[restore CC list] On Thu, May 31, 2012 at 08:25:09PM +0200, Michal Hocko wrote: > On Fri 01-06-12 00:01:29, Fengguang Wu wrote: > > On Thu, May 31, 2012 at 05:49:00PM +0200, Michal Hocko wrote: > > > On Thu 31-05-12 23:42:48, Fengguang Wu wrote: > > > > On Thu, May 31, 2012 at 05:32:49PM +0200, Michal Hocko wrote: > > > > > JFYI: You might have missed https://lkml.org/lkml/2012/5/31/122 because > > > > > intel mail server returned with "we do not like shell scripts as a > > > > > attachment". > > > > > > > > Yeah I did miss it.. A quick question: does the PageReclaim patch > > > > tested include the (priority < 3) test, or it's the originally posted > > > > patch? > > > > > > It's the original patch. > > > > OK, that's fine. I suspect even adding (priority < 3), it can help > > only some situations. In the others, the effect will be that writeback > > pages get accumulated in LRU until it starts to throttle page reclaims > > from both reads/writes. There will have to be some throttling somewhere. > > Yes, I agree. But it could help at least sporadic "hey this is a PageReclaim" > issues. I just didn't like to push priority into shrink_page_list > without. The justification is quite hard. Yeah priority is just a rule of thumb "there may be lots of dirty/writeback pages or other pressure if priority goes low". And it's already been used this way in shrink_page_list(). Considering that it's also targeting for -stable merge, we do need a very strict condition to safeguard no regressions on other cases. This is also true for the wait_iff_congested() scheme. > > Subject: mm: pass __GFP_WRITE to memcg charge and reclaim routines > > > > __GFP_WRITE will be tested in vmscan to find out the write tasks. > > > > For good interactive performance, we try to focus dirty reclaim waits on > > them and avoid blocking unrelated tasks. > > > > Signed-off-by: Fengguang Wu <fengguang.wu@xxxxxxxxx> > > I will have a look at this one tomorrow with a clean head. OK. The usage in my mind is if (PageWriteback(page) && PageReclaim(page)) + if ((sc->gfp_mask & __GFP_WAIT) || (priority < 3)) do some dirty throttling But note that it only detects writes to new pages (ie. simple dd). Overwrites to already cached clean pages cannot be detected this way.. Thanks, Fengguang > > --- > > include/linux/gfp.h | 2 +- > > mm/filemap.c | 17 ++++++++++------- > > 2 files changed, 11 insertions(+), 8 deletions(-) > > > > --- linux.orig/include/linux/gfp.h 2012-03-02 14:06:47.501765703 +0800 > > +++ linux/include/linux/gfp.h 2012-03-02 14:07:39.921766949 +0800 > > @@ -129,7 +129,7 @@ struct vm_area_struct; > > /* Control page allocator reclaim behavior */ > > #define GFP_RECLAIM_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS|\ > > __GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\ > > - __GFP_NORETRY|__GFP_NOMEMALLOC) > > + __GFP_NORETRY|__GFP_NOMEMALLOC|__GFP_WRITE) > > > > /* Control slab gfp mask during early boot */ > > #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_WAIT|__GFP_IO|__GFP_FS)) > > --- linux.orig/mm/filemap.c 2012-03-02 14:07:21.000000000 +0800 > > +++ linux/mm/filemap.c 2012-03-02 14:07:53.709767277 +0800 > > @@ -2339,23 +2339,26 @@ struct page *grab_cache_page_write_begin > > int status; > > gfp_t gfp_mask; > > struct page *page; > > - gfp_t gfp_notmask = 0; > > + gfp_t lru_gfp_mask = GFP_KERNEL; > > > > gfp_mask = mapping_gfp_mask(mapping); > > - if (mapping_cap_account_dirty(mapping)) > > + if (mapping_cap_account_dirty(mapping)) { > > gfp_mask |= __GFP_WRITE; > > - if (flags & AOP_FLAG_NOFS) > > - gfp_notmask = __GFP_FS; > > + lru_gfp_mask |= __GFP_WRITE; > > + } > > + if (flags & AOP_FLAG_NOFS) { > > + gfp_mask &= ~__GFP_FS; > > + lru_gfp_mask &= ~__GFP_FS; > > + } > > repeat: > > page = find_lock_page(mapping, index); > > if (page) > > goto found; > > > > - page = __page_cache_alloc(gfp_mask & ~gfp_notmask); > > + page = __page_cache_alloc(gfp_mask); > > if (!page) > > return NULL; > > - status = add_to_page_cache_lru(page, mapping, index, > > - GFP_KERNEL & ~gfp_notmask); > > + status = add_to_page_cache_lru(page, mapping, index, lru_gfp_mask); > > if (unlikely(status)) { > > page_cache_release(page); > > if (status == -EEXIST) > > > -- > Michal Hocko > SUSE Labs > SUSE LINUX s.r.o. > Lihovarska 1060/12 > 190 00 Praha 9 > Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>