(&vmg)) { > + if (next && next->vm_start == end && can_vma_merge_before(&vmg)) { It occurs to me that we could use the vma iterators index/last to check the limits prior to needing to move at all.. but I'll leave that for future work. > merge_end = next->vm_end; > vma = next; > vmg.pgoff = next->vm_pgoff - pglen; > @@ -1438,8 +1437,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > } > > /* Check prev */ > - if (prev && prev->vm_end == addr && !vma_policy(prev) && > - can_vma_merge_after(&vmg)) { > + if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) { > merge_start = prev->vm_start; > vma = prev; > vmg.pgoff = prev->vm_pgoff; > @@ -1778,7 +1776,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, > * Expand the existing vma if possible; Note that singular lists do not > * occur after forking, so the expand will only happen on new VMAs. > */ > - if (vma && vma->vm_end == addr && !vma_policy(vma)) { > + if (vma && vma->vm_end == addr) { > VMG_STATE(vmg, mm, vmi, addr, addr + len, flags, PHYS_PFN(addr)); > > vmg.prev = vma; > diff --git a/mm/vma.c b/mm/vma.c > index 74c627ff0313..b1ec412fac7f 100644 > --- a/mm/vma.c > +++ b/mm/vma.c > @@ -19,6 +19,8 @@ static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_nex > */ > bool may_remove_vma = merge_next; > > + if (!mpol_equal(vmg->policy, vma_policy(vma))) > + return false; Should we ensure there is any vma to check here? Maybe just an assert? > /* > * VM_SOFTDIRTY should not prevent from VMA merging, if we > * match the flags but dirty bit -- the caller should mark > @@ -1058,17 +1060,14 @@ static struct vm_area_struct *vma_merge(struct vma_merge_struct *vmg) > vma_pgoff = prev->vm_pgoff; > > /* Can we merge the predecessor? */ > - if (addr == prev->vm_end && mpol_equal(vma_policy(prev), vmg->policy) > - && can_vma_merge_after(vmg)) { > - > + if (addr == prev->vm_end && can_vma_merge_after(vmg)) { > merge_prev = true; > vma_prev(vmg->vmi); > } > } > > /* Can we merge the successor? */ > - if (next && mpol_equal(vmg->policy, vma_policy(next)) && > - can_vma_merge_before(vmg)) { > + if (next && can_vma_merge_before(vmg)) { > merge_next = true; > } > > -- > 2.46.0 >
diff --git a/mm/mmap.c b/mm/mmap.c index 4066c0444495..c72f50feb98a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1423,8 +1423,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* Attempt to expand an old mapping */ /* Check next */ - if (next && next->vm_start == end && !vma_policy(next) && - can_vma_merge_before(&vmg)) { + if (next && next->vm_start == end && can_vma_merge_before(&vmg)) { merge_end = next->vm_end; vma = next; vmg.pgoff = next->vm_pgoff - pglen; @@ -1438,8 +1437,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, } /* Check prev */ - if (prev && prev->vm_end == addr && !vma_policy(prev) && - can_vma_merge_after(&vmg)) { + if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) { merge_start = prev->vm_start; vma = prev; vmg.pgoff = prev->vm_pgoff; @@ -1778,7 +1776,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, * Expand the existing vma if possible; Note that singular lists do not * occur after forking, so the expand will only happen on new VMAs. */ - if (vma && vma->vm_end == addr && !vma_policy(vma)) { + if (vma && vma->vm_end == addr) { VMG_STATE(vmg, mm, vmi, addr, addr + len, flags, PHYS_PFN(addr)); vmg.prev = vma; diff --git a/mm/vma.c b/mm/vma.c index 74c627ff0313..b1ec412fac7f 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -19,6 +19,8 @@ static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_nex */ bool may_remove_vma = merge_next; + if (!mpol_equal(vmg->policy, vma_policy(vma))) + return false; /* * VM_SOFTDIRTY should not prevent from VMA merging, if we * match the flags but dirty bit -- the caller should mark @@ -1058,17 +1060,14 @@ static struct vm_area_struct *vma_merge(struct vma_merge_struct *vmg) vma_pgoff = prev->vm_pgoff; /* Can we merge the predecessor? */ - if (addr == prev->vm_end && mpol_equal(vma_policy(prev), vmg->policy) - && can_vma_merge_after(vmg)) { - + if (addr == prev->vm_end && can_vma_merge_after(vmg)) { merge_prev = true; vma_prev(vmg->vmi); } } /* Can we merge the successor? */ - if (next && mpol_equal(vmg->policy, vma_policy(next)) && - can_vma_merge_before(vmg)) { + if (next && can_vma_merge_before(vmg)) { merge_next = true; }