From: Andrew Morton <akpm@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Vitaly Wool <vitalywool@gmail.com>, Linux-MM <linux-mm@kvack.org>,
linux-kernel@vger.kernel.org, Dan Streetman <ddstreet@ieee.org>
Subject: Re: [PATCH v3] z3fold: use per-page read/write lock
Date: Wed, 9 Nov 2016 16:32:41 -0800 [thread overview]
Message-ID: <20161109163241.c73742590270710040fdd25a@linux-foundation.org> (raw)
In-Reply-To: <20161109230117.GO26852@two.firstfloor.org>
On Wed, 9 Nov 2016 15:01:17 -0800 Andi Kleen <andi@firstfloor.org> wrote:
> On Wed, Nov 09, 2016 at 02:33:04PM -0800, Andrew Morton wrote:
> > On Wed, 9 Nov 2016 11:55:31 +0100 Vitaly Wool <vitalywool@gmail.com> wrote:
> >
> > > Subject: [PATCH v3] z3fold: use per-page read/write lock
> >
> > I've rewritten the title to "mm/z3fold.c: use per-page spinlock"
> >
> > (I prefer to have "mm" in the title to easily identify it as an MM
> > patch, and using "mm: z3fold: ..." seems odd when the actual pathname
> > conveys the same info.)
>
> Still think it needs to be raw_spinlock_t, otherwise the build bug on
> on the header size will break again.
>
> Better would be to fix that build bug though
Yeah, that triggers for me immediately. We could suppress it with
something silly like
--- a/mm/z3fold.c~z3fold-use-per-page-read-write-lock-fix
+++ a/mm/z3fold.c
@@ -872,7 +872,7 @@ MODULE_ALIAS("zpool-z3fold");
static int __init init_z3fold(void)
{
/* Make sure the z3fold header will fit in one chunk */
- BUILD_BUG_ON(sizeof(struct z3fold_header) > ZHDR_SIZE_ALIGNED);
+ BUILD_BUG_ON(sizeof(struct z3fold_header) - sizeof(spinlock_t) > ZHDR_SIZE_ALIGNED);
zpool_register_driver(&z3fold_zpool_driver);
return 0;
but that doesn't fix anything - the header is just too large with
lockdep enabled.
I'll drop the patch for now.
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prev parent reply other threads:[~2016-11-10 0:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-09 10:55 [PATCH v3] z3fold: use per-page read/write lock Vitaly Wool
2016-11-09 22:33 ` Andrew Morton
2016-11-09 23:01 ` Andi Kleen
2016-11-09 23:22 ` Thomas Gleixner
2016-11-10 0:32 ` Andrew Morton [this message]
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