| Message ID | 1488995215-7647-4-git-send-email-ross.lagerwall@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/03/17 17:46, Ross Lagerwall wrote: > Instead of using a locking order based on line numbers which interacts > poorly with trying to create a live patch, statically define the locking > order. > > Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> > Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com> Acked-by: George Dunlap <george.dunlap@citrix.com> > --- > > Changes in v2: > * Rearranged defines. > * Make lock orders fit in a sign-extended 8-bit immediate. > > xen/arch/x86/mm/mm-locks.h | 28 +++++++++++++++++++--------- > 1 file changed, 19 insertions(+), 9 deletions(-) > > diff --git a/xen/arch/x86/mm/mm-locks.h b/xen/arch/x86/mm/mm-locks.h > index 74fdfc1..e5fceb2 100644 > --- a/xen/arch/x86/mm/mm-locks.h > +++ b/xen/arch/x86/mm/mm-locks.h > @@ -46,8 +46,10 @@ static inline int mm_locked_by_me(mm_lock_t *l) > return (l->lock.recurse_cpu == current->processor); > } > > -/* If you see this crash, the numbers printed are lines in this file > - * where the offending locks are declared. */ > +/* > + * If you see this crash, the numbers printed are order levels defined > + * in this file. > + */ > #define __check_lock_level(l) \ > do { \ > if ( unlikely(__get_lock_level() > (l)) ) \ > @@ -152,12 +154,12 @@ static inline void mm_read_unlock(mm_rwlock_t *l) > /* This wrapper uses the line number to express the locking order below */ > #define declare_mm_lock(name) \ > static inline void mm_lock_##name(mm_lock_t *l, const char *func, int rec)\ > - { _mm_lock(l, func, __LINE__, rec); } > + { _mm_lock(l, func, MM_LOCK_ORDER_##name, rec); } > #define declare_mm_rwlock(name) \ > static inline void mm_write_lock_##name(mm_rwlock_t *l, const char *func) \ > - { _mm_write_lock(l, func, __LINE__); } \ > + { _mm_write_lock(l, func, MM_LOCK_ORDER_##name); } \ > static inline void mm_read_lock_##name(mm_rwlock_t *l) \ > - { _mm_read_lock(l, __LINE__); } > + { _mm_read_lock(l, MM_LOCK_ORDER_##name); } > /* These capture the name of the calling function */ > #define mm_lock(name, l) mm_lock_##name(l, __func__, 0) > #define mm_lock_recursive(name, l) mm_lock_##name(l, __func__, 1) > @@ -169,10 +171,10 @@ static inline void mm_read_unlock(mm_rwlock_t *l) > * to ordering constraints. */ > #define declare_mm_order_constraint(name) \ > static inline void mm_enforce_order_lock_pre_##name(void) \ > - { _mm_enforce_order_lock_pre(__LINE__); } \ > + { _mm_enforce_order_lock_pre(MM_LOCK_ORDER_##name); } \ > static inline void mm_enforce_order_lock_post_##name( \ > int *unlock_level, unsigned short *recurse_count) \ > - { _mm_enforce_order_lock_post(__LINE__, unlock_level, recurse_count); } \ > + { _mm_enforce_order_lock_post(MM_LOCK_ORDER_##name, unlock_level, recurse_count); } \ > > static inline void mm_unlock(mm_lock_t *l) > { > @@ -201,8 +203,8 @@ static inline void mm_enforce_order_unlock(int unlock_level, > > /************************************************************************ > * * > - * To avoid deadlocks, these locks _MUST_ be taken in the order they're * > - * declared in this file. The locking functions will enforce this. * > + * To avoid deadlocks, these locks _MUST_ be taken in the order listed * > + * below. The locking functions will enforce this. * > * * > ************************************************************************/ > > @@ -214,6 +216,7 @@ static inline void mm_enforce_order_unlock(int unlock_level, > * - setting the "cr3" field of any p2m table to a non-P2M_BASE_EAADR value. > * (i.e. assigning a p2m table to