From: Ira Weiny <ira.weiny@intel.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Dan Williams <dan.j.williams@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V10 33/44] kmap: Make kmap work for devmap protected pages
Date: Thu, 19 May 2022 13:29:41 -0700 [thread overview]
Message-ID: <YoaotWPR0H5Mykff@iweiny-desk3> (raw)
In-Reply-To: <YoShWMGVj9ZJbWqT@infradead.org>
On Wed, May 18, 2022 at 12:33:44AM -0700, Christoph Hellwig wrote:
> On Tue, May 17, 2022 at 03:46:55PM -0700, Ira Weiny wrote:
> > Ok there is a trade off here which I'm not sure is a good idea.
> >
> > In order to make kmap faster I carefully placed the devmap_protected() call
> > completely inline.[1] This specifically checks the PGMAP_PROTECTION flag in
> > dev_pagemap.[1]
> >
> > I see only 2 ways of not including memremap.h in highmem-internal.h.
> >
> > 1) Make this check a function call and place it in memremap.c
> > 2) Move struct dev_pagemap (and it's dependencies) to another header.
> >
> > Number 2 negates any positive effect of splitting the header file.
> >
> > Number 1 is going to force some overhead on all ZONE_DEVICE pages if PMEM is in
> > the system.
> >
> > Do you think the extra run time overhead is a reasonable trade off to
> > eliminating the header?
>
> Well, given how big these devmap helpes are it seems like they should be
> out of line anyway due to the code size impact. It would be great to
> compare the code size for the cases of:
Fair enough. I did a few experiments with all yes config modified only to
remove LOCKDEP because those numbers were a bit skewed IMO.
>
> 1) baseline kernel
Text Data bss
293450036 337712849 19907196
> 2) devmap protection inline
This is V10
Text Data bss
293461422 337759561 19882620
From Baseline:
+ 11386 + 46712
0.0038% 0.014%
2.5) devmap partly inline (This cleans up the headers by adding a new header
for devmap protection and not using memremap.h in highmem-internal.h)
Text Data bss
293460722 337759593 19882620
From Baseline:
+ 10686 + 46744
0.0036% 0.014%
> 3) devmap protection out of line
Text Data bss
293458303 337734401 19890812
From Baseline:
+ 8267 + 21552
0.0028% 0.0064%
From these numbers it seems reasonable to have some of devmap_protected() out
of line to clean up the header dependencies.
Thanks,
Ira
next prev parent reply other threads:[~2022-05-19 20:29 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 17:06 [PATCH V10 00/44] PKS/PMEM: Add Stray Write Protection ira.weiny
2022-04-19 17:06 ` [PATCH V10 01/44] Documentation/protection-keys: Clean up documentation for User Space pkeys ira.weiny
2022-06-07 23:09 ` [tip: x86/mm] " tip-bot2 for Ira Weiny
2022-04-19 17:06 ` [PATCH V10 02/44] x86/pkeys: Clarify PKRU_AD_KEY macro ira.weiny
2022-06-07 23:09 ` [tip: x86/mm] " tip-bot2 for Ira Weiny
2022-04-19 17:06 ` [PATCH V10 03/44] x86/pkeys: Make PKRU macros generic ira.weiny
2022-04-19 17:06 ` [PATCH V10 04/44] x86/fpu: Refactor arch_set_user_pkey_access() ira.weiny
2022-04-19 17:06 ` [PATCH V10 05/44] mm/pkeys: Add Kconfig options for PKS ira.weiny
2022-04-19 17:06 ` [PATCH V10 06/44] x86/pkeys: Add PKS CPU feature bit ira.weiny
2022-04-19 17:06 ` [PATCH V10 07/44] x86/fault: Adjust WARN_ON for pkey fault ira.weiny
2022-04-19 17:06 ` [PATCH V10 08/44] Documentation/pkeys: Add initial PKS documentation ira.weiny
2022-05-09 22:03 ` Kees Cook
2022-05-10 17:18 ` Ira Weiny
2022-05-10 20:17 ` Kees Cook
2022-04-19 17:06 ` [PATCH V10 09/44] mm/pkeys: Provide for PKS key allocation ira.weiny
2022-04-19 17:06 ` [PATCH V10 10/44] x86/pkeys: Enable PKS on cpus which support it ira.weiny
