On Mon, May 19, 2014 at 11:03:11PM -0700, Andrew Morton wrote: > On Mon, 19 May 2014 22:59:15 -0700 Andrew Morton <[email protected]> > wrote: > > > On Tue, 20 May 2014 10:44:49 +1000 Dave Chinner <[email protected]> wrote: > > > > > @@ -258,14 +258,23 @@ xfs_bmapi_allocate_worker( > > > struct xfs_bmalloca *args = container_of(work, > > > struct xfs_bmalloca, work); > > > unsigned long pflags; > > > + unsigned long new_pflags = PF_FSTRANS; > > > > > > - /* we are in a transaction context here */ > > > - current_set_flags_nested(&pflags, PF_FSTRANS); > > > + /* > > > + * we are in a transaction context here, but may also be doing work > > > + * in kswapd context, and hence we may need to inherit that state > > > + * temporarily to ensure that we don't block waiting for memory reclaim > > > + * in any way. > > > + */ > > > + if (args->kswapd) > > > + new_pflags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; > > > > So current_is_kswapd() returns true for a thread which is not kswapd. > > That's a bit smelly. > > > > Should this thread really be incrementing KSWAPD_INODESTEAL instead of > > PGINODESTEAL, for example? current_is_kswapd() does a range of things, > > only one(?) of which you actually want. > > > > It would be cleaner to create a new PF_ flag to select just that > > behavior. That's a better model than telling the world "I am magic and > > special". > > Or a new __GFP_FLAG.
Sure - and with that XFS will need another PF_ flag to tell the memory allocator to set the new __GFP_FLAG on every allocation done in that kworker task context, just like it uses PF_FSTRANS to ensure that __GFP_NOFS is set for all the allocations in that kworker context.... Cheers, Dave. -- Dave Chinner [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
