Messages in this thread | | | Date | Mon, 2 Feb 2015 16:37:08 +1100 | From | Dave Chinner <> | Subject | Re: [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations. |
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On Sun, Feb 01, 2015 at 10:59:54PM -0500, green@linuxhacker.ru wrote: > From: Oleg Drokin <green@linuxhacker.ru> > > leaf_dealloc uses vzalloc as a fallback to kzalloc(GFP_NOFS), so > it clearly does not want any shrinker activity within the fs itself. > convert vzalloc into __vmalloc(GFP_NOFS|__GFP_ZERO) to better achieve > this goal. > > Signed-off-by: Oleg Drokin <green@linuxhacker.ru> > --- > fs/gfs2/dir.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c > index c5a34f0..6371192 100644 > --- a/fs/gfs2/dir.c > +++ b/fs/gfs2/dir.c > @@ -1896,7 +1896,8 @@ static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len, > > ht = kzalloc(size, GFP_NOFS | __GFP_NOWARN); > if (ht == NULL) > - ht = vzalloc(size); > + ht = __vmalloc(size, GFP_NOFS | __GFP_NOWARN | __GFP_ZERO, > + PAGE_KERNEL);
That, in the end, won't help as vmalloc still uses GFP_KERNEL allocations deep down in the PTE allocation code. See the hacks in the DM and XFS code to work around this. i.e. go look for callers of memalloc_noio_save(). It's ugly and grotesque, but we've got no other way to limit reclaim context because the MM devs won't pass the vmalloc gfp context down the stack to the PTE allocations....
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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