From: David Rientjes <rientjes@google.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
ben.widawsky@intel.com, alex.shi@linux.alibaba.com,
dwagner@suse.de, tobin@kernel.org, cl@linux.com,
akpm@linux-foundation.org, ying.huang@intel.com,
dan.j.williams@intel.com, cai@lca.pw
Subject: Re: [PATCH 3/3] mm/vmscan: replace implicit RECLAIM_ZONE checks with explicit checks
Date: Wed, 1 Jul 2020 13:03:01 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.23.453.2007011256280.1908531@chino.kir.corp.google.com> (raw)
In-Reply-To: <20200701152627.8761147E@viggo.jf.intel.com>
On Wed, 1 Jul 2020, Dave Hansen wrote:
> diff -puN include/linux/swap.h~mm-vmscan-node_reclaim_mode_helper include/linux/swap.h
> --- a/include/linux/swap.h~mm-vmscan-node_reclaim_mode_helper 2020-07-01 08:22:13.650955330 -0700
> +++ b/include/linux/swap.h 2020-07-01 08:22:13.659955330 -0700
> @@ -12,6 +12,7 @@
> #include <linux/fs.h>
> #include <linux/atomic.h>
> #include <linux/page-flags.h>
> +#include <uapi/linux/mempolicy.h>
> #include <asm/page.h>
>
> struct notifier_block;
> @@ -374,6 +375,12 @@ extern int sysctl_min_slab_ratio;
> #define node_reclaim_mode 0
> #endif
>
> +static inline bool node_reclaim_enabled(void)
> +{
> + /* Is any node_reclaim_mode bit set? */
> + return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
> +}
> +
> extern void check_move_unevictable_pages(struct pagevec *pvec);
>
> extern int kswapd_run(int nid);
If a user writes a bit that isn't a RECLAIM_* bit to vm.zone_reclaim_mode
today, it acts as though RECLAIM_ZONE is enabled: we try to reclaim in
zonelist order before falling back to the next zone in the page allocator.
The sysctl doesn't enforce any max value :/ I dont know if there is any
such user, but this would break them if there is.
Should this simply be return !!node_reclaim_mode?
next prev parent reply other threads:[~2020-07-01 20:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-01 15:26 [PATCH 0/3] [v2] Repair and clean up vm.zone_reclaim_mode sysctl ABI Dave Hansen
2020-07-01 15:26 ` [PATCH 1/3] mm/vmscan: restore zone_reclaim_mode ABI Dave Hansen
2020-07-01 20:03 ` David Rientjes
2020-07-02 11:28 ` Huang, Ying
2020-07-02 14:36 ` Dave Hansen
2020-07-01 15:26 ` [PATCH 2/3] mm/vmscan: move RECLAIM* bits to uapi header Dave Hansen
2020-07-01 15:46 ` Ben Widawsky
2020-07-01 15:56 ` Dave Hansen
2020-07-01 20:03 ` David Rientjes
2020-07-01 15:26 ` [PATCH 3/3] mm/vmscan: replace implicit RECLAIM_ZONE checks with explicit checks Dave Hansen
2020-07-01 20:03 ` David Rientjes [this message]
2020-07-01 20:04 ` Ben Widawsky
2020-07-01 21:29 ` Dave Hansen
2020-07-01 22:01 ` David Rientjes
2020-07-01 16:00 ` [PATCH 0/3] [v2] Repair and clean up vm.zone_reclaim_mode sysctl ABI Ben Widawsky
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