* Re: [PATCH] mm: introduce kv[mz]alloc helpers
2017-01-05 10:40 ` [PATCH] mm: introduce kv[mz]alloc helpers Tetsuo Handa
@ 2017-01-05 10:59 ` Michal Hocko
2017-01-06 14:54 ` Kent Overstreet
1 sibling, 0 replies; 3+ messages in thread
From: Michal Hocko @ 2017-01-05 10:59 UTC (permalink / raw)
To: Tetsuo Handa; +Cc: Andrew Morton, linux-mm, linux-bcache, kent.overstreet
On Thu 05-01-17 19:40:10, Tetsuo Handa wrote:
> On 2017/01/04 23:20, Michal Hocko wrote:
> > OK, so I've checked the open coded implementations and converted most of
> > them. There are few which are either confused and need some special
> > handling or need double checking.
> >
> > diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
> > index cf2cbc211d83..9dc0f0ff0321 100644
> > --- a/drivers/md/bcache/util.h
> > +++ b/drivers/md/bcache/util.h
> > @@ -44,10 +44,7 @@ struct closure;
> > (heap)->size = (_size); \
> > _bytes = (heap)->size * sizeof(*(heap)->data); \
> > (heap)->data = NULL; \
> > - if (_bytes < KMALLOC_MAX_SIZE) \
> > - (heap)->data = kmalloc(_bytes, (gfp)); \
> > - if ((!(heap)->data) && ((gfp) & GFP_KERNEL)) \
> > - (heap)->data = vmalloc(_bytes); \
> > + (heap)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \
> > (heap)->data; \
> > })
> >
> > @@ -138,10 +135,7 @@ do { \
> > (fifo)->front = (fifo)->back = 0; \
> > (fifo)->data = NULL; \
> > \
> > - if (_bytes < KMALLOC_MAX_SIZE) \
> > - (fifo)->data = kmalloc(_bytes, (gfp)); \
> > - if ((!(fifo)->data) && ((gfp) & GFP_KERNEL)) \
> > - (fifo)->data = vmalloc(_bytes); \
> > + (fifo)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \
> > (fifo)->data; \
> > })
>
> These macros are doing strange checks.
> ((gfp) & GFP_KERNEL) means any bit in GFP_KERNEL is set.
> ((gfp) & GFP_KERNEL) == GFP_KERNEL might make sense. Actually,
> all callers seems to be passing GFP_KERNEL to these macros.
Yes the code is confused. I've seen worse when going through the drivers
code...
> Kent, how do you want to correct this? You want to apply
> a patch that removes gfp argument before applying this patch?
> Or, you want Michal to directly overwrite by this patch?
I would just get rid of it here as init_heap has just one caller with
GFP_KERNEL and __init_fifo has GFP_KERNEL users as well. But if it is
preferable to clean up this first then I can do that.
> Michal, "(fifo)->data = NULL;" line will become redundant
> and "(gfp) & GFP_KERNEL" will become "GFP_KERNEL".
true. will remove it.
--
Michal Hocko
SUSE Labs
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] mm: introduce kv[mz]alloc helpers
2017-01-05 10:40 ` [PATCH] mm: introduce kv[mz]alloc helpers Tetsuo Handa
2017-01-05 10:59 ` Michal Hocko
@ 2017-01-06 14:54 ` Kent Overstreet
1 sibling, 0 replies; 3+ messages in thread
From: Kent Overstreet @ 2017-01-06 14:54 UTC (permalink / raw)
To: Tetsuo Handa; +Cc: Michal Hocko, Andrew Morton, linux-mm, linux-bcache
On Thu, Jan 05, 2017 at 07:40:10PM +0900, Tetsuo Handa wrote:
> On 2017/01/04 23:20, Michal Hocko wrote:
> > OK, so I've checked the open coded implementations and converted most of
> > them. There are few which are either confused and need some special
> > handling or need double checking.
> >
> > diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
> > index cf2cbc211d83..9dc0f0ff0321 100644
> > --- a/drivers/md/bcache/util.h
> > +++ b/drivers/md/bcache/util.h
> > @@ -44,10 +44,7 @@ struct closure;
> > (heap)->size = (_size); \
> > _bytes = (heap)->size * sizeof(*(heap)->data); \
> > (heap)->data = NULL; \
> > - if (_bytes < KMALLOC_MAX_SIZE) \
> > - (heap)->data = kmalloc(_bytes, (gfp)); \
> > - if ((!(heap)->data) && ((gfp) & GFP_KERNEL)) \
> > - (heap)->data = vmalloc(_bytes); \
> > + (heap)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \
> > (heap)->data; \
> > })
> >
> > @@ -138,10 +135,7 @@ do { \
> > (fifo)->front = (fifo)->back = 0; \
> > (fifo)->data = NULL; \
> > \
> > - if (_bytes < KMALLOC_MAX_SIZE) \
> > - (fifo)->data = kmalloc(_bytes, (gfp)); \
> > - if ((!(fifo)->data) && ((gfp) & GFP_KERNEL)) \
> > - (fifo)->data = vmalloc(_bytes); \
> > + (fifo)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \
> > (fifo)->data; \
> > })
>
> These macros are doing strange checks.
> ((gfp) & GFP_KERNEL) means any bit in GFP_KERNEL is set.
> ((gfp) & GFP_KERNEL) == GFP_KERNEL might make sense. Actually,
> all callers seems to be passing GFP_KERNEL to these macros.
>
> Kent, how do you want to correct this? You want to apply
> a patch that removes gfp argument before applying this patch?
> Or, you want Michal to directly overwrite by this patch?
>
> Michal, "(fifo)->data = NULL;" line will become redundant
> and "(gfp) & GFP_KERNEL" will become "GFP_KERNEL".
Please just go ahead and replace all that crap with a single call to kvmalloc().
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^ permalink raw reply [flat|nested] 3+ messages in thread