Re: [PATCH] token based thrashing control
jhigdon_at_unixconfigs.org
Date: 07/31/04
- Previous message: David Brownell: "Re: Solving suspend-level confusion"
- In reply to: Rik van Riel: "[PATCH] token based thrashing control"
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Date: Fri, 30 Jul 2004 23:35:42 -0400 To: linux-kernel@vger.kernel.org
On Fri, Jul 30, 2004 at 05:37:18PM -0400, Rik van Riel wrote:
>
> The following experimental patch implements token based thrashing
> protection, using the algorithm described in:
>
> http://www.cs.wm.edu/~sjiang/token.htm
>
> When there are pageins going on, a task can grab a token, that
> protects the task from pageout (except by itself) until it is
> no longer doing heavy pageins, or until the maximum hold time
> of the token is over.
>
> If the maximum hold time is exceeded, the task isn't eligable
> to hold the token for a while more, since it wasn't doing it
> much good anyway.
>
> I have run a very unscientific benchmark on my system to test
> the effectiveness of the patch, timing how a 230MB two-process
> qsbench run takes, with and without the token thrashing
> protection present.
>
> normal 2.6.8-rc6: 6m45s
> 2.6.8-rc6 + token: 4m24s
>
> This is a quick hack, implemented without having talked to the
> inventor of the algorithm. He's copied on the mail and I suspect
> we'll be able to do better than my quick implementation ...
>
> Please test this patch.
Hello,
I tested this patch on my laptop which is a p2 400 and 128mb of ram.
After loading many applications far more then I usually do (fc2 running gnome2)
the application I currently use tends to be better responsiveness wise.
>
> include/linux/sched.h | 4 ++
> include/linux/swap.h | 21 ++++++++++
> kernel/fork.c | 2 +
> mm/Makefile | 2 -
> mm/filemap.c | 1
> mm/memory.c | 1
> mm/rmap.c | 3 +
> mm/thrash.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 8 files changed, 133 insertions(+), 1 deletion(-)
>
> --- linux-2.6.7/include/linux/swap.h.token 2004-07-30 13:22:17.000000000 -0400
> +++ linux-2.6.7/include/linux/swap.h 2004-07-30 16:39:27.000000000 -0400
> @@ -204,6 +204,27 @@
> extern struct page * lookup_swap_cache(swp_entry_t);
> extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,
> unsigned long addr);
> +/* linux/mm/thrash.c */
> +#ifdef CONFIG_SWAP
> +extern struct mm_struct * swap_token_mm;
> +extern void grab_swap_token(void);
> +extern void __put_swap_token(struct mm_struct *);
> +
> +static inline int has_swap_token(struct mm_struct * mm)
> +{
> + return (mm == swap_token_mm);
> +}
> +
> +static inline void put_swap_token(struct mm_struct * mm)
> +{
> + if (has_swap_token(mm))
> + __put_swap_token(mm);
> +}
> +#else /* CONFIG_SWAP */
> +#define put_swap_token do { } while(0)
> +#define grab_swap_token do { } while(0)
> +#define has_swap_token 0
> +#endif /* CONFIG_SWAP */
>
> /* linux/mm/swapfile.c */
> extern long total_swap_pages;
> --- linux-2.6.7/include/linux/sched.h.token 2004-07-30 13:22:28.000000000 -0400
> +++ linux-2.6.7/include/linux/sched.h 2004-07-30 13:22:29.000000000 -0400
> @@ -239,6 +239,10 @@
> /* Architecture-specific MM context */
> mm_context_t context;
>
> + /* Token based thrashing protection. */
> + unsigned long swap_token_time;
> + char recent_pagein;
> +
> /* coredumping support */
> int core_waiters;
> struct completion *core_startup_done, core_done;
> --- linux-2.6.7/kernel/fork.c.token 2004-07-30 13:22:27.000000000 -0400
> +++ linux-2.6.7/kernel/fork.c 2004-07-30 13:22:29.000000000 -0400
> @@ -36,6 +36,7 @@
> #include <linux/mount.h>
> #include <linux/audit.h>
> #include <linux/rmap.h>
> +#include <linux/swap.h>
>
> #include <asm/pgtable.h>
> #include <asm/pgalloc.h>
> @@ -463,6 +464,7 @@
> exit_aio(mm);
> exit_mmap(mm);
> mmdrop(mm);
> + put_swap_token(mm);
> }
> }
>
> --- linux-2.6.7/mm/memory.c.token 2004-07-30 13:22:28.000000000 -0400
> +++ linux-2.6.7/mm/memory.c 2004-07-30 13:22:29.000000000 -0400
> @@ -1433,6 +1433,7 @@
> /* Had to read the page from swap area: Major fault */
> ret = VM_FAULT_MAJOR;
> inc_page_state(pgmajfault);
> + grab_swap_token();
> }
>
> mark_page_accessed(page);
> --- linux-2.6.7/mm/filemap.c.token 2004-07-30 13:22:28.000000000 -0400
> +++ linux-2.6.7/mm/filemap.c 2004-07-30 13:22:29.000000000 -0400
> @@ -1195,6 +1195,7 @@
> * effect.
> */
> error = page_cache_read(file, pgoff);
> + grab_swap_token();
>
> /*
> * The page we want has now been added to the page cache.
