Messages in this thread | | | Date | Thu, 25 Aug 2005 11:20:54 +0200 | From | Eric Dumazet <> | Subject | Re: [PATCH] removes filp_count_lock and changes nr_files type to atomic_t |
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Arjan van de Ven a écrit : > On Thu, 2005-08-25 at 10:45 +0200, Eric Dumazet wrote: > >>This patch removes filp_count_lock spinlock, used to protect files_stat.nr_files. >> >>Just use atomic_t type and atomic_inc()/atomic_dec() operations. >> >>This patch assumes that atomic_read() is a plain {return v->counter;} on all >>architectures. (keywords : sysctl, /proc/sys/fs/file-nr, proc_dointvec) >> > > > this patch adds atomic ops where there were none before
nope... a spinlock/spinunlock contains atomic ops.
> for those architectures that need atomics for read (parisc? arm?)
not today. No atomic needed for read.
> > however.. wouldn't it be better to make this a per cpu variable for > write, and for read iterate or do something smart otherwise?
So on a machine with 256 CPUS, you want to iterate 256 counters ? nr_files is not heavily touched, no need to expand it.
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