Messages in this thread | | | Date | Wed, 15 Oct 2008 09:35:03 +0800 | From | Lai Jiangshan <> | Subject | Re: [PATCH 1/4] seq_file: don't call bitmap_scnprintf_len() |
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Lai Jiangshan wrote: > Alexey Dobriyan wrote: >> On Sun, Oct 12, 2008 at 05:29:17PM +0800, Lai Jiangshan wrote: >>> "m->count + len < m->size" is true commonly, so bitmap_scnprintf() >>> is commonly called. this fix saves a call to bitmap_scnprintf_len(). >> This saves a call if seq buffer is already full which is not a common >> situation, so you're optimising for rare situations and adding branch >> for common ones. > > Hi Alexey > > I think this saves a call if seq buffer is _not_ full after called. > > since calling bitmap_scnprintf() is the common situation. so we use > the return value of bitmap_scnprintf() instead of bitmap_scnprintf_len(). > > In old code bitmap_scnprintf_len() and bitmap_scnprintf() must be called > commonly. > > Thanks Lai.
Hi, Alexey,
Have noticed this comment? I hold my ground, ;-) And seq_cpumask_list(), seq_nodemask_list() are needed for print mask safely, Should I send independent patches for them if we can't make an agreement about this fix.
Lai
> >>> --- a/fs/seq_file.c >>> +++ b/fs/seq_file.c >>> @@ -452,17 +452,18 @@ int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc) >>> >>> int seq_bitmap(struct seq_file *m, unsigned long *bits, unsigned int nr_bits) >>> { >>> - size_t len = bitmap_scnprintf_len(nr_bits); >>> - >>> - if (m->count + len < m->size) { >>> - bitmap_scnprintf(m->buf + m->count, m->size - m->count, >>> - bits, nr_bits); >>> - m->count += len; >>> - return 0; >>> + if (m->count < m->size) { >>> + int len = bitmap_scnprintf(m->buf + m->count, >>> + m->size - m->count, bits, nr_bits); >>> + if (m->count + len < m->size) { >>> + m->count += len; >>> + return 0; >>> + } >>> } >>> m->count = m->size; >>> return -1; >>> } >>> +EXPORT_SYMBOL(seq_bitmap); >> Modular users, where are they? >> >> >> > >
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