> --- /dev/null 2003-09-15 09:40:47.000000000 -0400
> +++ linux-2.6.7/mm/thrash.c 2004-07-30 16:55:00.000000000 -0400
> @@ -0,0 +1,100 @@
> +/*
> + * mm/thrash.c
> + *
> + * Copyright (C) 2004, Red Hat, Inc.
> + * Copyright (C) 2004, Rik van Riel <riel@redhat.com>
> + * Released under the GPL, see the file COPYING for details.
> + *
> + * Simple token based thrashing protection, using the algorithm
> + * described in: http://www.cs.wm.edu/~sjiang/token.pdf
> + */
> +#include <linux/jiffies.h>
> +#include <linux/mm.h>
> +#include <linux/sched.h>
> +#include <linux/swap.h>
> +
> +static spinlock_t swap_token_lock = SPIN_LOCK_UNLOCKED;
> +static unsigned long swap_token_timeout;
> +unsigned long swap_token_check;
> +struct mm_struct * swap_token_mm = &init_mm;
> +
> +#define SWAP_TOKEN_CHECK_INTERVAL (HZ * 2)
> +#define SWAP_TOKEN_TIMEOUT (HZ * 300)
> +
> +/*
> + * Take the token away if the process had no page faults
> + * in the last interval, or if it has held the token for
> + * too long.
> + */
> +#define SWAP_TOKEN_ENOUGH_RSS 1
> +#define SWAP_TOKEN_TIMED_OUT 2
> +static int should_release_swap_token(struct mm_struct * mm)
> +{
> + int ret = 0;
> + if (!mm->recent_pagein)
> + ret = SWAP_TOKEN_ENOUGH_RSS;
> + else if (time_after(jiffies, swap_token_timeout))
> + ret = SWAP_TOKEN_TIMED_OUT;
> + mm->recent_pagein = 0;
> + return ret;
> +}
> +
> +/*
> + * Try to grab the swapout protection token. We only try to
> + * grab it once every TOKEN_CHECK_INTERVAL, both to prevent
> + * SMP lock contention and to check that the process that held
> + * the token before is no longer thrashing.
> + */
> +void grab_swap_token(void)
> +{
> + struct mm_struct * mm;
> + int reason;
> +
> + /* We have the token. Let others know we still need it. */
> + if (has_swap_token(current->mm)) {
> + current->mm->recent_pagein = 1;
> + return;
> + }
> +
> + if (time_after(jiffies, swap_token_check)) {
> +
> + /* Can't get swapout protection if we exceed our RSS limit. */
> + // if (current->mm->rss > current->mm->rlimit_rss)
> + // return;
> +
> + /* ... or if we recently held the token. */
> + if (time_before(jiffies, current->mm->swap_token_time))
> + return;
> +
> + if (!spin_trylock(&swap_token_lock))
> + return;
> +
> + swap_token_check = jiffies + SWAP_TOKEN_CHECK_INTERVAL;
> +
> + mm = swap_token_mm;
> + if ((reason = should_release_swap_token(mm))) {
> + unsigned long eligable = jiffies;
> + if (reason == SWAP_TOKEN_TIMED_OUT) {
> + eligable += SWAP_TOKEN_TIMEOUT;
> + }
> + mm->swap_token_time = eligable;
> + swap_token_timeout = jiffies + SWAP_TOKEN_TIMEOUT;
> + swap_token_mm = current->mm;
> + printk("Took swap token, pid %d (%s)\n",
> + current->pid, current->comm);
> + }
> + spin_unlock(&swap_token_lock);
> + }
> + return;
> +}
> +
> +/* Called on process exit. */
> +void __put_swap_token(struct mm_struct * mm)
> +{
> + spin_lock(&swap_token_lock);
> + if (mm == swap_token_mm) {
> + swap_token_mm = &init_mm;
> + swap_token_check = jiffies;
> + }
> + spin_unlock(&swap_token_lock);
> +}
> --- linux-2.6.7/mm/rmap.c.token 2004-07-30 13:22:24.000000000 -0400
> +++ linux-2.6.7/mm/rmap.c 2004-07-30 13:22:29.000000000 -0400
> @@ -230,6 +230,9 @@
> if (ptep_clear_flush_young(vma, address, pte))
> referenced++;
>
> + if (mm != current->mm && has_swap_token(mm))
> + referenced++;
> +
> (*mapcount)--;
>
> out_unmap:
> --- linux-2.6.7/mm/Makefile.token 2004-07-30 13:22:27.000000000 -0400
> +++ linux-2.6.7/mm/Makefile 2004-07-30 13:22:29.000000000 -0400
> @@ -12,7 +12,7 @@
> readahead.o slab.o swap.o truncate.o vmscan.o \
> $(mmu-y)
>
> -obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o
> +obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o
> obj-$(CONFIG_X86_4G) += usercopy.o
> obj-$(CONFIG_HUGETLBFS) += hugetlb.o
> obj-$(CONFIG_NUMA) += mempolicy.o
> --
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- Previous message: David Brownell: "Re: Solving suspend-level confusion"
- In reply to: Rik van Riel: "[PATCH] token based thrashing control"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
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