| Message ID | 1461758075-21815-1-git-send-email-mhocko@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Apr 27, 2016, at 5:54 AM, Michal Hocko <mhocko@kernel.org> wrote: > > From: Michal Hocko <mhocko@suse.com> > > xfs has defined PF_FSTRANS to declare a scope GFP_NOFS semantic quite > some time ago. We would like to make this concept more generic and use > it for other filesystems as well. Let's start by giving the flag a > more genric name PF_MEMALLOC_NOFS which is in line with an exiting > PF_MEMALLOC_NOIO already used for the same purpose for GFP_NOIO > contexts. Replace all PF_FSTRANS usage from the xfs code in the first > step before we introduce a full API for it as xfs uses the flag directly > anyway. > > This patch doesn't introduce any functional change. > > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > Hi, > as suggested by Dave, I have split up [1] into two parts. The first one > addes a new PF flag which is just an alias to the existing PF_FSTRANS > and does all the renaming and the second one to introduce the generic > API which only changes the bare minimum in the xfs proper. > > fs/xfs/kmem.c | 4 ++-- > fs/xfs/kmem.h | 2 +- > fs/xfs/libxfs/xfs_btree.c | 2 +- > fs/xfs/xfs_aops.c | 6 +++--- > fs/xfs/xfs_trans.c | 12 ++++++------ > include/linux/sched.h | 2 ++ > 6 files changed, 15 insertions(+), 13 deletions(-) > > diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c > index 686ba6fb20dd..73f6ab59c664 100644 > --- a/fs/xfs/kmem.c > +++ b/fs/xfs/kmem.c > @@ -80,13 +80,13 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags) > * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering > * the filesystem here and potentially deadlocking. > */ > - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) > + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) > noio_flag = memalloc_noio_save(); > > lflags = kmem_flags_convert(flags); > ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); > > - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) > + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) > memalloc_noio_restore(noio_flag); Not really the fault of this patch, but it brings this nasty bit of code into the light. Is all of this machinery still needed given that __vmalloc() can accept GFP flags? If yes, wouldn't it be better to fix __vmalloc() to honor the GFP flags instead of working around it in the filesystem code? Cheers, Andreas > return ptr; > diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h > index d1c66e465ca5..0d83f332e5c2 100644 > --- a/fs/xfs/kmem.h > +++ b/fs/xfs/kmem.h > @@ -50,7 +50,7 @@ kmem_flags_convert(xfs_km_flags_t flags) > lflags = GFP_ATOMIC | __GFP_NOWARN; > } else { > lflags = GFP_KERNEL | __GFP_NOWARN; > - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) > + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) > lflags &= ~__GFP_FS; > } > > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c > index a0eb18ce3ad3..326566f4a131 100644 > --- a/fs/xfs/libxfs/xfs_btree.c > +++ b/fs/xfs/libxfs/xfs_btree.c > @@ -2540,7 +2540,7 @@ xfs_btree_split_worker( > struct xfs_btree_split_args *args = container_of(work, > struct xfs_btree_split_args, work); > unsigned long pflags; > - unsigned long new_pflags = PF_FSTRANS; > + unsigned long new_pflags = PF_MEMALLOC_NOFS; > > /* > * we are in a transaction context here, but may also be doing work > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index d12dfcfd0cc8..6d816ff0b763 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -124,7 +124,7 @@ xfs_setfilesize_trans_alloc( > * We hand off the transaction to the completion thread now, so > * clear the flag here. > */ > - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > return 0; > } > > @@ -169,7 +169,7 @@ xfs_setfilesize_ioend( > * thus we need to mark ourselves as being in a transaction manually. > * Similarly for freeze protection. > */ > - current_set_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS); > > /* we abort the update if there was an IO error */ > @@ -979,7 +979,7 @@ xfs_vm_writepage( > * Given that we do not allow direct reclaim to call us, we should > * never be called while in a filesystem transaction. > */ > - if (WARN_ON_ONCE(current->flags & PF_FSTRANS)) > + if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS)) > goto redirty; > > /* Is this page beyond the end of the file? */ > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > index 748b16aff45a..1d247366c733 100644 > --- a/fs/xfs/xfs_trans.c > +++ b/fs/xfs/xfs_trans.c > @@ -176,7 +176,7 @@ xfs_trans_reserve( > bool rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0; > > /* Mark this thread as being in a transaction */ > - current_set_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > > /* > * Attempt to reserve the needed disk blocks by decrementing > @@ -186,7 +186,7 @@ xfs_trans_reserve( > if (blocks > 0) { > error = xfs_mod_fdblocks(tp->t_mountp, -((int64_t)blocks), rsvd); > if (error != 0) { > - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > return -ENOSPC; > } > tp->t_blk_res += blocks; > @@ -263,7 +263,7 @@ xfs_trans_reserve( > tp->t_blk_res = 0; > } > > - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > > return error; > } > @@ -921,7 +921,7 @@ __xfs_trans_commit( > > xfs_log_commit_cil(mp, tp, &commit_lsn, regrant); > > - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > xfs_trans_free(tp); > > /* > @@ -951,7 +951,7 @@ __xfs_trans_commit( > if (commit_lsn == -1 && !error) > error = -EIO; > } > - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > xfs_trans_free_items(tp, NULLCOMMITLSN, !!error); > xfs_trans_free(tp); > > @@ -1005,7 +1005,7 @@ xfs_trans_cancel( > xfs_log_done(mp, tp->t_ticket, NULL, false); > > /* mark this thread as no longer being in a transaction */ > - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); > + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); > > xfs_trans_free_items(tp, NULLCOMMITLSN, dirty); > xfs_trans_free(tp); > diff --git a/include/linux/sched.h b/include/linux/sched.h > index acfc32b30704..820db8f98bfc 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -2115,6 +2115,8 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, > #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */ > #define PF_SUSPEND_TASK 0x80000000 /* this thread called freeze_processes and should not be frozen */ > > +#define PF_MEMALLOC_NOFS PF_FSTRANS /* Transition to a more generic GFP_NOFS scope semantic */ > + > /* > * Only the _current_ task can read/write to tsk->flags, but other > * tasks can access tsk->flags in readonly mode for example > -- > 2.8.0.rc3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas
