From: Jared Hulbert <jaredeh@gmail.com> To: "Wilcox, Matthew R" <matthew.r.wilcox@intel.com> Cc: Linux FS Devel <linux-fsdevel@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Linux Memory Management List <linux-mm@kvack.org>, Matthew Wilcox <willy@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>, Carsten Otte <cotte@de.ibm.com>, Chris Brandt <Chris.Brandt@renesas.com> Subject: Re: [PATCH v12 10/20] dax: Replace XIP documentation with DAX documentation Date: Sun, 24 Jan 2016 01:03:49 -0800 [thread overview] Message-ID: <CA+ZsKJ4EMKRgdFQzUjRJOE48=tTJzHf66-60PnVRj7pxvmNgVg@mail.gmail.com> (raw) In-Reply-To: <100D68C7BA14664A8938383216E40DE0421657C5@fmsmsx111.amr.corp.intel.com> I our defense we didn't know we were sinning at the time. Can you walk me through the cache flushing hole? How is it okay on X86 but not VIVT archs? I'm missing something obvious here. I thought earlier that vm_insert_mixed() handled the necessary flushing. Is that even the part you are worried about? vm_insert_mixed()->insert_pfn()->update_mmu_cache() _should_ handle the flush. Except of course now that I look at the ARM code it looks like it isn't doing anything if !pfn_valid(). <sigh> I need to spend some more time looking at this again. What flushing functions would you call if you did have a cache page. There are all kinds of cache flushing functions that work without a struct page. If nothing else the specialized ASM instructions that do the various flushes don't use struct page as a parameter. This isn't the first I've run into the lack of a sane cache API. Grep for inval_cache in the mtd drivers, should have been much easier. Isn't the proper solution to fix update_mmu_cache() or build out a pageless cache flushing API? I don't get the explicit mapping solution. What are you mapping where? What addresses would be SHMLBA? Phys, kernel, userspace?
WARNING: multiple messages have this Message-ID (diff)
From: Jared Hulbert <jaredeh@gmail.com> To: "Wilcox, Matthew R" <matthew.r.wilcox@intel.com> Cc: Linux FS Devel <linux-fsdevel@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Linux Memory Management List <linux-mm@kvack.org>, Matthew Wilcox <willy@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>, Carsten Otte <cotte@de.ibm.com>, Chris Brandt <Chris.Brandt@renesas.com> Subject: Re: [PATCH v12 10/20] dax: Replace XIP documentation with DAX documentation Date: Sun, 24 Jan 2016 01:03:49 -0800 [thread overview] Message-ID: <CA+ZsKJ4EMKRgdFQzUjRJOE48=tTJzHf66-60PnVRj7pxvmNgVg@mail.gmail.com> (raw) In-Reply-To: <100D68C7BA14664A8938383216E40DE0421657C5@fmsmsx111.amr.corp.intel.com> I our defense we didn't know we were sinning at the time. Can you walk me through the cache flushing hole? How is it okay on X86 but not VIVT archs? I'm missing something obvious here. I thought earlier that vm_insert_mixed() handled the necessary flushing. Is that even the part you are worried about? vm_insert_mixed()->insert_pfn()->update_mmu_cache() _should_ handle the flush. Except of course now that I look at the ARM code it looks like it isn't doing anything if !pfn_valid(). <sigh> I need to spend some more time looking at this again. What flushing functions would you call if you did have a cache page. There are all kinds of cache flushing functions that work without a struct page. If nothing else the specialized ASM instructions that do the various flushes don't use struct page as a parameter. This isn't the first I've run into the lack of a sane cache API. Grep for inval_cache in the mtd drivers, should have been much easier. Isn't the proper solution to fix update_mmu_cache() or build out a pageless cache flushing API? I don't get the explicit mapping solution. What are you mapping where? What addresses would be SHMLBA? Phys, kernel, userspace? -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-01-24 9:03 UTC|newest] Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-10-24 21:20 [PATCH v12 00/20] DAX: Page cache bypass for filesystems on memory storage Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 01/20] axonram: Fix bug in direct_access Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 02/20] block: Change direct_access calling convention Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 03/20] mm: Fix XIP fault vs truncate race Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton 2015-01-13 