lkml.org 
[lkml]   [2016]   [Oct]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm: remove unnecessary __get_user_pages_unlocked() calls
The holdout for unexporting __get_user_pages_unlocked() is its invocation in
mm/process_vm_access.c: process_vm_rw_single_vec(), as this definitely _does_
seem to invoke VM_FAULT_RETRY behaviour which get_user_pages_remote() will not
trigger if we were to replace it with the latter.

I'm not sure how to proceed in this case - get_user_pages_remote() invocations
assume mmap_sem is held so can't offer VM_FAULT_RETRY behaviour as the lock
can't be assumed to be safe to release, and get_user_pages_unlocked() assumes
tsk, mm are set to current, current->mm respectively so we can't use that here
either.

Is it important to retain VM_FAULT_RETRY behaviour here, does it matter? If it
isn't so important then we can just go ahead and replace with
get_user_pages_remote() and unexport away.

Of course the whole idea of unexporting __get_user_pages_unlocked() might be
bogus so let me know in that case also :)

\
 
 \ /
  Last update: 2016-10-26 01:47    [W:0.102 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site