lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 19 Feb 2012 13:21:02 -0800 (PST) From: Hugh Dickins <hughd@...gle.com> To: Naoya Horiguchi <n-horiguchi@...jp.nec.com> cc: linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>, David Rientjes <rientjes@...gle.com>, Andi Kleen <andi@...stfloor.org>, Wu Fengguang <fengguang.wu@...el.com>, Andrea Arcangeli <aarcange@...hat.com>, KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>, linux-kernel@...r.kernel.org Subject: Re: [PATCH 2/6] thp: optimize away unnecessary page table locking On Wed, 8 Feb 2012, Naoya Horiguchi wrote: > Currently when we check if we can handle thp as it is or we need to > split it into regular sized pages, we hold page table lock prior to > check whether a given pmd is mapping thp or not. Because of this, > when it's not "huge pmd" we suffer from unnecessary lock/unlock overhead. > To remove it, this patch introduces a optimized check function and > replace several similar logics with it. > > Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com> > Cc: David Rientjes <rientjes@...gle.com> > > Changes since v4: > - Rethink returned value of __pmd_trans_huge_lock() [snip] > --- 3.3-rc2.orig/mm/mremap.c > +++ 3.3-rc2/mm/mremap.c > @@ -155,8 +155,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma, > if (err > 0) { > need_flush = true; > continue; > - } else if (!err) { > - split_huge_page_pmd(vma->vm_mm, old_pmd); > } > VM_BUG_ON(pmd_trans_huge(*old_pmd)); > } Is that what you intended to do there? I just hit that VM_BUG_ON on rc3-next-20120217. Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists