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xfs: use memalloc_nofs_{save,restore} instead of memalloc_noio*

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kmem_zalloc_large and _xfs_buf_map_pages use memalloc_noio_{save,restore}
API to prevent from reclaim recursion into the fs because vmalloc can
invoke unconditional GFP_KERNEL allocations and these functions might be
called from the NOFS contexts.  The memalloc_noio_save will enforce
GFP_NOIO context which is even weaker than GFP_NOFS and that seems to be
unnecessary.  Let's use memalloc_nofs_{save,restore} instead as it
should provide exactly what we need here - implicit GFP_NOFS context.

Link: http://lkml.kernel.org/r/20170306131408.9828-6-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michal Hocko 2017-05-03 14:53:19 -07:00 committed by Linus Torvalds
parent 7dea19f9ee
commit 9ba1fb2c60
2 changed files with 10 additions and 10 deletions
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12
fs/xfs/kmem.c
View File

@ -48,7 +48,7 @@ kmem_alloc(size_t size, xfs_km_flags_t flags)
void *
kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
{
unsigned noio_flag = 0;
unsigned nofs_flag = 0;
void *ptr;
gfp_t lflags;
@ -60,17 +60,17 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
* __vmalloc() will allocate data pages and auxillary structures (e.g.
* pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context
* here. Hence we need to tell memory reclaim that we are in such a
* context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering
* context via PF_MEMALLOC_NOFS to prevent memory reclaim re-entering
* the filesystem here and potentially deadlocking.
*/
if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
noio_flag = memalloc_noio_save();
if (flags & KM_NOFS)
nofs_flag = memalloc_nofs_save();
lflags = kmem_flags_convert(flags);
ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
memalloc_noio_restore(noio_flag);
if (flags & KM_NOFS)
memalloc_nofs_restore(nofs_flag);
return ptr;
}

8
fs/xfs/xfs_buf.c
View File

@ -443,17 +443,17 @@ _xfs_buf_map_pages(
bp->b_addr = NULL;
} else {
int retried = 0;
unsigned noio_flag;
unsigned nofs_flag;
/*
* vm_map_ram() will allocate auxillary structures (e.g.
* pagetables) with GFP_KERNEL, yet we are likely to be under
* GFP_NOFS context here. Hence we need to tell memory reclaim
* that we are in such a context via PF_MEMALLOC_NOIO to prevent
* that we are in such a context via PF_MEMALLOC_NOFS to prevent
* memory reclaim re-entering the filesystem here and
* potentially deadlocking.
*/
noio_flag = memalloc_noio_save();
nofs_flag = memalloc_nofs_save();
do {
bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
-1, PAGE_KERNEL);
@ -461,7 +461,7 @@ _xfs_buf_map_pages(
break;
vm_unmap_aliases();
} while (retried++ <= 1);
memalloc_noio_restore(noio_flag);
memalloc_nofs_restore(nofs_flag);
if (!bp->b_addr)
return -ENOMEM;