| Message ID | 20181023213504.28905-13-igor.stoppa@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | prmem: protected memory | expand |
On Wed, Oct 24, 2018 at 12:34:59AM +0300, Igor Stoppa wrote: > As preparation to using write rare on the nodes of various types of > lists, specify that the fields in the basic data structures must be > aligned to sizeof(void *) > > It is meant to ensure that any static allocation will not cross a page > boundary, to allow pointers to be updated in one step. > > Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com> > CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > CC: Andrew Morton <akpm@linux-foundation.org> > CC: Masahiro Yamada <yamada.masahiro@socionext.com> > CC: Alexey Dobriyan <adobriyan@gmail.com> > CC: Pekka Enberg <penberg@kernel.org> > CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> > CC: Lihao Liang <lianglihao@huawei.com> > CC: linux-kernel@vger.kernel.org > --- > include/linux/types.h | 20 ++++++++++++++++---- > 1 file changed, 16 insertions(+), 4 deletions(-) > > diff --git a/include/linux/types.h b/include/linux/types.h > index 9834e90aa010..53609bbdcf0f 100644 > --- a/include/linux/types.h > +++ b/include/linux/types.h > @@ -183,17 +183,29 @@ typedef struct { > } atomic64_t; > #endif > > +#ifdef CONFIG_PRMEM > struct list_head { > - struct list_head *next, *prev; > -}; > + struct list_head *next __aligned(sizeof(void *)); > + struct list_head *prev __aligned(sizeof(void *)); > +} __aligned(sizeof(void *)); > > -struct hlist_head { > - struct hlist_node *first; > +struct hlist_node { > + struct hlist_node *next __aligned(sizeof(void *)); > + struct hlist_node **pprev __aligned(sizeof(void *)); > +} __aligned(sizeof(void *)); Argh.. are we really supporting platforms that do not naturally align this? If so, which and can't we fix those? Also, if you force alignment on a member, the structure as a whole inherits the largest member alignment. Also, you made something that was simple an unreadable mess without proper justification (ie. you fail to show need).
diff --git a/include/linux/types.h b/include/linux/types.h index 9834e90aa010..53609bbdcf0f 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -183,17 +183,29 @@ typedef struct { } atomic64_t; #endif +#ifdef CONFIG_PRMEM struct list_head { - struct list_head *next, *prev; -}; + struct list_head *next __aligned(sizeof(void *)); + struct list_head *prev __aligned(sizeof(void *)); +} __aligned(sizeof(void *)); -struct hlist_head { - struct hlist_node *first; +struct hlist_node { + struct hlist_node *next __aligned(sizeof(void *)); + struct hlist_node **pprev __aligned(sizeof(void *)); +} __aligned(sizeof(void *)); +#else +struct list_head { + struct list_head *next, *prev; }; struct hlist_node { struct hlist_node *next, **pprev; }; +#endif + +struct hlist_head { + struct hlist_node *first; +}; struct ustat { __kernel_daddr_t f_tfree;
As preparation to using write rare on the nodes of various types of lists, specify that the fields in the basic data structures must be aligned to sizeof(void *) It is meant to ensure that any static allocation will not cross a page boundary, to allow pointers to be updated in one step. Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> CC: Andrew Morton <akpm@linux-foundation.org> CC: Masahiro Yamada <yamada.masahiro@socionext.com> CC: Alexey Dobriyan <adobriyan@gmail.com> CC: Pekka Enberg <penberg@kernel.org> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> CC: Lihao Liang <lianglihao@huawei.com> CC: linux-kernel@vger.kernel.org --- include/linux/types.h | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)