On Thu 25-06-20 12:31:20, Matthew Wilcox wrote: > We're short on PF_* flags, so make memalloc_nofs its own bit where we > have plenty of space. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> forgot to add Acked-by: Michal Hocko <mhocko@xxxxxxxx> > --- > fs/iomap/buffered-io.c | 2 +- > include/linux/sched.h | 2 +- > include/linux/sched/mm.h | 13 ++++++------- > 3 files changed, 8 insertions(+), 9 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index bcfc288dba3f..87d66c13bf5c 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -1502,7 +1502,7 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data) > * Given that we do not allow direct reclaim to call us, we should > * never be called in a recursive filesystem reclaim context. > */ > - if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS)) > + if (WARN_ON_ONCE(current->memalloc_nofs)) > goto redirty; > > /* > diff --git a/include/linux/sched.h b/include/linux/sched.h > index cf18a3d2bc4c..eaf36ae1fde2 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -802,6 +802,7 @@ struct task_struct { > unsigned in_memstall:1; > #endif > unsigned memalloc_noio:1; > + unsigned memalloc_nofs:1; > > unsigned long atomic_flags; /* Flags requiring atomic access. */ > > @@ -1505,7 +1506,6 @@ extern struct pid *cad_pid; > #define PF_NOFREEZE 0x00008000 /* This thread should not be frozen */ > #define PF_FROZEN 0x00010000 /* Frozen for system suspend */ > #define PF_KSWAPD 0x00020000 /* I am kswapd */ > -#define PF_MEMALLOC_NOFS 0x00040000 /* All allocation requests will inherit GFP_NOFS */ > #define PF_LOCAL_THROTTLE 0x00100000 /* Throttle writes only against the bdi I write to, > * I am cleaning dirty pages from some other bdi. */ > #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h > index b0089eadc367..08bc9d0606a8 100644 > --- a/include/linux/sched/mm.h > +++ b/include/linux/sched/mm.h > @@ -175,20 +175,19 @@ static inline bool in_vfork(struct task_struct *tsk) > > /* > * Applies per-task gfp context to the given allocation flags. > - * PF_MEMALLOC_NOFS implies GFP_NOFS > * PF_MEMALLOC_NOCMA implies no allocation from CMA region. > */ > static inline gfp_t current_gfp_context(gfp_t flags) > { > - if (unlikely(current->flags & (PF_MEMALLOC_NOFS | PF_MEMALLOC_NOCMA) || > - current->memalloc_noio)) { > + if (unlikely((current->flags & PF_MEMALLOC_NOCMA) || > + current->memalloc_noio || current->memalloc_nofs)) { > /* > * NOIO implies both NOIO and NOFS and it is a weaker context > * so always make sure it makes precedence > */ > if (current->memalloc_noio) > flags &= ~(__GFP_IO | __GFP_FS); > - else if (current->flags & PF_MEMALLOC_NOFS) > + else if (current->memalloc_nofs) > flags &= ~__GFP_FS; > #ifdef CONFIG_CMA > if (current->flags & PF_MEMALLOC_NOCMA) > @@ -254,8 +253,8 @@ static inline void memalloc_noio_restore(unsigned int flags) > */ > static inline unsigned int memalloc_nofs_save(void) > { > - unsigned int flags = current->flags & PF_MEMALLOC_NOFS; > - current->flags |= PF_MEMALLOC_NOFS; > + unsigned int flags = current->memalloc_nofs; > + current->memalloc_nofs = 1; > return flags; > } > > @@ -269,7 +268,7 @@ static inline unsigned int memalloc_nofs_save(void) > */ > static inline void memalloc_nofs_restore(unsigned int flags) > { > - current->flags = (current->flags & ~PF_MEMALLOC_NOFS) | flags; > + current->memalloc_nofs = flags ? 1 : 0; > } > > static inline unsigned int memalloc_noreclaim_save(void) > -- > 2.27.0 -- Michal Hocko SUSE Labs