18:50 ` Matthew Wilcox 2015-01-13 18:50 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 04/20] mm: Allow page fault handlers to perform the COW Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton 2015-01-13 18:58 ` Matthew Wilcox 2015-01-13 18:58 ` Matthew Wilcox 2015-02-05 9:16 ` Yigal Korman 2015-02-05 9:16 ` Yigal Korman 2015-02-05 21:39 ` Matthew Wilcox 2015-02-05 21:39 ` Matthew Wilcox 2015-02-08 11:48 ` Yigal Korman 2015-02-08 11:48 ` Yigal Korman 2014-10-24 21:20 ` [PATCH v12 05/20] vfs,ext2: Introduce IS_DAX(inode) Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 06/20] dax,ext2: Replace XIP read and write with DAX I/O Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton 2015-01-13 20:59 ` Matthew Wilcox 2015-01-13 20:59 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 07/20] dax,ext2: Replace ext2_clear_xip_target with dax_clear_blocks Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton 2015-01-13 21:39 ` Matthew Wilcox 2015-01-13 21:39 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 08/20] dax,ext2: Replace the XIP page fault handler with the DAX page fault handler Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton 2015-01-13 21:53 ` Matthew Wilcox 2015-01-13 21:53 ` Matthew Wilcox 2015-01-13 22:47 ` Andrew Morton 2015-01-13 22:47 ` Andrew Morton 2014-10-24 21:20 ` [PATCH v12 09/20] dax,ext2: Replace xip_truncate_page with dax_truncate_page Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton 2015-01-13 21:55 ` Matthew Wilcox 2015-01-13 21:55 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 10/20] dax: Replace XIP documentation with DAX documentation Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:10 ` Andrew Morton 2015-01-12 23:10 ` Andrew Morton 2016-01-21 18:38 ` Jared Hulbert 2016-01-21 18:38 ` Jared Hulbert 2016-01-22 13:07 ` Wilcox, Matthew R 2016-01-22 13:48 ` Chris Brandt 2016-01-22 14:39 ` Matthew Wilcox 2016-01-22 14:39 ` Matthew Wilcox 2016-01-24 9:03 ` Jared Hulbert [this message] 2016-01-24 9:03 ` Jared Hulbert 2016-01-25 16:52 ` Matthew Wilcox 2016-01-25 16:52 ` Matthew Wilcox 2016-01-25 21:18 ` Jared Hulbert 2016-01-25 21:18 ` Jared Hulbert 2016-01-27 19:51 ` Jared Hulbert 2016-01-27 19:51 ` Jared Hulbert 2014-10-24 21:20 ` [PATCH v12 11/20] vfs: Remove get_xip_mem Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 12/20] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 13/20] ext2: Remove ext2_use_xip Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 14/20] ext2: Remove xip.c and xip.h Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 15/20] vfs,ext2: Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 16/20] ext2: Remove ext2_aops_xip Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 17/20] ext2: Get rid of most mentions of XIP in ext2 Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 18/20] dax: Add dax_zero_page_range Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2015-01-12 23:10 ` Andrew Morton 2015-01-12 23:10 ` Andrew Morton 2015-01-12 23:20 ` Ross Zwisler 2015-01-12 23:20 ` Ross Zwisler 2015-01-12 23:20 ` Ross Zwisler 2014-10-24 21:20 ` [PATCH v12 19/20] ext4: Add DAX functionality Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-10-24 21:20 ` [PATCH v12 20/20] brd: Rename XIP to DAX Matthew Wilcox 2014-10-24 21:20 ` Matthew Wilcox 2014-12-10 14:03 ` [PATCH v12 00/20] DAX: Page cache bypass for filesystems on memory storage Christoph Hellwig 2014-12-10 14:03 ` Christoph Hellwig 2014-12-10 14:12 ` Matthew Wilcox 2014-12-10 14:12 ` Matthew Wilcox 2014-12-10 14:28 ` Jeff Moyer 2014-12-10 14:28 ` Jeff Moyer 2014-12-10 20:53 ` Dave Chinner 2014-12-10 20:53 ` Dave Chinner 2015-01-05 18:41 ` Christoph Hellwig 2015-01-05 18:41 ` Christoph Hellwig 2015-01-06 8:47 ` Andrew Morton 2015-01-06 8:47 ` Andrew Morton 2015-01-08 11:49 ` pread2/ pwrite2 Christoph Hellwig 2015-01-08 11:49 ` Christoph Hellwig 2015-01-09 19:30 ` Steve French 2015-01-09 19:30 ` Steve French 2015-01-08 16:27 ` [PATCH v12 00/20] DAX: Page cache bypass for filesystems on memory storage Milosz Tanski 2015-01-08 16:28 ` Milosz Tanski 2015-01-08 16:28 ` Milosz Tanski 2015-01-08 17:36 ` Jeremy Allison 2015-01-08 17:36 ` Jeremy Allison 2015-01-12 14:47 ` Matthew Wilcox 2015-01-12 14:47 ` Matthew Wilcox 2015-01-12 23:09 ` Andrew Morton 2015-01-12 23:09 ` Andrew Morton
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