From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 23 Apr 2018 09:04:35 -0600 From: Michal Hocko To: kirill.shutemov@linux.intel.com, Yang Shi Cc: hughd@google.com, hch@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC v2 PATCH] mm: shmem: make stat.st_blksize return huge page size if THP is on Message-ID: <20180423150435.GS17484@dhcp22.suse.cz> References: <1524242039-64997-1-git-send-email-yang.shi@linux.alibaba.com> <20180423004748.GP17484@dhcp22.suse.cz> <3c59a1d1-dc66-ae5f-452c-dd0adb047433@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3c59a1d1-dc66-ae5f-452c-dd0adb047433@linux.alibaba.com> Sender: owner-linux-mm@kvack.org List-ID: On Sun 22-04-18 21:28:59, Yang Shi wrote: > > > On 4/22/18 6:47 PM, Michal Hocko wrote: [...] > > will be used on the first aligned address even when the initial/last > > portion of the mapping is not THP aligned. > > No, my test shows it is not. And, transhuge_vma_suitable() does check the > virtual address alignment. If it is not huge page size aligned, it will not > set PMD for huge page. It's been quite some time since I've looked at that code but I think you are wrong. It just doesn't make sense to make the THP decision on the VMA alignment much. Kirill, can you clarify please? Please note that I have no objections to actually export the huge page size as the max block size but your changelog just doesn't make any sense to me. -- Michal Hocko SUSE Labs