[linux-mm-cc] [PATCH 01/12] clean up initialization

[Anderson Briglia]

Hi Munehiro,

I tried to apply this patch but I got some hunk's errors.
I'm using linux-kernel 2.6.21, patch-ccache-alpha-008-2.6.21 from CCache project's page and
UTIL-PATCH1_2-proc_entry_to_select_algo_ver2 and UTIL-PATCH2_2-proc_entry_to_select_algo_ver2 that you sent to
linux-mm-cc mailing list. Is this correct or should I apply some previous patch?

Cheers,

Anderson Briglia

ext IKEDA Munehiro wrote:
> This is code clean up patch for Ccache initialization part.
> This tries to make fs_backed and anon ccache procedures
> as symmetric as possible for readabiliby and maintenanceability.
> 
> In v1, should_add_to_ccache() was left as it was and
> the number of compressed anon pages can be negative improperly.
> This version fixed the bug.
> 
> Signed-off-by: IKEDA, Munehiro <m-ikeda at ds.jp.nec.com>
> ---
>  include/linux/ccache.h |    3 +--
>  mm/ccache.c            |   47 +++++++++++++++++++++++++++++++++++------------
>  mm/swapfile.c          |    6 ++----
>  3 files changed, 38 insertions(+), 18 deletions(-)
> 
> diff --git a/include/linux/ccache.h b/include/linux/ccache.h
> index 8aee787..31e3b49 100644
> --- a/include/linux/ccache.h
> +++ b/include/linux/ccache.h
> @@ -138,9 +138,8 @@ static inline void wait_on_chunk_head(unsigned long *flags)
>  #endif
>  }
>  
> -extern int init_ccache(void);
>  extern int is_page_in_virt_swap(struct page *page);
> -extern int set_anon_cc_size(unsigned long size);
> +extern int init_virt_swap(unsigned long size);
>  extern int should_add_to_ccache(struct page *page);
>  extern int cc_writepage(struct page *page);
>  extern struct page* handle_ccache_fault(struct chunk_head *ch,
> diff --git a/mm/ccache.c b/mm/ccache.c
> index 2d20b2c..cf315b0 100644
> --- a/mm/ccache.c
> +++ b/mm/ccache.c
> @@ -408,7 +408,7 @@ out:
>  	return len;
>  }
>  
> -int init_ccache(void)
> +static int init_ccache(void)
>  {
>  	if (anon_cc_started || fs_backed_cc_started) return 0;
>  
> @@ -442,6 +442,24 @@ int init_ccache(void)
>  	return 0;
>  }
>  
> +static int init_anon_ccache(unsigned long num)
> +{
> +	if (anon_cc_started)
> +		return 0;
> +
> +	init_ccache();
> +	return init_virt_swap(num);
> +}
> +
> +static int init_fs_backed_ccache(unsigned long num)
> +{
> +	if (fs_backed_cc_started)
> +		return 0;
> +
> +	init_ccache();
> +	return 0;
> +}
> +
>  int sysctl_max_anon_cc_size(ctl_table *table, int write,
>  	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
>  {
> @@ -461,9 +479,13 @@ int sysctl_max_anon_cc_size(ctl_table *table, int write,
>  	proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
>  	if (!write)
>  		goto out;
> -	ret = set_anon_cc_size(max_anon_cc_size);
> -	if (ret)
> +
> +	ret = init_anon_ccache(max_anon_cc_size);
> +	if (ret) {
> +		CC_INFO("Error Initializing anon ccache");
>  		goto out;
> +	}
> +
>  	CC_INFO("Max anon ccache size: %lu pages", max_anon_cc_size);
>  	anon_cc_started=1;
>  out:
> @@ -490,15 +512,14 @@ int sysctl_max_fs_backed_cc_size(ctl_table *table, int write,
>  	if (!write)
>  		goto out;
>  
> -	ret = init_ccache();
> +	ret = init_fs_backed_ccache(max_fs_backed_cc_size);
>  	if (ret) {
> -		CC_INFO("Error Initializing ccache");
> +		CC_INFO("Error Initializing fs_backed ccache");
>  		goto out;
>  	}
>  	
>  	CC_INFO("Max filesystem backed ccache size: %lu pages\n",
>  			max_fs_backed_cc_size);
> -	atomic_set(&fs_backed_cc_size, 0);
>  	fs_backed_cc_started = 1;
>  out:
>  	return ret;
> @@ -541,7 +562,8 @@ int should_add_to_ccache(struct page *page)
>  	if (anon_cc_started			&&
>  			PageSwapCache(page)	&&
>  			is_page_in_virt_swap(page)) {
> -		return 1;
> +		return atomic_add_unless(&anon_cc_size, 1,
> +				max_anon_cc_size);
>  	}
>  
>  	return 0;
> @@ -672,7 +694,9 @@ int cc_writepage(struct page *page)
>  	if (page_count(page) != 2) {
>  		CC_DEBUG2("(start) Page count not 2 (%d)"
>  			"flags=0x%08lx", page_count(page), page->flags);
> -		if (!PageSwapCache(page))
> +		if (PageSwapCache(page))
> +			atomic_dec(&anon_cc_size);
> +		else
>  			atomic_dec(&fs_backed_cc_size);
>  		return -EBUSY;
>  	}
> @@ -764,9 +788,6 @@ int cc_writepage(struct page *page)
>  	radix_tree_replace_slot((void **)slot, (void *)ch);
>  	CC_DEBUG2("after set slot");
>  
> -	if (PageSwapCache(page))
> -		atomic_inc(&anon_cc_size);
> -	
>  	/* or else it will be bad_page() when freed */
>  	page->mapping = NULL;
>  	ClearPageDirty(page);
> @@ -793,7 +814,9 @@ out_locked:
>  	write_unlock_irq(&mapping->tree_lock);
>  	CC_DEBUG2("in out_locked: after WUQ");
>  out:
> -	if (!PageSwapCache(page))
> +	if (PageSwapCache(page))
> +		atomic_dec(&anon_cc_size);
> +	else
>  		atomic_dec(&fs_backed_cc_size);
>  	if (ch)
>  		free_chunk_head(ch);
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index f2df6b2..c94a56f 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -1451,7 +1451,7 @@ int is_page_in_virt_swap(struct page *page)
>  	return 0;
>  }
>  
> -int set_anon_cc_size(unsigned long num_pages)
> +int init_virt_swap(unsigned long num_pages)
>  {
>  	int i, error, prev;
>  	unsigned int type;
> @@ -1459,8 +1459,6 @@ int set_anon_cc_size(unsigned long num_pages)
>  	struct swap_info_struct *p;
>  	struct swap_extent *new_se;
>  
> -	init_ccache();
> -
>  	error=0;
>  	spin_lock(&swap_lock);
>  	p = swap_info;
> @@ -1542,7 +1540,7 @@ out:
>  	return error;
>  }
>  
> -EXPORT_SYMBOL(set_anon_cc_size);
> +EXPORT_SYMBOL(init_virt_swap);
>  
>  /*
>   * Written 01/25/92 by Simmule Turner, heavily changed by Linus.