* [PATCH] m68k: One function call less in cf_tlb_miss() @ 2019-07-05 15:18 Markus Elfring 2019-07-05 23:56 ` Finn Thain 0 siblings, 1 reply; 6+ messages in thread From: Markus Elfring @ 2019-07-05 15:18 UTC (permalink / raw) To: linux-m68k, Andrew Morton, Geert Uytterhoeven, Greg Ungerer, Michal Hocko, Mike Rapoport Cc: LKML, kernel-janitors From: Markus Elfring <elfring@users.sourceforge.net> Date: Fri, 5 Jul 2019 17:11:37 +0200 Avoid an extra function call by using a ternary operator instead of a conditional statement for a setting selection. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> --- arch/m68k/mm/mcfmmu.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c index 6cb1e41d58d0..02fc0778028e 100644 --- a/arch/m68k/mm/mcfmmu.c +++ b/arch/m68k/mm/mcfmmu.c @@ -146,12 +146,10 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); - - if (dtlb) - mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); - else - mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); - + mmu_write(MMUOR, + dtlb + ? MMUOR_ACC | MMUOR_UAA + : MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); local_irq_restore(flags); return 0; } -- 2.22.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] m68k: One function call less in cf_tlb_miss() 2019-07-05 15:18 [PATCH] m68k: One function call less in cf_tlb_miss() Markus Elfring @ 2019-07-05 23:56 ` Finn Thain 2019-07-14 13:23 ` Geert Uytterhoeven 0 siblings, 1 reply; 6+ messages in thread From: Finn Thain @ 2019-07-05 23:56 UTC (permalink / raw) To: Markus Elfring Cc: linux-m68k, Andrew Morton, Geert Uytterhoeven, Greg Ungerer, Michal Hocko, Mike Rapoport, LKML, kernel-janitors On Fri, 5 Jul 2019, Markus Elfring wrote: > From: Markus Elfring <elfring@users.sourceforge.net> > Date: Fri, 5 Jul 2019 17:11:37 +0200 > > Avoid an extra function call Not really. You've avoided an extra statement. > by using a ternary operator instead of a conditional statement for a > setting selection. > > This issue was detected by using the Coccinelle software. > > Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> > --- > arch/m68k/mm/mcfmmu.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c > index 6cb1e41d58d0..02fc0778028e 100644 > --- a/arch/m68k/mm/mcfmmu.c > +++ b/arch/m68k/mm/mcfmmu.c > @@ -146,12 +146,10 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) > > mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | > ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); > - > - if (dtlb) > - mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); > - else > - mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); > - > + mmu_write(MMUOR, > + dtlb > + ? MMUOR_ACC | MMUOR_UAA > + : MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); If you are trying to avoid redundancy, why not finish the job? + mmu_write(MMUOR, (dtlb ? 0 : MMUOR_ITLB) | MMUOR_ACC | MMUOR_UAA); -- > local_irq_restore(flags); > return 0; > } > -- > 2.22.0 > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] m68k: One function call less in cf_tlb_miss() 2019-07-05 23:56 ` Finn Thain @ 2019-07-14 13:23 ` Geert Uytterhoeven 2019-07-14 16:05 ` Markus Elfring 0 siblings, 1 reply; 6+ messages in thread From: Geert Uytterhoeven @ 2019-07-14 13:23 UTC (permalink / raw) To: Markus Elfring Cc: Finn Thain, Andrew Morton, Greg Ungerer, Michal Hocko, Mike Rapoport, linux-m68k, LKML, kernel-janitors Hi Markus, On Sat, Jul 6, 2019 at 1:57 AM Finn Thain <fthain@telegraphics.com.au> wrote: > On Fri, 5 Jul 2019, Markus Elfring wrote: > > From: Markus Elfring <elfring@users.sourceforge.net> > > Date: Fri, 5 Jul 2019 17:11:37 +0200 > > > > Avoid an extra function call > > by using a ternary operator instead of a conditional statement for a > > setting selection. Have you looked at the actual assembler output generated by the compiler? > > This issue was detected by using the Coccinelle software. > > > > Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> > > --- > > arch/m68k/mm/mcfmmu.c | 10 ++++------ > > 1 file changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c > > index 