From: Andrew Morton <akpm@linux-foundation.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
linux-kernel@vger.kernel.org, lpk@581.spb.su,
wli@movementarian.org, torvalds@linux-foundation.org,
yinghan@google.com, Nick Piggin <npiggin@suse.de>,
Hugh Dickins <hugh@veritas.com>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 6/9] readahead: clean up and simplify the code for filemap page fault readahead
Date: Sat, 11 Apr 2009 11:49:20 -0700 [thread overview]
Message-ID: <20090411114920.b9d2493c.akpm@linux-foundation.org> (raw)
In-Reply-To: <2f11576a0904110658i4c595f49odbaefda8f8fa95d@mail.gmail.com>
On Sat, 11 Apr 2009 22:58:31 +0900 KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> > Ah. __But I have a note here that I didn't like it, because it adds lots
> > of new spinlocking to fastpaths. __So I'll leave things as they stand
> > until we have had a little talk about that.
>
> add?
>
> old code: grab zone->lru_lock via mark_page_accessed()
> new code: grab zone->lru_lock via update_reclaim_stat()
>
> one remove, one add.
>
mm-update_page_reclaim_stat-is-called-from-page-fault-path.patch adds
new calls to update_page_reclaim_stat() into do_swap_page() and
filemap_fault(). update_page_reclaim_stat() does spin_lock_irq() and
spin_unlock_irq(). It looks like a net slowdown to me.
> But I agree its lock can be removed maybe..
It would be nice to try to do something about it - every little bit
counts.
next prev parent reply other threads:[~2009-04-11 18:55 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-10 6:09 [PATCH 0/9] filemap and readahead fixes for linux-next Wu Fengguang
2009-04-10 6:09 ` [PATCH 1/9] readahead: move max_sane_readahead() calls into force_page_cache_readahead() Wu Fengguang
2009-04-10 6:09 ` [PATCH 2/9] readahead: apply max_sane_readahead() limit in ondemand_readahead() Wu Fengguang
2009-04-10 6:10 ` [PATCH 3/9] readahead: remove one unnecessary radix tree lookup Wu Fengguang
2009-04-10 6:10 ` [PATCH 4/9] readahead: increase interleaved readahead size Wu Fengguang
2009-04-10 6:10 ` [PATCH 5/9] readahead: remove sync/async readahead call dependency Wu Fengguang
2009-04-10 6:10 ` [PATCH 6/9] readahead: clean up and simplify the code for filemap page fault readahead Wu Fengguang
2009-04-10 23:48 ` Andrew Morton
2009-04-11 13:58 ` KOSAKI Motohiro
2009-04-11 18:49 ` Andrew Morton [this message]
2009-04-12 23:16 ` KOSAKI Motohiro
2009-04-10 6:10 ` [PATCH 7/9] readahead: sequential mmap readahead Wu Fengguang
2009-04-10 23:34 ` Andrew Morton
2009-04-12 6:50 ` Wu Fengguang
2009-04-12 7:09 ` [PATCH] readahead: enforce full sync mmap readahead size Wu Fengguang
2009-04-12 15:15 ` Linus Torvalds
2009-04-13 13:53 ` Wu Fengguang
2009-04-14 7:01 ` Nick Piggin
2009-04-10 6:10 ` [PATCH 8/9] readahead: enforce full readahead size on async mmap readahead Wu Fengguang
2009-04-10 6:10 ` [PATCH 9/9] readahead: record mmap read-around states in file_ra_state Wu Fengguang
2009-04-10 23:38 ` Andrew Morton
2009-04-11 4:24 ` Wu Fengguang
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