On Wed, 16 Jan 2019, Matthew Wilcox wrote: > > On Thu, 17 Jan 2019, Linus Torvalds wrote: > > > As I suggested earlier in the thread, the fix for RWF_NOWAIT might be > > > to just move the test down to after readahead. > > Your patch 3/3 just removes the test. Am I right in thinking that it > doesn't need to be *moved* because the existing test after !PageUptodate > catches it?
Exactly. It just initiates read-ahead for IOCB_NOWAIT cases as well, and if it's actually set, it'll be handled by the !PageUpdtodate case. > Of course, there aren't any tests for RWF_NOWAIT in xfstests. Are there > any in LTP? Not in the released version AFAIK. I've asked the LTP maintainer (in our internal bugzilla) to take care of this thread a few days ago, but not sure what came out of it. Adding him (Cyril) to CC. > Some typos in the commit messages: > > > Another aproach (checking file access permissions in order to decide > "approach" > > > Subject: [PATCH 2/3] mm/mincore: make mincore() more conservative > > > > The semantics of what mincore() considers to be resident is not completely > > clearar, but Linux has always (since 2.3.52, which is when mincore() was > "clear" > > > initially done) treated it as "page is available in page cache". > > > > That's potentially a problem, as that [in]directly exposes meta-information > > about pagecache / memory mapping state even about memory not strictly > > belonging > > to the process executing the syscall, opening possibilities for sidechannel > > attacks. > > > > Change the semantics of mincore() so that it only reveals pagecache > > information > > for non-anonymous mappings that belog to files that the calling process > > could > "belong" Thanks. -- Jiri Kosina SUSE Labs