2022-04-19 17:06 ` [PATCH V10 11/44] mm/pkeys: Define PKS page table macros ira.weiny
2022-04-19 17:06 ` [PATCH V10 12/44] x86/pkeys: Introduce pks_write_pkrs() ira.weiny
2022-04-19 17:06 ` [PATCH V10 13/44] x86/pkeys: Preserve the PKS MSR on context switch ira.weiny
2022-04-19 17:06 ` [PATCH V10 14/44] mm/pkeys: Introduce pks_set_readwrite() ira.weiny
2022-05-09 21:38 ` Kees Cook
2022-05-10 21:33 ` Ira Weiny
2022-05-10 22:08 ` Kees Cook
2022-05-10 22:26 ` Edgecombe, Rick P
2022-05-11 3:15 ` Kees Cook
2022-05-11 17:59 ` Ira Weiny
2022-04-19 17:06 ` [PATCH V10 15/44] mm/pkeys: Introduce pks_set_noaccess() ira.weiny
2022-04-19 17:06 ` [PATCH V10 16/44] mm/pkeys: Introduce PKS fault callbacks ira.weiny
2022-04-19 17:06 ` [PATCH V10 17/44] x86/entry: Add auxiliary pt_regs space ira.weiny
2022-04-19 17:06 ` [PATCH V10 18/44] entry: Pass pt_regs to irqentry_exit_cond_resched() ira.weiny
2022-04-19 17:06 ` [PATCH V10 19/44] entry: Add calls for save/restore auxiliary pt_regs ira.weiny
2022-04-19 17:06 ` [PATCH V10 20/44] x86/entry: Define arch_{save|restore}_auxiliary_pt_regs() ira.weiny
2022-04-19 17:06 ` [PATCH V10 21/44] x86/pkeys: Preserve PKRS MSR across exceptions ira.weiny
2022-04-19 17:06 ` [PATCH V10 22/44] x86/fault: Print PKS MSR on fault ira.weiny
2022-04-19 17:06 ` [PATCH V10 23/44] mm/pkeys: Introduce pks_update_exception() ira.weiny
2022-04-19 17:06 ` [PATCH V10 24/44] mm/pkeys: Add pks_available() ira.weiny
2022-04-19 17:06 ` [PATCH V10 25/44] memremap_pages: Add Kconfig for DEVMAP_ACCESS_PROTECTION ira.weiny
2022-04-19 17:06 ` [PATCH V10 26/44] memremap_pages: Introduce pgmap_protection_available() ira.weiny
2022-04-19 17:06 ` [PATCH V10 27/44] memremap_pages: Introduce a PGMAP_PROTECTION flag ira.weiny
2022-04-19 17:06 ` [PATCH V10 28/44] memremap_pages: Introduce devmap_protected() ira.weiny
2022-04-19 17:06 ` [PATCH V10 29/44] memremap_pages: Reserve a PKS pkey for eventual use by PMEM ira.weiny
2022-04-19 17:06 ` [PATCH V10 30/44] memremap_pages: Set PKS pkey in PTEs if requested ira.weiny
2022-04-19 17:06 ` [PATCH V10 31/44] memremap_pages: Define pgmap_set_{readwrite|noaccess}() calls ira.weiny
2022-04-19 17:06 ` [PATCH V10 32/44] memremap_pages: Add memremap.pks_fault_mode ira.weiny
2022-04-19 17:06 ` [PATCH V10 33/44] kmap: Make kmap work for devmap protected pages ira.weiny
2022-04-28 15:50 ` Christoph Hellwig
2022-05-12 1:25 ` Ira Weiny
2022-05-17 22:46 ` Ira Weiny
2022-05-18 7:33 ` Christoph Hellwig
2022-05-19 20:29 ` Ira Weiny [this message]
2022-04-19 17:06 ` [PATCH V10 34/44] dax: Stray access protection for dax_direct_access() ira.weiny
2022-04-19 17:06 ` [PATCH V10 35/44] nvdimm/pmem: Enable stray access protection ira.weiny
2022-04-19 17:06 ` [PATCH V10 36/44] devdax: " ira.weiny
2022-04-19 17:06 ` [PATCH V10 37/44] mm/pkeys: PKS testing, add initial test code ira.weiny
2022-04-19 17:06 ` [PATCH V10 38/44] x86/selftests: Add test_pks ira.weiny
2022-04-19 17:06 ` [PATCH V10 39/44] mm/pkeys: PKS testing, add a fault call back ira.weiny
2022-04-19 17:06 ` [PATCH V10 40/44] mm/pkeys: PKS testing, add pks_set_*() tests ira.weiny
2022-04-19 17:06 ` [PATCH V10 41/44] mm/pkeys: PKS testing, test context switching ira.weiny
2022-04-19 17:06 ` [PATCH V10 42/44] mm/pkeys: PKS testing, Add exception test ira.weiny
2022-04-19 17:06 ` [PATCH V10 43/44] mm/pkeys: PKS testing, test pks_update_exception() ira.weiny
2022-04-19 17:06 ` [PATCH V10 44/44] mm/pkeys: PKS testing, add test for all keys ira.weiny
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