On Wed 27-04-16 11:41:51, Andreas Dilger wrote: > On Apr 27, 2016, at 5:54 AM, Michal Hocko <mhocko@kernel.org> wrote: [...] > > --- a/fs/xfs/kmem.c > > +++ b/fs/xfs/kmem.c > > @@ -80,13 +80,13 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags) > > * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering > > * the filesystem here and potentially deadlocking. > > */ > > - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) > > + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) > > noio_flag = memalloc_noio_save(); > > > > lflags = kmem_flags_convert(flags); > > ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); > > > > - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) > > + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) > > memalloc_noio_restore(noio_flag); > > Not really the fault of this patch, but it brings this nasty bit of code into > the light. Is all of this machinery still needed given that __vmalloc() can > accept GFP flags? If yes, wouldn't it be better to fix __vmalloc() to honor > the GFP flags instead of working around it in the filesystem code? This is not that easy. __vmalloc can accept gfp flags but it doesn't honor __GFP_IO 100%. IIRC some paths like page table allocations are hardcoded GFP_KERNEL. Besides that I would like to have GFP_NOIO used via memalloc_noio_{save,restore} API as well for the similar reasons as GFP_NOFS - it is just easier to explain scope than particular code paths which might be shared.
diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c index 686ba6fb20dd..73f6ab59c664 100644 --- a/fs/xfs/kmem.c +++ b/fs/xfs/kmem.c @@ -80,13 +80,13 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags) * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering * the filesystem here and potentially deadlocking. */ - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) noio_flag = memalloc_noio_save(); lflags = kmem_flags_convert(flags); ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) memalloc_noio_restore(noio_flag); return ptr; diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h index d1c66e465ca5..0d83f332e5c2 100644 --- a/fs/xfs/kmem.h +++ b/fs/xfs/kmem.h @@ -50,7 +50,7 @@ kmem_flags_convert(xfs_km_flags_t flags) lflags = GFP_ATOMIC | __GFP_NOWARN; } else { lflags = GFP_KERNEL | __GFP_NOWARN; - if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) + if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) lflags &= ~__GFP_FS; } diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index a0eb18ce3ad3..326566f4a131 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -2540,7 +2540,7 @@ xfs_btree_split_worker( struct xfs_btree_split_args *args = container_of(work, struct xfs_btree_split_args, work); unsigned long pflags; - unsigned long new_pflags = PF_FSTRANS; + unsigned long new_pflags = PF_MEMALLOC_NOFS; /* * we are in a transaction context here, but may also be doing work diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index d12dfcfd0cc8..6d816ff0b763 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -124,7 +124,7 @@ xfs_setfilesize_trans_alloc( * We hand off the transaction to the completion thread now, so * clear the flag here. */ - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); return 0; } @@ -169,7 +169,7 @@ xfs_setfilesize_ioend( * thus we need to mark ourselves as being in a transaction manually. * Similarly for freeze protection. */ - current_set_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS); /* we abort the update if there was an IO error */ @@ -979,7 +979,7 @@ xfs_vm_writepage( * Given that we do not allow direct reclaim to call us, we should * never be called while in a filesystem transaction. */ - if (WARN_ON_ONCE(current->flags & PF_FSTRANS)) + if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS)) goto redirty; /* Is this page beyond the end of the file? */ diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index 748b16aff45a..1d247366c733 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -176,7 +176,7 @@ xfs_trans_reserve( bool rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0; /* Mark this thread as being in a transaction */ - current_set_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); /* * Attempt to reserve the needed disk blocks by decrementing @@ -186,7 +186,7 @@ xfs_trans_reserve( if (blocks > 0) { error = xfs_mod_fdblocks(tp->t_mountp, -((int64_t)blocks), rsvd); if (error != 0) { - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); return -ENOSPC; } tp->t_blk_res += blocks; @@ -263,7 +263,7 @@ xfs_trans_reserve( tp->t_blk_res = 0; } - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); return error; } @@ -921,7 +921,7 @@ __xfs_trans_commit( xfs_log_commit_cil(mp, tp, &commit_lsn, regrant); - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); xfs_trans_free(tp); /* @@ -951,7 +951,7 @@ __xfs_trans_commit( if (commit_lsn == -1 && !error) error = -EIO; } - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); xfs_trans_free_items(tp, NULLCOMMITLSN, !!error); xfs_trans_free(tp); @@ -1005,7 +1005,7 @@ xfs_trans_cancel( xfs_log_done(mp, tp->t_ticket, NULL, false); /* mark this thread as no longer being in a transaction */ - current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); + current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS); xfs_trans_free_items(tp, NULLCOMMITLSN, dirty); xfs_trans_free(tp); diff --git a/include/linux/sched.h b/include/linux/sched.h index acfc32b30704..820db8f98bfc 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2115,6 +2115,8 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */ #define PF_SUSPEND_TASK 0x80000000 /* this thread called freeze_processes and should not be frozen */ +#define PF_MEMALLOC_NOFS PF_FSTRANS /* Transition to a more generic GFP_NOFS scope semantic */ + /* * Only the _current_ task can read/write to tsk->flags, but other * tasks can access tsk->flags in readonly mode for example