| Message ID | 20240822192543.3359552-22-Liam.Howlett@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Avoid MAP_FIXED gap exposure | expand |
On Thu, Aug 22, 2024 at 03:25:43PM GMT, Liam R. Howlett wrote: > From: "Liam R. Howlett" <Liam.Howlett@Oracle.com> > > The vma_munmap_struct has a hole of 4 bytes and pushes the struct to > three cachelines. Relocating the three booleans upwards allows for the > struct to only use two cachelines (as reported by pahole on amd64). > > Before: > struct vma_munmap_struct { > struct vma_iterator * vmi; /* 0 8 */ > struct vm_area_struct * vma; /* 8 8 */ > struct vm_area_struct * prev; /* 16 8 */ > struct vm_area_struct * next; /* 24 8 */ > struct list_head * uf; /* 32 8 */ > long unsigned int start; /* 40 8 */ > long unsigned int end; /* 48 8 */ > long unsigned int unmap_start; /* 56 8 */ > /* --- cacheline 1 boundary (64 bytes) --- */ > long unsigned int unmap_end; /* 64 8 */ > int vma_count; /* 72 4 */ > > /* XXX 4 bytes hole, try to pack */ > > long unsigned int nr_pages; /* 80 8 */ > long unsigned int locked_vm; /* 88 8 */ > long unsigned int nr_accounted; /* 96 8 */ > long unsigned int exec_vm; /* 104 8 */ > long unsigned int stack_vm; /* 112 8 */ > long unsigned int data_vm; /* 120 8 */ > /* --- cacheline 2 boundary (128 bytes) --- */ > bool unlock; /* 128 1 */ > bool clear_ptes; /* 129 1 */ > bool closed_vm_ops; /* 130 1 */ > > /* size: 136, cachelines: 3, members: 19 */ > /* sum members: 127, holes: 1, sum holes: 4 */ > /* padding: 5 */ > /* last cacheline: 8 bytes */ > }; > > After: > struct vma_munmap_struct { > struct vma_iterator * vmi; /* 0 8 */ > struct vm_area_struct * vma; /* 8 8 */ > struct vm_area_struct * prev; /* 16 8 */ > struct vm_area_struct * next; /* 24 8 */ > struct list_head * uf; /* 32 8 */ > long unsigned int start; /* 40 8 */ > long unsigned int end; /* 48 8 */ > long unsigned int unmap_start; /* 56 8 */ > /* --- cacheline 1 boundary (64 bytes) --- */ > long unsigned int unmap_end; /* 64 8 */ > int vma_count; /* 72 4 */ > bool unlock; /* 76 1 */ > bool clear_ptes; /* 77 1 */ > bool closed_vm_ops; /* 78 1 */ > > /* XXX 1 byte hole, try to pack */ > > long unsigned int nr_pages; /* 80 8 */ > long unsigned int locked_vm; /* 88 8 */ > long unsigned int nr_accounted; /* 96 8 */ > long unsigned int exec_vm; /* 104 8 */ > long unsigned int stack_vm; /* 112 8 */ > long unsigned int data_vm; /* 120 8 */ > > /* size: 128, cachelines: 2, members: 19 */ > /* sum members: 127, holes: 1, sum holes: 1 */ > }; > > Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> > --- > mm/vma.h | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/mm/vma.h b/mm/vma.h > index 7047fedce459..c774642697a0 100644 > --- a/mm/vma.h > +++ b/mm/vma.h > @@ -40,15 +40,16 @@ struct vma_munmap_struct { > unsigned long unmap_start; /* Unmap PTE start */ > unsigned long unmap_end; /* Unmap PTE end */ > int vma_count; /* Number of vmas that will be removed */ > + bool unlock; /* Unlock after the munmap */ > + bool clear_ptes; /* If there are outstanding PTE to be cleared */ > + bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ > + /* 1 byte hole */ > unsigned long nr_pages; /* Number of pages being removed */ > unsigned long locked_vm; /* Number of locked pages */ > unsigned long nr_accounted; /* Number of VM_ACCOUNT pages */ > unsigned long exec_vm; > unsigned long stack_vm; > unsigned long data_vm; > - bool unlock; /* Unlock after the munmap */ > - bool clear_ptes; /* If there are outstanding PTE to be cleared */ > - bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ > }; > > #ifdef CONFIG_DEBUG_VM_MAPLE_TREE > -- > 2.43.0 >
diff --git a/mm/vma.h b/mm/vma.h index 7047fedce459..c774642697a0 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -40,15 +40,16 @@ struct vma_munmap_struct { unsigned long unmap_start; /* Unmap PTE start */ unsigned long unmap_end; /* Unmap PTE end */ int vma_count; /* Number of vmas that will be removed */ + bool unlock; /* Unlock after the munmap */ + bool clear_ptes; /* If there are outstanding PTE to be cleared */ + bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ + /* 1 byte hole */ unsigned long nr_pages; /* Number of pages being removed */ unsigned long locked_vm; /* Number of locked pages */ unsigned long nr_accounted; /* Number of VM_ACCOUNT pages */ unsigned long exec_vm; unsigned long stack_vm; unsigned long data_vm; - bool unlock; /* Unlock after the munmap */ - bool clear_ptes; /* If there are outstanding PTE to be cleared */ - bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ }; #ifdef CONFIG_DEBUG_VM_MAPLE_TREE