Message-ID: <CAMuHMdUQp3wX1V6cgUT7SG43_G=89z2+nPoeeL8WyoqYw5WcnA@mail.gmail.com>
Date:	Fri, 28 Dec 2012 20:59:01 +0100
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Dan Magenheimer <dan.magenheimer@...cle.com>
Cc:	devel@...uxdriverproject.org, linux-kernel@...r.kernel.org,
	gregkh@...uxfoundation.org, linux-mm@...ck.org, ngupta@...are.org,
	konrad.wilk@...cle.com, sjenning@...ux.vnet.ibm.com,
	minchan@...nel.org
Subject: Re: [PATCH 2/3] staging: ramster: move to new zcache2 codebase

On Wed, Sep 5, 2012 at 10:45 PM, Dan Magenheimer
<dan.magenheimer@...cle.com> wrote:
> + * These are all informative and exposed through debugfs... except for
> + * the arrays... anyone know how to do that?  To avoid confusion for

debugfs_create_u32_array()?

> + * debugfs viewers, some of these should also be atomic_long_t, but
> + * I don't know how to expose atomics via debugfs either...
> + */
> +static unsigned long zbud_eph_pageframes;
> +static unsigned long zbud_pers_pageframes;
> +static unsigned long zbud_eph_zpages;
> +static unsigned long zbud_pers_zpages;
> +static u64 zbud_eph_zbytes;
> +static u64 zbud_pers_zbytes;
> +static unsigned long zbud_eph_evicted_pageframes;
> +static unsigned long zbud_pers_evicted_pageframes;
> +static unsigned long zbud_eph_cumul_zpages;
> +static unsigned long zbud_pers_cumul_zpages;
> +static u64 zbud_eph_cumul_zbytes;
> +static u64 zbud_pers_cumul_zbytes;
> +static unsigned long zbud_eph_cumul_chunk_counts[NCHUNKS];
> +static unsigned long zbud_pers_cumul_chunk_counts[NCHUNKS];
> +static unsigned long zbud_eph_buddied_count;
> +static unsigned long zbud_pers_buddied_count;
> +static unsigned long zbud_eph_unbuddied_count;
> +static unsigned long zbud_pers_unbuddied_count;
> +static unsigned long zbud_eph_zombie_count;
> +static unsigned long zbud_pers_zombie_count;
> +static atomic_t zbud_eph_zombie_atomic;
> +static atomic_t zbud_pers_zombie_atomic;
> +
> +#ifdef CONFIG_DEBUG_FS
> +#include <linux/debugfs.h>
> +#define        zdfs    debugfs_create_size_t
> +#define        zdfs64  debugfs_create_u64
> +static int zbud_debugfs_init(void)
> +{
> +       struct dentry *root = debugfs_create_dir("zbud", NULL);
> +       if (root == NULL)
> +               return -ENXIO;
> +
> +       /*
> +        * would be nice to dump the sizes of the unbuddied
> +        * arrays, like was done with sysfs, but it doesn't
> +        * look like debugfs is flexible enough to do that
> +        */
> +       zdfs64("eph_zbytes", S_IRUGO, root, &zbud_eph_zbytes);
> +       zdfs64("eph_cumul_zbytes", S_IRUGO, root, &zbud_eph_cumul_zbytes);
> +       zdfs64("pers_zbytes", S_IRUGO, root, &zbud_pers_zbytes);
> +       zdfs64("pers_cumul_zbytes", S_IRUGO, root, &zbud_pers_cumul_zbytes);
> +       zdfs("eph_cumul_zpages", S_IRUGO, root, &zbud_eph_cumul_zpages);
> +       zdfs("eph_evicted_pageframes", S_IRUGO, root,
> +                               &zbud_eph_evicted_pageframes);
> +       zdfs("eph_zpages", S_IRUGO, root, &zbud_eph_zpages);
> +       zdfs("eph_pageframes", S_IRUGO, root, &zbud_eph_pageframes);
> +       zdfs("eph_buddied_count", S_IRUGO, root, &zbud_eph_buddied_count);
> +       zdfs("eph_unbuddied_count", S_IRUGO, root, &zbud_eph_unbuddied_count);
> +       zdfs("pers_cumul_zpages", S_IRUGO, root, &zbud_pers_cumul_zpages);
> +       zdfs("pers_evicted_pageframes", S_IRUGO, root,
> +                               &zbud_pers_evicted_pageframes);
> +       zdfs("pers_zpages", S_IRUGO, root, &zbud_pers_zpages);
> +       zdfs("pers_pageframes", S_IRUGO, root, &zbud_pers_pageframes);
> +       zdfs("pers_buddied_count", S_IRUGO, root, &zbud_pers_buddied_count);
> +       zdfs("pers_unbuddied_count", S_IRUGO, root, &zbud_pers_unbuddied_count);
> +       zdfs("pers_zombie_count", S_IRUGO, root, &zbud_pers_zombie_count);
> +       return 0;
> +}
> +#undef zdfs
> +#undef zdfs64
> +#endif

On m68k (see e.g.
http://kisskb.ellerman.id.au/kisskb/buildresult/7864856/), I'm getting
lots of warnings for this:

drivers/staging/ramster/zbud.c: In function ‘zbud_debugfs_init’:
drivers/staging/ramster/zbud.c:323: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:325: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:326: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:327: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:328: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:329: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:330: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:332: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:333: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:334: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:335: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:336: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zbud.c:337: warning: passing argument 4 of
‘debugfs_create_size_t’ from incompatible pointer type

as you're using debugfs_create_size_t() to refer to "unsigned long"
instead of "size_t".

Some of the variables you can change from "unsigned long" to "size_t",
as you just increment
or decrement them.
For others, that's not a good idea, as you assign them the return value of
atomic_inc_return()/atomic_dec_return(), which is "int", i.e. always 32-bit,
while "size_t" is 64-bit on 64-bit platforms.

zcache-main.c suffers from similar problems:

drivers/staging/ramster/zcache-main.c: In function ‘zcache_debugfs_init’:
drivers/staging/ramster/zcache-main.c:195: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:196: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:197: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:198: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:199: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:200: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:201: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:202: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:203: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:204: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:206: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:207: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:208: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:209: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:210: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:211: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:212: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:213: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:214: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:215: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:217: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:218: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:219: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:220: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:221: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:222: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:223: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:224: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:225: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:227: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:229: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:231: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:233: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:235: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type
drivers/staging/ramster/zcache-main.c:237: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type

But there is more work to do, as zcache_dump() formats many of them as "%lu",
which should be "%zu" if you convert the counters to size_t.
Note that you do not have to cast a "u64" to "unsigned long long" to format it
using "%llu", so please remove the casts.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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