Re: [PATCH] mm: don't cap request size based on read-ahead setting

2016-11-21 Thread Jens Axboe
On 11/20/2016 09:44 PM, Hillf Danton wrote: On Saturday, November 19, 2016 3:41 AM Jens Axboe wrote: We ran into a funky issue, where someone doing 256K buffered reads saw 128K requests at the device level. Turns out it is read-ahead capping the request size, since we use 128K as the default set

Re: [PATCH] mm: don't cap request size based on read-ahead setting

2016-11-20 Thread Hillf Danton
On Saturday, November 19, 2016 3:41 AM Jens Axboe wrote: > We ran into a funky issue, where someone doing 256K buffered reads saw > 128K requests at the device level. Turns out it is read-ahead capping > the request size, since we use 128K as the default setting. This doesn't > make a lot of sense

[PATCH] mm: don't cap request size based on read-ahead setting

2016-11-18 Thread Jens Axboe
We ran into a funky issue, where someone doing 256K buffered reads saw 128K requests at the device level. Turns out it is read-ahead capping the request size, since we use 128K as the default setting. This doesn't make a lot of sense - if someone is issuing 256K reads, they should see 256K reads, r

Re: [PATCH] mm: don't cap request size based on read-ahead setting

2016-11-16 Thread Jens Axboe
On 11/16/2016 08:12 AM, Jens Axboe wrote: On 11/16/2016 12:17 AM, Hillf Danton wrote: On Wednesday, November 16, 2016 12:31 PM Jens Axboe wrote: @@ -369,10 +369,25 @@ ondemand_readahead(struct address_space *mapping, bool hit_readahead_marker, pgoff_t offset, unsigned

Re: [PATCH] mm: don't cap request size based on read-ahead setting

2016-11-16 Thread Jens Axboe
On 11/16/2016 12:17 AM, Hillf Danton wrote: On Wednesday, November 16, 2016 12:31 PM Jens Axboe wrote: @@ -369,10 +369,25 @@ ondemand_readahead(struct address_space *mapping, bool hit_readahead_marker, pgoff_t offset, unsigned long req_size) { - unsi

Re: [PATCH] mm: don't cap request size based on read-ahead setting

2016-11-15 Thread Hillf Danton
On Wednesday, November 16, 2016 12:31 PM Jens Axboe wrote: > @@ -369,10 +369,25 @@ ondemand_readahead(struct address_space *mapping, > bool hit_readahead_marker, pgoff_t offset, > unsigned long req_size) > { > - unsigned long max = ra->ra_pages; > + unsig

[PATCH] mm: don't cap request size based on read-ahead setting

2016-11-15 Thread Jens Axboe
Hi, We ran into a funky issue, where someone doing 256K buffered reads saw 128K requests at the device level. Turns out it is read-ahead capping the request size, since we use 128K as the default setting. This doesn't make a lot of sense - if someone is issuing 256K reads, they should see 256K re