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Message-ID: <20160620131613.GD9892@dhcp22.suse.cz>
Date: Mon, 20 Jun 2016 15:16:14 +0200
From: Michal Hocko <mhocko@...nel.org>
To: Andy Lutomirski <luto@...nel.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
linux-arch@...r.kernel.org, Borislav Petkov <bp@...en8.de>,
Nadav Amit <nadav.amit@...il.com>,
Kees Cook <keescook@...omium.org>, Brian Gerst <brgerst@...il.com>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Josh Poimboeuf <jpoimboe@...hat.com>, Jann Horn <jann@...jh.net>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Vladimir Davydov <vdavydov@...tuozzo.com>,
Johannes Weiner <hannes@...xchg.org>, linux-mm@...ck.org
Subject: Re: [PATCH v2 04/13] mm: Track NR_KERNEL_STACK in KiB instead of
number of stacks
On Fri 17-06-16 13:00:40, Andy Lutomirski wrote:
> Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a
> zone. This only makes sense if each kernel stack exists entirely in
> one zone, and allowing vmapped stacks could break this assumption.
>
> Since frv has THREAD_SIZE < PAGE_SIZE, we need to track kernel stack
> allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on
> all architectures. Keep it simple and use KiB.
>
> Cc: Vladimir Davydov <vdavydov@...tuozzo.com>
> Cc: Johannes Weiner <hannes@...xchg.org>
> Cc: Michal Hocko <mhocko@...nel.org>
> Cc: linux-mm@...ck.org
> Signed-off-by: Andy Lutomirski <luto@...nel.org>
Makes sense to me.
Acked-by: Michal Hocko <mhocko@...e.com>
> ---
> drivers/base/node.c | 3 +--
> fs/proc/meminfo.c | 2 +-
> include/linux/mmzone.h | 2 +-
> kernel/fork.c | 3 ++-
> mm/page_alloc.c | 3 +--
> 5 files changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 560751bad294..27dc68a0ed2d 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -121,8 +121,7 @@ static ssize_t node_read_meminfo(struct device *dev,
> nid, K(node_page_state(nid, NR_FILE_MAPPED)),
> nid, K(node_page_state(nid, NR_ANON_PAGES)),
> nid, K(i.sharedram),
> - nid, node_page_state(nid, NR_KERNEL_STACK) *
> - THREAD_SIZE / 1024,
> + nid, node_page_state(nid, NR_KERNEL_STACK_KB),
> nid, K(node_page_state(nid, NR_PAGETABLE)),
> nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
> nid, K(node_page_state(nid, NR_BOUNCE)),
> diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
> index 83720460c5bc..239b5a06cee0 100644
> --- a/fs/proc/meminfo.c
> +++ b/fs/proc/meminfo.c
> @@ -145,7 +145,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
> global_page_state(NR_SLAB_UNRECLAIMABLE)),
> K(global_page_state(NR_SLAB_RECLAIMABLE)),
> K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
> - global_page_state(NR_KERNEL_STACK) * THREAD_SIZE / 1024,
> + global_page_state(NR_KERNEL_STACK_KB),
> K(global_page_state(NR_PAGETABLE)),
> #ifdef CONFIG_QUICKLIST
> K(quicklist_total_size()),
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 02069c23486d..63f05a7efb54 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -127,7 +127,7 @@ enum zone_stat_item {
> NR_SLAB_RECLAIMABLE,
> NR_SLAB_UNRECLAIMABLE,
> NR_PAGETABLE, /* used for pagetables */
> - NR_KERNEL_STACK,
> + NR_KERNEL_STACK_KB, /* measured in KiB */
> /* Second 128 byte cacheline */
> NR_UNSTABLE_NFS, /* NFS unstable pages */
> NR_BOUNCE,
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 5c2c355aa97f..be7f006af727 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -225,7 +225,8 @@ static void account_kernel_stack(struct thread_info *ti, int account)
> {
> struct zone *zone = page_zone(virt_to_page(ti));
>
> - mod_zone_page_state(zone, NR_KERNEL_STACK, account);
> + mod_zone_page_state(zone, NR_KERNEL_STACK_KB,
> + THREAD_SIZE / 1024 * account);
> }
>
> void free_task(struct task_struct *tsk)
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 6903b695ebae..a277dea926c9 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4457,8 +4457,7 @@ void show_free_areas(unsigned int filter)
> K(zone_page_state(zone, NR_SHMEM)),
> K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
> K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
> - zone_page_state(zone, NR_KERNEL_STACK) *
> - THREAD_SIZE / 1024,
> + zone_page_state(zone, NR_KERNEL_STACK_KB),
> K(zone_page_state(zone, NR_PAGETABLE)),
> K(zone_page_state(zone, NR_UNSTABLE_NFS)),
> K(zone_page_state(zone, NR_BOUNCE)),
> --
> 2.5.5
--
Michal Hocko
SUSE Labs
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