be the shadow of that cr3 */ > > +#define MM_LOCK_ORDER_nestedp2m 8 > declare_mm_lock(nestedp2m) > #define nestedp2m_lock(d) mm_lock(nestedp2m, &(d)->arch.nested_p2m_lock) > #define nestedp2m_unlock(d) mm_unlock(&(d)->arch.nested_p2m_lock) > @@ -240,6 +243,7 @@ declare_mm_lock(nestedp2m) > * the altp2mlist lock in the middle. > */ > > +#define MM_LOCK_ORDER_p2m 16 > declare_mm_rwlock(p2m); > > /* Sharing per page lock > @@ -251,6 +255,7 @@ declare_mm_rwlock(p2m); > * > * The lock is recursive because during share we lock two pages. */ > > +#define MM_LOCK_ORDER_per_page_sharing 24 > declare_mm_order_constraint(per_page_sharing) > #define page_sharing_mm_pre_lock() mm_enforce_order_lock_pre_per_page_sharing() > #define page_sharing_mm_post_lock(l, r) \ > @@ -265,6 +270,7 @@ declare_mm_order_constraint(per_page_sharing) > * in the target domain must be paused. > */ > > +#define MM_LOCK_ORDER_altp2mlist 32 > declare_mm_lock(altp2mlist) > #define altp2m_list_lock(d) mm_lock(altp2mlist, &(d)->arch.altp2m_list_lock) > #define altp2m_list_unlock(d) mm_unlock(&(d)->arch.altp2m_list_lock) > @@ -279,6 +285,7 @@ declare_mm_lock(altp2mlist) > * up a gfn and later mutate it. > */ > > +#define MM_LOCK_ORDER_altp2m 40 > declare_mm_rwlock(altp2m); > #define p2m_lock(p) \ > do { \ > @@ -307,6 +314,7 @@ declare_mm_rwlock(altp2m); > * Protects private PoD data structs: entry and cache > * counts, page lists, sweep parameters. */ > > +#define MM_LOCK_ORDER_pod 48 > declare_mm_lock(pod) > #define pod_lock(p) mm_lock(pod, &(p)->pod.lock) > #define pod_unlock(p) mm_unlock(&(p)->pod.lock) > @@ -319,6 +327,7 @@ declare_mm_lock(pod) > * the ordering which we enforce here. > * The lock is not recursive. */ > > +#define MM_LOCK_ORDER_page_alloc 56 > declare_mm_order_constraint(page_alloc) > #define page_alloc_mm_pre_lock() mm_enforce_order_lock_pre_page_alloc() > #define page_alloc_mm_post_lock(l) mm_enforce_order_lock_post_page_alloc(&(l), NULL) > @@ -339,6 +348,7 @@ declare_mm_order_constraint(page_alloc) > * It also protects the log-dirty bitmap from concurrent accesses (and > * teardowns, etc). */ > > +#define MM_LOCK_ORDER_paging 64 > declare_mm_lock(paging) > #define paging_lock(d) mm_lock(paging, &(d)->arch.paging.lock) > #define paging_lock_recursive(d) \ >
diff --git a/xen/arch/x86/mm/mm-locks.h b/xen/arch/x86/mm/mm-locks.h index 74fdfc1..e5fceb2 100644 --- a/xen/arch/x86/mm/mm-locks.h +++ b/xen/arch/x86/mm/mm-locks.h @@ -46,8 +46,10 @@ static inline int mm_locked_by_me(mm_lock_t *l) return (l->lock.recurse_cpu == current->processor); } -/* If you see this crash, the numbers printed are lines in this file - * where the offending locks are declared. */ +/* + * If you see this crash, the numbers printed are order levels defined + * in this file. + */ #define __check_lock_level(l) \ do { \ if ( unlikely(__get_lock_level() > (l)) ) \ @@ -152,12 +154,12 @@ static inline void mm_read_unlock(mm_rwlock_t *l) /* This wrapper uses the line number to express the locking order below */ #define declare_mm_lock(name) \ static inline void mm_lock_##name(mm_lock_t *l, const char *func, int rec)\ - { _mm_lock(l, func, __LINE__, rec); } + { _mm_lock(l, func, MM_LOCK_ORDER_##name, rec); } #define declare_mm_rwlock(name) \ static inline void mm_write_lock_##name(mm_rwlock_t *l, const char *func) \ - { _mm_write_lock(l, func, __LINE__); } \ + { _mm_write_lock(l, func, MM_LOCK_ORDER_##name); } \ static inline void mm_read_lock_##name(mm_rwlock_t *l) \ - { _mm_read_lock(l, __LINE__); } + { _mm_read_lock(l, MM_LOCK_ORDER_##name); } /* These capture the name of the calling function */ #define mm_lock(name, l) mm_lock_##name(l, __func__, 0) #define mm_lock_recursive(name, l) mm_lock_##name(l, __func__, 1) @@ -169,10 +171,10 @@ static inline void mm_read_unlock(mm_rwlock_t *l) * to ordering constraints. */ #define declare_mm_order_constraint(name) \ static inline void mm_enforce_order_lock_pre_##name(void) \ - { _mm_enforce_order_lock_pre(__LINE__); } \ + { _mm_enforce_order_lock_pre(MM_LOCK_ORDER_##name); } \ static inline void mm_enforce_order_lock_post_##name( \ int *unlock_level, unsigned short *recurse_count) \ - { _mm_enforce_order_lock_post(__LINE__, unlock_level, recurse_count); } \ + { _mm_enforce_order_lock_post(MM_LOCK_ORDER_##name, unlock_level, recurse_count); } \ static inline void mm_unlock(mm_lock_t *l) { @@ -201,8 +203,8 @@ static inline void mm_enforce_order_unlock(int unlock_level, /************************************************************************ * * - * To avoid deadlocks, these locks _MUST_ be taken in the order they're * - * declared in this file. The locking functions will enforce this. * + * To avoid deadlocks, these locks _MUST_ be taken in the order listed * + * below. The locking functions will enforce this. * * * ************************************************************************/ @@ -214,6 +216,7 @@ static inline void mm_enforce_order_unlock(int unlock_level, * - setting the "cr3" field of any p2m table to a non-P2M_BASE_EAADR value. * (i.e. assigning a p2m table to be the shadow of that cr3 */ +#define MM_LOCK_ORDER_nestedp2m 8 declare_mm_lock(nestedp2m) #define nestedp2m_lock(d) mm_lock(nestedp2m, &(d)->arch.nested_p2m_lock) #define nestedp2m_unlock(d) mm_unlock(&(d)->arch.nested_p2m_lock) @@ -240,6 +243,7 @@ declare_mm_lock(nestedp2m) * the altp2mlist lock in the middle. */ +#define MM_LOCK_ORDER_p2m 16 declare_mm_rwlock(p2m); /* Sharing per page lock @@ -251,6 +255,7 @@ declare_mm_rwlock(p2m); * * The lock is recursive because during share we lock two pages. */ +#define MM_LOCK_ORDER_per_page_sharing 24 declare_mm_order_constraint(per_page_sharing) #define page_sharing_mm_pre_lock() mm_enforce_order_lock_pre_per_page_sharing() #define page_sharing_mm_post_lock(l, r) \ @@ -265,6 +270,7 @@ declare_mm_order_constraint(per_page_sharing) * in the target domain must be paused. */ +#define MM_LOCK_ORDER_altp2mlist 32 declare_mm_lock(altp2mlist) #define altp2m_list_lock(d) mm_lock(altp2mlist, &(d)->arch.altp2m_list_lock) #define altp2m_list_unlock(d) mm_unlock(&(d)->arch.altp2m_list_lock) @@ -279,6 +285,7 @@ declare_mm_lock(altp2mlist) * up a gfn and later mutate it. */ +#define MM_LOCK_ORDER_altp2m 40 declare_mm_rwlock(altp2m); #define p2m_lock(p) \ do { \ @@ -307,6 +314,7 @@ declare_mm_rwlock(altp2m); * Protects private PoD data structs: entry and cache * counts, page lists, sweep parameters. */ +#define MM_LOCK_ORDER_pod 48 declare_mm_lock(pod) #define pod_lock(p) mm_lock(pod, &(p)->pod.lock) #define pod_unlock(p) mm_unlock(&(p)->pod.lock) @@ -319,6 +327,7 @@ declare_mm_lock(pod) * the ordering which we enforce here. * The lock is not recursive. */ +#define MM_LOCK_ORDER_page_alloc 56 declare_mm_order_constraint(page_alloc) #define page_alloc_mm_pre_lock() mm_enforce_order_lock_pre_page_alloc() #define page_alloc_mm_post_lock(l) mm_enforce_order_lock_post_page_alloc(&(l), NULL) @@ -339,6 +348,7 @@ declare_mm_order_constraint(page_alloc) * It also protects the log-dirty bitmap from concurrent accesses (and * teardowns, etc). */ +#define MM_LOCK_ORDER_paging 64 declare_mm_lock(paging) #define paging_lock(d) mm_lock(paging, &(d)->arch.paging.lock) #define paging_lock_recursive(d) \