From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sd0208e0.au.ibm.com (d23rh904.au.ibm.com [202.81.18.202]) by ausmtp04.au.ibm.com (8.13.8/8.13.8) with ESMTP id l0O5jdSl060546 for ; Wed, 24 Jan 2007 16:45:39 +1100 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.250.237]) by sd0208e0.au.ibm.com (8.13.8/8.13.8/NCO v8.2) with ESMTP id l0O5YbiQ239446 for ; Wed, 24 Jan 2007 16:34:37 +1100 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l0O5V7Qm016682 for ; Wed, 24 Jan 2007 16:31:08 +1100 Message-ID: <45B6EEFC.5050402@linux.vnet.ibm.com> Date: Wed, 24 Jan 2007 11:00:36 +0530 From: Vaidyanathan Srinivasan MIME-Version: 1.0 Subject: Re: [RPC][PATCH 2.6.20-rc5] limit total vfs page cache References: <6d6a94c50701171923g48c8652ayd281a10d1cb5dd95@mail.gmail.com> <45B0D967.8090607@linux.vnet.ibm.com> <6d6a94c50701190740v6da25151kb9ddcf358ab2957@mail.gmail.com> In-Reply-To: <6d6a94c50701190740v6da25151kb9ddcf358ab2957@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Aubrey Li Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andrew Morton , Nick Piggin , "linux-os (Dick Johnson)" , Robin Getz List-ID: Aubrey Li wrote: > On 1/19/07, Vaidyanathan Srinivasan wrote: >> Hi Aubrey, >> >> I used your patch on my PPC64 box and I do not get expected >> behavior. As you had requested, I am attaching zoneinfo and meminfo >> dumps: >> >> Please let me know if you need any further data to help me out with >> the test/experiment. >> > > Although I have no PPC64 box in hand, I think the logic should be the same. > get_page_from_freelist() is called 5 times in __alloc_pages(). > > 1) alloc_flags = ALLOC_WMARK_LOW | ALLOC_PAGECACHE; > 2) alloc_flags = ALLOC_WMARK_MIN | ALLOC_PAGECACHE; > We should have the same result on the first two times get_page_from_freelist(). > > 3) if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE))) > && !in_interrupt()) > alloc_flags = ALLOC_NO_WATERMARKS > The case on my platform will never enter this branch. If the branch > occurs on your side, > The limit will be omitted. Because NO watermark, zone_watermark_ok() > will not be checked. memory will be allocated directly. > > 4)if (likely(did_some_progress)) { > alloc_flags should include ALLOC_PAGECACHE. > So we should have the same result on this call. > > 5) } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) { > alloc_flags = ALLOC_WMARK_HIGH, without ALLOC_PAGECACHE > > This branch will not hit on my case. You may need to check it. > > If 3) or 5) occurs on your platform, I think you can easily fix it. > Please confirm it and let me know the result. None of the above condition was the problem in my PPC64 box. I added __GFP_PAGECACHE flag in pagecache_alloc_cold() and grab_cache_page_nowait() routines and the reclaim seemed to work. --- linux-2.6.20-rc5.orig/include/linux/pagemap.h +++ linux-2.6.20-rc5/include/linux/pagemap.h @@ -62,12 +62,12 @@ static inline struct page *__page_cache_ static inline struct page *page_cache_alloc(struct address_space *x) { - return __page_cache_alloc(mapping_gfp_mask(x)); + return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_PAGECACHE); } static inline struct page *page_cache_alloc_cold(struct address_space *x) { - return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD); + return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD|__GFP_PAGECACHE); } typedef int filler_t(void *, struct page *); [snip] --- linux-2.6.20-rc5.orig/mm/filemap.c +++ linux-2.6.20-rc5/mm/filemap.c @@ -823,7 +823,7 @@ grab_cache_page_nowait(struct address_sp page_cache_release(page); return NULL; } - page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); + page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS | __GFP_PAGECACHE); if (page && add_to_page_cache_lru(page, mapping, index, GFP_KERNEL)) { page_cache_release(page); page = NULL; pagecache_alloc_cold() is used in the read-ahead path which was being called in my case of large file operations. --Vaidy -- 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: email@kvack.org