* [PATCH 4/4] mm,hugetlb: compute page_size_log properly [not found] <1486673582-6979-1-git-send-email-dave@stgolabs.net> @ 2017-02-09 20:53 ` Davidlohr Bueso 2017-02-10 10:20 ` Michal Hocko 0 siblings, 1 reply; 6+ messages in thread From: Davidlohr Bueso @ 2017-02-09 20:53 UTC (permalink / raw) To: akpm; +Cc: manfred, dave, linux-kernel, linux-mm, Davidlohr Bueso The SHM_HUGE_* stuff was introduced in: 42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB) It unnecessarily adds another layer, specific to sysv shm, without anything special about it: the macros are identical to the MAP_HUGE_* stuff, which in turn does correctly describe the hugepage subsystem. One example of the problems with extra layers what this patch fixes: mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously harmless but it would still be grand to get rid of it -- although now in the manpages I don't see that happening. Cc: linux-mm@kvack.org Signed-off-by: Davidlohr Bueso <dbueso@suse.de> --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index 499b988b1639..40b29aca18c1 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1479,7 +1479,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, struct user_struct *user = NULL; struct hstate *hs; - hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK); + hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); if (!hs) return -EINVAL; -- 2.6.6 -- 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> ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly 2017-02-09 20:53 ` [PATCH 4/4] mm,hugetlb: compute page_size_log properly Davidlohr Bueso @ 2017-02-10 10:20 ` Michal Hocko 2017-02-10 16:51 ` Davidlohr Bueso 0 siblings, 1 reply; 6+ messages in thread From: Michal Hocko @ 2017-02-10 10:20 UTC (permalink / raw) To: Davidlohr Bueso; +Cc: akpm, manfred, linux-kernel, linux-mm, Davidlohr Bueso On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote: > The SHM_HUGE_* stuff was introduced in: > > 42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB) > > It unnecessarily adds another layer, specific to sysv shm, without > anything special about it: the macros are identical to the MAP_HUGE_* > stuff, which in turn does correctly describe the hugepage subsystem. > > One example of the problems with extra layers what this patch fixes: > mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously > harmless but it would still be grand to get rid of it -- although > now in the manpages I don't see that happening. Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi headers AFAICS. > > Cc: linux-mm@kvack.org > Signed-off-by: Davidlohr Bueso <dbueso@suse.de> > --- > mm/mmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index 499b988b1639..40b29aca18c1 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1479,7 +1479,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, > struct user_struct *user = NULL; > struct hstate *hs; > > - hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK); > + hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); > if (!hs) > return -EINVAL; > > -- > 2.6.6 > > -- > 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> -- Michal Hocko SUSE Labs -- 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> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly 2017-02-10 10:20 ` Michal Hocko @ 2017-02-10 16:51 ` Davidlohr Bueso 2017-02-20 16:11 ` Michal Hocko 0 siblings, 1 reply; 6+ messages in thread From: Davidlohr Bueso @ 2017-02-10 16:51 UTC (permalink / raw) To: Michal Hocko; +Cc: akpm, manfred, linux-kernel, linux-mm, Davidlohr Bueso On Fri, 10 Feb 2017, Michal Hocko wrote: >On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote: >> The SHM_HUGE_* stuff was introduced in: >> >> 42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB) >> >> It unnecessarily adds another layer, specific to sysv shm, without >> anything special about it: the macros are identical to the MAP_HUGE_* >> stuff, which in turn does correctly describe the hugepage subsystem. >> >> One example of the problems with extra layers what this patch fixes: >> mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously >> harmless but it would still be grand to get rid of it -- although >> now in the manpages I don't see that happening. > >Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi >headers AFAICS. Yeah that was my original idea, however I noticed that shmget.2 mentions