From: Greg KH <gregkh@linuxfoundation.org>
To: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: leon@kernel.org, vbabka@suse.cz, adobriyan@gmail.com,
akpm@linux-foundation.org, labbott@redhat.com,
sumit.semwal@linaro.org, minchan@kernel.org, ngupta@vflare.org,
sergey.senozhatsky.work@gmail.com, kasong@redhat.com,
bhe@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
jaewon31.kim@gmail.com, linux-api@vger.kernel.org,
kexec@lists.infradead.org
Subject: Re: [RFC PATCH v2 1/3] meminfo_extra: introduce meminfo extra
Date: Mon, 23 Mar 2020 10:53:44 +0100 [thread overview]
Message-ID: <20200323095344.GB425358@kroah.com> (raw)
In-Reply-To: <20200323080503.6224-2-jaewon31.kim@samsung.com>
On Mon, Mar 23, 2020 at 05:05:01PM +0900, Jaewon Kim wrote:
> Provide APIs to drivers so that they can show its memory usage on
> /proc/meminfo_extra.
>
> int register_meminfo_extra(atomic_long_t *val, int shift,
> const char *name);
> int unregister_meminfo_extra(atomic_long_t *val);
Nit, isn't it nicer to have the subsystem name first:
meminfo_extra_register()
meminfo_extra_unregister()
?
>
> Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
> ---
> v2: move to /proc/meminfo_extra as a new file, meminfo_extra.c
> use rcu to reduce lock overhead
> v1: print info at /proc/meminfo
> ---
> fs/proc/Makefile | 1 +
> fs/proc/meminfo_extra.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mm.h | 4 ++
> mm/page_alloc.c | 1 +
> 4 files changed, 129 insertions(+)
> create mode 100644 fs/proc/meminfo_extra.c
>
> diff --git a/fs/proc/Makefile b/fs/proc/Makefile
> index bd08616ed8ba..83d2f55591c6 100644
> --- a/fs/proc/Makefile
> +++ b/fs/proc/Makefile
> @@ -19,6 +19,7 @@ proc-y += devices.o
> proc-y += interrupts.o
> proc-y += loadavg.o
> proc-y += meminfo.o
> +proc-y += meminfo_extra.o
> proc-y += stat.o
> proc-y += uptime.o
> proc-y += util.o
> diff --git a/fs/proc/meminfo_extra.c b/fs/proc/meminfo_extra.c
> new file mode 100644
> index 000000000000..bd3f0d2b7fb7
> --- /dev/null
> +++ b/fs/proc/meminfo_extra.c
> @@ -0,0 +1,123 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/mm.h>
> +#include <linux/proc_fs.h>
> +#include <linux/seq_file.h>
> +#include <linux/slab.h>
> +
> +static void show_val_kb(struct seq_file *m, const char *s, unsigned long num)
> +{
> + seq_put_decimal_ull_width(m, s, num << (PAGE_SHIFT - 10), 8);
> + seq_write(m, " kB\n", 4);
> +}
> +
> +static LIST_HEAD(meminfo_head);
> +static DEFINE_SPINLOCK(meminfo_lock);
> +
> +#define NAME_SIZE 15
> +#define NAME_BUF_SIZE (NAME_SIZE + 2) /* ':' and '\0' */
> +
> +struct meminfo_extra {
> + struct list_head list;
> + atomic_long_t *val;
> + int shift_for_page;
> + char name[NAME_BUF_SIZE];
> + char name_pad[NAME_BUF_SIZE];
> +};
> +
> +int register_meminfo_extra(atomic_long_t *val, int shift, const char *name)
> +{
> + struct meminfo_extra *meminfo, *memtemp;
> + int len;
> + int error = 0;
> +
> + meminfo = kzalloc(sizeof(*meminfo), GFP_KERNEL);
> + if (!meminfo) {
> + error = -ENOMEM;
> + goto out;
> + }
> +
> + meminfo->val = val;
> + meminfo->shift_for_page = shift;
> + strncpy(meminfo->name, name, NAME_SIZE);
> + len = strlen(meminfo->name);
> + meminfo->name[len] = ':';
> + strncpy(meminfo->name_pad, meminfo->name, NAME_BUF_SIZE);
> + while (++len < NAME_BUF_SIZE - 1)
> + meminfo->name_pad[len] = ' ';
> +
> + spin_lock(&meminfo_lock);
> + list_for_each_entry_rcu(memtemp, &meminfo_head, list) {
> + if (memtemp->val == val) {
> + error = -EINVAL;
> + break;
> + }
> + }
> + if (!error)
> + list_add_tail_rcu(&meminfo->list, &meminfo_head);
> + spin_unlock(&meminfo_lock);
If you have a lock, why are you needing rcu?
> + if (error)
> + kfree(meminfo);
> +out:
> +
> + return error;
> +}
> +EXPORT_SYMBOL(register_meminfo_extra);
EXPORT_SYMBOL_GPL()? I have to ask :)
thanks,
greg k-h
next prev parent reply other threads:[~2020-03-23 9:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200323080507epcas1p44cdb9ecb70a7a7395b3acddeda3cfd89@epcas1p4.samsung.com>
2020-03-23 8:05 ` [RFC PATCH v2 0/3] meminfo_extra: introduce meminfo extra Jaewon Kim
[not found] ` <CGME20200323080508epcas1p387c9c19b480da53be40fe5d51e76a477@epcas1p3.samsung.com>
2020-03-23 8:05 ` [RFC PATCH v2 1/3] " Jaewon Kim
2020-03-23 9:53 ` Greg KH [this message]
2020-03-24 9:11 ` Jaewon Kim
2020-03-24 10:11 ` Greg KH
2020-03-24 11:37 ` Jaewon Kim
2020-03-24 11:46 ` Greg KH
2020-03-24 12:53 ` Jaewon Kim
2020-03-24 13:19 ` Greg KH
2020-03-26 8:21 ` Jaewon Kim
2020-03-29 7:19 ` Leon Romanovsky
2020-03-29 7:23 ` Greg KH
2020-03-29 8:19 ` Leon Romanovsky
2020-03-25 18:23 ` Alexey Dobriyan
2020-03-23 12:00 ` Dave Young
[not found] ` <CGME20200323080508epcas1p2dfe6517169a65936e5ab10c4e63a19a7@epcas1p2.samsung.com>
2020-03-23 8:05 ` [RFC PATCH v2 2/3] mm: zsmalloc: include zs page size in " Jaewon Kim
[not found] ` <CGME20200323080508epcas1p3c68190cd46635b9ff026a4ae70fc7a3b@epcas1p3.samsung.com>
2020-03-23 8:05 ` [RFC PATCH v2 3/3] android: ion: include system heap " Jaewon Kim
2020-03-23 9:49 ` Greg KH
2020-03-25 18:12 ` [RFC PATCH v2 0/3] meminfo_extra: introduce " Alexey Dobriyan
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