From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Erdfelt Date: Tue, 31 Oct 2000 00:26:37 +0000 Subject: Re: [Linux-ia64] Re: IA-64 XFree86 (was: XFree 4.0.1 module loading) MIME-Version: 1 Content-Type: multipart/mixed; boundary="EVF5PPMfhYS0aIcm" Message-Id: List-Id: References: In-Reply-To: To: linux-ia64@vger.kernel.org --EVF5PPMfhYS0aIcm Content-Type: text/plain; charset=us-ascii On Mon, Aug 21, 2000, David Mosberger wrote: > Mark> 2) No mechanism for the X-server to write combine memory and > Mark> no discussions on adding this to Linux as far as I can tell. > Mark> There needs to be a new flag to open() or mmap(). There > Mark> aren't any MTRRs. > > I submitted a patch for the tdfx DRM module to map non-AGP stuff as > write-combined (actually, I'm not 100% sure this is the right thing to > do here; a DRM expert may want to double check this; it does seem to > work fine on my machine). See the latest Linux kernel patch. > > Linus already agreed that it would be OK to add additional mmap() > flags to indicate the memory attribute (normal vs. write-combine > vs. uncached). Walt says a patch to do this was developed as part of > the XFree86 4.0 work at VA and promised to send me a patch. I don't > think I have received such a patch, but I'd be happy to merge it > in. ;-) Now that we have a stable platform, we were able to test the patch and confirm the patch wasn't causing the stability problems we were seeing. This gets a 3 times speed improvement over non write combined memory in the tests Mark performed. The patch is against 2.4.0-test9-ia64-001004 JE --EVF5PPMfhYS0aIcm Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="mmap-wrcomb-noncached.patch" diff -ur linux-2.4.0-test9.orig/drivers/char/mem.c linux-2.4.0-test9/drivers/char/mem.c --- linux-2.4.0-test9.orig/drivers/char/mem.c Mon Sep 25 15:26:56 2000 +++ linux-2.4.0-test9/drivers/char/mem.c Thu Oct 26 15:31:18 2000 @@ -198,8 +198,12 @@ * through a file pointer that was marked O_SYNC will be * done non-cached. */ - if (noncached_address(offset) || (file->f_flags & O_SYNC)) + if (noncached_address(offset) || (file->f_flags & O_SYNC) || + vma->vm_flags & VM_NONCACHED) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + if (vma->vm_flags & VM_WRITECOMBINED) + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); /* * Don't dump addresses that are not real memory to a core file. diff -ur linux-2.4.0-test9.orig/include/asm-ia64/mman.h linux-2.4.0-test9/include/asm-ia64/mman.h --- linux-2.4.0-test9.orig/include/asm-ia64/mman.h Fri Apr 21 15:21:24 2000 +++ linux-2.4.0-test9/include/asm-ia64/mman.h Thu Oct 26 15:04:01 2000 @@ -24,6 +24,9 @@ #define MAP_LOCKED 0x2000 /* pages are locked */ #define MAP_NORESERVE 0x4000 /* don't check for reservations */ +#define MAP_WRITECOMBINED 0x10000 /* Write combine the area */ +#define MAP_NONCACHED 0x20000 /* Don't cache the memory */ + #define MS_ASYNC 1 /* sync memory asynchronously */ #define MS_INVALIDATE 2 /* invalidate the caches */ #define MS_SYNC 4 /* synchronous memory sync */ diff -ur linux-2.4.0-test9.orig/include/linux/mm.h linux-2.4.0-test9/include/linux/mm.h --- linux-2.4.0-test9.orig/include/linux/mm.h Mon Oct 2 11:01:19 2000 +++ linux-2.4.0-test9/include/linux/mm.h Thu Oct 26 15:30:56 2000 @@ -96,6 +96,9 @@ #define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */ #define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */ +#define VM_WRITECOMBINED 0x00100000 /* Write combined */ +#define VM_NONCACHED 0x00200000 /* Noncached access */ + #define VM_STACK_FLAGS 0x00000177 #define VM_READHINTMASK (VM_SEQ_READ | VM_RAND_READ) diff -ur linux-2.4.0-test9.orig/mm/mmap.c linux-2.4.0-test9/mm/mmap.c --- linux-2.4.0-test9.orig/mm/mmap.c Tue Aug 29 12:41:12 2000 +++ linux-2.4.0-test9/mm/mmap.c Mon Oct 30 11:01:13 2000 @@ -151,6 +151,12 @@ _trans(prot, PROT_WRITE, VM_WRITE) | _trans(prot, PROT_EXEC, VM_EXEC); flag_bits = +#ifdef MAP_WRITECOMBINED + _trans(flags, MAP_WRITECOMBINED, VM_WRITECOMBINED) | +#endif +#ifdef MAP_NONCACHED + _trans(flags, MAP_NONCACHED, VM_NONCACHED) | +#endif _trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) | _trans(flags, MAP_DENYWRITE, VM_DENYWRITE) | _trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE); --EVF5PPMfhYS0aIcm--