On Mon, Jul 30, 2018 at 10:53:53AM +0200, Vlastimil Babka wrote: > On 07/26/2018 06:26 PM, Alexey Dobriyan wrote: > > On Wed, Jul 25, 2018 at 08:53:53AM +0200, Vlastimil Babka wrote: > >> I moved the reply to this thread since the "added to -mm tree" > >> notification Alexey replied to in <20180724182908.GD27053@avx2> has > >> reduced CC list and is not linked to the patch postings. > >> > >> On 07/24/2018 08:29 PM, Alexey Dobriyan wrote: > >>> On Mon, Jul 23, 2018 at 04:55:48PM -0700, akpm@xxxxxxxxxxxxxxxxxxxx wrote: > >>>> The patch titled > >>>> Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file > >>>> has been added to the -mm tree. Its filename is > >>>> mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch > >>> > >>>> Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file > >>>> > >>>> The /proc/pid/smaps_rollup file is currently implemented via the > >>>> m_start/m_next/m_stop seq_file iterators shared with the other maps files, > >>>> that iterate over vma's. However, the rollup file doesn't print anything > >>>> for each vma, only accumulate the stats. > >>> > >>> What I don't understand why keep seq_ops then and not do all the work in > >>> ->show hook. Currently /proc/*/smaps_rollup is at ~500 bytes so with > >>> minimum 1 page seq buffer, no buffer resizing is possible. > >> > >> Hmm IIUC seq_file also provides the buffer and handles feeding the data > >> from there to the user process, which might have called read() with a smaller > >> buffer than that. So I would rather not avoid the seq_file infrastructure. > >> Or you're saying it could be converted to single_open()? Maybe, with more work. > > > > Prefereably yes. > > OK here it is. Sending as a new patch instead of delta, as that's easier > to review - the delta is significant. Line stats wise it's the same. > Again a bit less boilerplate thans to no special seq_ops, a bit more > copy/paste in the open and release functions. But I guess it's better > overall. > > ----8>---- > From c6a2eaf3bb3546509d6b7c42f8bcc56cd7e92f90 Mon Sep 17 00:00:00 2001 > From: Vlastimil Babka <vbabka@xxxxxxx> > Date: Wed, 18 Jul 2018 13:14:30 +0200 > Subject: [PATCH] mm: proc/pid/smaps_rollup: convert to single value seq_file Reviewed-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