kernel internals as part of SHM_HUGE_{2MB,1GB}, ie: SHM_HUGE_SHIFT. So dropping _MASK doesn't make sense if we are going to keep _SHIFT. Thanks, Davidlohr -- 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> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly 2017-02-10 16:51 ` Davidlohr Bueso @ 2017-02-20 16:11 ` Michal Hocko 2017-02-22 16:03 ` Davidlohr Bueso 0 siblings, 1 reply; 6+ messages in thread From: Michal Hocko @ 2017-02-20 16:11 UTC (permalink / raw) To: Davidlohr Bueso; +Cc: akpm, manfred, linux-kernel, linux-mm, Davidlohr Bueso Sorry for a late reply, I wasn't online last week On Fri 10-02-17 08:51:11, Davidlohr Bueso wrote: > On Fri, 10 Feb 2017, Michal Hocko wrote: > > > On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote: > > > The SHM_HUGE_* stuff was introduced in: > > > > > > 42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB) > > > > > > It unnecessarily adds another layer, specific to sysv shm, without > > > anything special about it: the macros are identical to the MAP_HUGE_* > > > stuff, which in turn does correctly describe the hugepage subsystem. > > > > > > One example of the problems with extra layers what this patch fixes: > > > mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously > > > harmless but it would still be grand to get rid of it -- although > > > now in the manpages I don't see that happening. > > > > Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi > > headers AFAICS. > > Yeah that was my original idea, however I noticed that shmget.2 mentions > kernel internals as part of SHM_HUGE_{2MB,1GB}, ie: SHM_HUGE_SHIFT. So > dropping _MASK doesn't make sense if we are going to keep _SHIFT. I am not sure I understand. $ git grep SHM_HUGE_ include/uapi/ $ So there doesn't seem to be any user visible constant. The man page mentiones is but I do not really see how is the userspace supposed to use it. -- Michal Hocko SUSE Labs -- 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> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly 2017-02-20 16:11 ` Michal Hocko @ 2017-02-22 16:03 ` Davidlohr Bueso 2017-02-22 16:11 ` Michal Hocko 0 siblings, 1 reply; 6+ messages in thread From: Davidlohr Bueso @ 2017-02-22 16:03 UTC (permalink / raw) To: Michal Hocko; +Cc: akpm, manfred, linux-kernel, linux-mm, Davidlohr Bueso On Mon, 20 Feb 2017, Michal Hocko wrote: >I am not sure I understand. >$ git grep SHM_HUGE_ include/uapi/ >$ > >So there doesn't seem to be any user visible constant. The man page >mentiones is but I do not really see how is the userspace supposed to >use it. Yeah, userspace is not supposed to use it, it's just there because the manpage describes kernel internals. I'm not really a big fan of touching manpages (and ipc is already full of corner cases), but I guess nobody can really complain if we rip out all the SHM_HUGE_ stuff. Thanks, Davidlohr -- 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> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly 2017-02-22 16:03 ` Davidlohr Bueso @ 2017-02-22 16:11 ` Michal Hocko 0 siblings, 0 replies; 6+ messages in thread From: Michal Hocko @ 2017-02-22 16:11 UTC (permalink / raw) To: Davidlohr Bueso; +Cc: akpm, manfred, linux-kernel, linux-mm, Davidlohr Bueso On Wed 22-02-17 08:03:19, Davidlohr Bueso wrote: > On Mon, 20 Feb 2017, Michal Hocko wrote: > > > I am not sure I understand. > > $ git grep SHM_HUGE_ include/uapi/ > > $ > > > > So there doesn't seem to be any user visible constant. The man page > > mentiones is but I do not really see how is the userspace supposed to > > use it. > > Yeah, userspace is not supposed to use it, it's just there because > the manpage describes kernel internals. Which is wrong! > I'm not really a big fan > of touching manpages (and ipc is already full of corner cases), > but I guess nobody can really complain if we rip out all the > SHM_HUGE_ stuff. yeah, let's just get rid of it. -- Michal Hocko SUSE Labs -- 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> ^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <1486673582-6979-1-git-send-email-dave@stgolabs.net>
2017-02-09 20:53 ` [PATCH 4/4] mm,hugetlb: compute page_size_log properly Davidlohr Bueso
2017-02-10 10:20 ` Michal Hocko
2017-02-10 16:51 ` Davidlohr Bueso
2017-02-20 16:11 ` Michal Hocko
2017-02-22 16:03 ` Davidlohr Bueso
2017-02-22 16:11 ` Michal Hocko
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