linux-kernel - Re: [PATCH v6 07/19] mm: Put readahead pages in cache earlier

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <61bcaa87-91b2-857b-350a-86dab81a1f13@nvidia.com>
Date:   Tue, 18 Feb 2020 17:13:08 -0800
From:   John Hubbard <jhubbard@...dia.com>
To:     Matthew Wilcox <willy@...radead.org>
CC:     <linux-fsdevel@...r.kernel.org>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linux-btrfs@...r.kernel.org>,
        <linux-erofs@...ts.ozlabs.org>, <linux-ext4@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>,
        <cluster-devel@...hat.com>, <ocfs2-devel@....oracle.com>,
        <linux-xfs@...r.kernel.org>
Subject: Re: [PATCH v6 07/19] mm: Put readahead pages in cache earlier

On 2/18/20 5:02 PM, Matthew Wilcox wrote:
> On Tue, Feb 18, 2020 at 04:01:43PM -0800, John Hubbard wrote:
>> How about this instead? It uses the "for" loop fully and more naturally,
>> and is easier to read. And it does the same thing:
>>
>> static inline struct page *readahead_page(struct readahead_control *rac)
>> {
>> 	struct page *page;
>>
>> 	if (!rac->_nr_pages)
>> 		return NULL;
>>
>> 	page = xa_load(&rac->mapping->i_pages, rac->_start);
>> 	VM_BUG_ON_PAGE(!PageLocked(page), page);
>> 	rac->_batch_count = hpage_nr_pages(page);
>>
>> 	return page;
>> }
>>
>> static inline struct page *readahead_next(struct readahead_control *rac)
>> {
>> 	rac->_nr_pages -= rac->_batch_count;
>> 	rac->_start += rac->_batch_count;
>>
>> 	return readahead_page(rac);
>> }
>>
>> #define readahead_for_each(rac, page)			\
>> 	for (page = readahead_page(rac); page != NULL;	\
>> 	     page = readahead_page(rac))
> 
> I'm assuming you mean 'page = readahead_next(rac)' on that second line.


Yep. :)


> 
> If you keep reading all the way to the penultimate patch, it won't work
> for iomap ... at least not in the same way.
> 

OK, getting there...


thanks,
-- 
John Hubbard
NVIDIA