From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 18 Dec 2004 02:45:22 -0800 From: William Lee Irwin III Subject: Re: [PATCH 4/10] alternate 4-level page tables patches Message-ID: <20041218104522.GI771@holomorphy.com> References: <41C3D453.4040208@yahoo.com.au> <41C3D479.40708@yahoo.com.au> <41C3D48F.8080006@yahoo.com.au> <41C3D4AE.7010502@yahoo.com.au> <41C3D4C8.1000508@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41C3D4C8.1000508@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Linux Memory Management , Andi Kleen , Hugh Dickins , Linus Torvalds , Andrew Morton List-ID: On Sat, Dec 18, 2004 at 05:57:12PM +1100, Nick Piggin wrote: > Rename clear_page_tables to clear_page_range. clear_page_range takes byte > ranges, and aggressively frees page table pages. Maybe useful to control > page table memory consumption on 4-level architectures (and even 3 level > ones). > Possible downsides are: > - flush_tlb_pgtables gets called more often (only a problem for sparc64 > AFAIKS). > - the opportunistic "expand to fill PGDIR_SIZE hole" logic that ensures > something actually gets done under the old system is still in place. > This could sometimes make unmapping small regions more inefficient. There > are some other solutions to look at if this is the case though. > Signed-off-by: Nick Piggin I wrote something equivalent to this in September, but dropped it on the floor after some private replies etc. indicated no one gave a damn about the testcase I posted in Message-ID: <20040908110718.GX3106@holomorphy.com> where the pagetable leak fooled the OOM killer into shooting the wrong processes long enough to trigger a panic() in oom_kill.c -- wli -- 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