From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikita Danilov MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16781.436.710721.667909@gargle.gargle.HOWL> Date: Sat, 6 Nov 2004 19:54:12 +0300 Subject: Re: [PATCH] Remove OOM killer from try_to_free_pages / all_unreclaimable braindamage In-Reply-To: <20041106153209.GC3851@dualathlon.random> References: <20041105200118.GA20321@logos.cnet> <200411051532.51150.jbarnes@sgi.com> <20041106012018.GT8229@dualathlon.random> <418C2861.6030501@cyberone.com.au> <20041106015051.GU8229@dualathlon.random> <16780.46945.925271.26168@thebsh.namesys.com> <20041106153209.GC3851@dualathlon.random> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Nick Piggin , Jesse Barnes , Marcelo Tosatti , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Andrea Arcangeli writes: > On Sat, Nov 06, 2004 at 02:37:05PM +0300, Nikita Danilov wrote: > > We need page-reservation API of some sort. There were several attempts > > to introduce this, but none get into mainline. > > they're already in under the name of mempools I am talking about slightly different thing. Think of some operation that calls find_or_create_page(). find_or_create_page() doesn't know about memory reserved in mempools, it uses alloc_page() directly. If one wants to guarantee that compound operation has enough memory to complete, memory should be reserved at the lowest level---in the page allocator. > > I'm perfectly aware the fs tends to be the less correct places in terms > of allocations, and luckily it's not an heavy memory user, so I still Either you are kidding, or we are facing very different workloads. In the world of file-system development, file-system is (not surprisingly) single largest memory consumer. > have to see a deadlock in getblk or create_buffers or similar. It's > mostly a correctness issue (math proof it can't deadlock, right now it > can if more tasks all get stuck in getblk at the same time during a hard > oom condition etc..). Add here mmap that can dirty all physical memory behind your back, and delayed disk block allocation that forces ->writepage() to allocate potentially huge extent when memory is already tight and hope of having a proof becomes quite remote. Nikita. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org