6cb1e41d58d0..02fc0778028e 100644 > > --- a/arch/m68k/mm/mcfmmu.c > > +++ b/arch/m68k/mm/mcfmmu.c > > @@ -146,12 +146,10 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) > > > > mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | > > ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); > > - > > - if (dtlb) > > - mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); > > - else > > - mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); > > - > > + mmu_write(MMUOR, > > + dtlb > > + ? MMUOR_ACC | MMUOR_UAA > > + : MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); While the ternary operator can be useful for short expressions, it can also lead to hard-to-read code. IMHO the latter is the case here (hint: the expression needs 3 lines). > If you are trying to avoid redundancy, why not finish the job? > > + mmu_write(MMUOR, (dtlb ? 0 : MMUOR_ITLB) | MMUOR_ACC | MMUOR_UAA); Thanks Finn, much better! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: m68k: One function call less in cf_tlb_miss() 2019-07-14 13:23 ` Geert Uytterhoeven @ 2019-07-14 16:05 ` Markus Elfring 2019-07-14 21:14 ` Geert Uytterhoeven 0 siblings, 1 reply; 6+ messages in thread From: Markus Elfring @ 2019-07-14 16:05 UTC (permalink / raw) To: Geert Uytterhoeven, linux-m68k, kernel-janitors Cc: Finn Thain, Andrew Morton, Greg Ungerer, Michal Hocko, Mike Rapoport, LKML >>> Avoid an extra function call by using a ternary operator >>> instead of a conditional statement for a setting selection. > > Have you looked at the actual assembler output generated by the compiler? Not yet. * Can the suggested small refactoring matter for a specific software combination there? * Would you like to clarify this change possibility a bit more? Regards, Markus ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: m68k: One function call less in cf_tlb_miss() 2019-07-14 16:05 ` Markus Elfring @ 2019-07-14 21:14 ` Geert Uytterhoeven 2019-07-15 6:11 ` Markus Elfring 0 siblings, 1 reply; 6+ messages in thread From: Geert Uytterhoeven @ 2019-07-14 21:14 UTC (permalink / raw) To: Markus Elfring Cc: linux-m68k, kernel-janitors, Finn Thain, Andrew Morton, Greg Ungerer, Michal Hocko, Mike Rapoport, LKML Hi Markus, On Sun, Jul 14, 2019 at 6:06 PM Markus Elfring <Markus.Elfring@web.de> wrote: > >>> Avoid an extra function call by using a ternary operator > >>> instead of a conditional statement for a setting selection. > > > > Have you looked at the actual assembler output generated by the compiler? > > Not yet. You better do, it can be a good learning experience! > * Can the suggested small refactoring matter for a specific software combination there? > * Would you like to clarify this change possibility a bit more? -EPARSE No need to relay my emails through https://en.wikipedia.org/wiki/ELIZA ;-) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: m68k: One function call less in cf_tlb_miss() 2019-07-14 21:14 ` Geert Uytterhoeven @ 2019-07-15 6:11 ` Markus Elfring 0 siblings, 0 replies; 6+ messages in thread From: Markus Elfring @ 2019-07-15 6:11 UTC (permalink / raw) To: Geert Uytterhoeven, linux-m68k, kernel-janitors Cc: Finn Thain, Andrew Morton, Greg Ungerer, Michal Hocko, Mike Rapoport, LKML > You better do, It can eventually happen again under other circumstances. > it can be a good learning experience! This can be also possible. >> * Can the suggested small refactoring matter for a specific software combination there? >> * Would you like to clarify this change possibility a bit more? > > -EPARSE I am curious where you got parsing (or more understanding) difficulties for these questions. Regards, Markus ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-07-15 6:11 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-07-05 15:18 [PATCH] m68k: One function call less in cf_tlb_miss() Markus Elfring 2019-07-05 23:56 ` Finn Thain 2019-07-14 13:23 ` Geert Uytterhoeven 2019-07-14 16:05 ` Markus Elfring 2019-07-14 21:14 ` Geert Uytterhoeven 2019-07-15 6:11 ` Markus Elfring
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