| Message ID | 20241014105912.3207374-16-ryan.roberts@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Boot-time page size selection for arm64 | expand |
+ Arnaldo Carvalho de Melo, Ingo Molnar, Namhyung Kim, Peter Zijlstra This was a rather tricky series to get the recipients correct for and my script did not realize that "supporter" was a pseudonym for "maintainer" so you were missed off the original post. Appologies! More context in cover letter: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ On 14/10/2024 11:58, Ryan Roberts wrote: > To prepare for supporting boot-time page size selection, refactor code > to remove assumptions about PAGE_SIZE being compile-time constant. Code > intended to be equivalent when compile-time page size is active. > > Refactor a BUILD_BUG_ON() so that we test against the limit; _format is > invariant to page size so testing it is no bigger than the minimum > supported size is sufficient. > > Wrap global variables that are initialized with PAGE_SIZE derived values > using DEFINE_GLOBAL_PAGE_SIZE_VAR() so their initialization can be > deferred for boot-time page size builds. > > Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> > --- > > ***NOTE*** > Any confused maintainers may want to read the cover note here for context: > https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ > > include/linux/perf_event.h | 2 +- > kernel/events/core.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 1a8942277ddad..b7972155f93eb 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -1872,7 +1872,7 @@ _name##_show(struct device *dev, \ > struct device_attribute *attr, \ > char *page) \ > { \ > - BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE); \ > + BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE_MIN); \ > return sprintf(page, _format "\n"); \ > } \ > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 8a6c6bbcd658a..81149663ab7d8 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -419,7 +419,7 @@ static struct kmem_cache *perf_event_cache; > int sysctl_perf_event_paranoid __read_mostly = 2; > > /* Minimum for 512 kiB + 1 user control page */ > -int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ > +__DEFINE_GLOBAL_PAGE_SIZE_VAR(int, sysctl_perf_event_mlock, __read_mostly, 512 + (PAGE_SIZE / 1024)); /* 'free' kiB per user */ > > /* > * max perf event sample rate
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 1a8942277ddad..b7972155f93eb 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1872,7 +1872,7 @@ _name##_show(struct device *dev, \ struct device_attribute *attr, \ char *page) \ { \ - BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE); \ + BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE_MIN); \ return sprintf(page, _format "\n"); \ } \ diff --git a/kernel/events/core.c b/kernel/events/core.c index 8a6c6bbcd658a..81149663ab7d8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -419,7 +419,7 @@ static struct kmem_cache *perf_event_cache; int sysctl_perf_event_paranoid __read_mostly = 2; /* Minimum for 512 kiB + 1 user control page */ -int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ +__DEFINE_GLOBAL_PAGE_SIZE_VAR(int, sysctl_perf_event_mlock, __read_mostly, 512 + (PAGE_SIZE / 1024)); /* 'free' kiB per user */ /* * max perf event sample rate
To prepare for supporting boot-time page size selection, refactor code to remove assumptions about PAGE_SIZE being compile-time constant. Code intended to be equivalent when compile-time page size is active. Refactor a BUILD_BUG_ON() so that we test against the limit; _format is invariant to page size so testing it is no bigger than the minimum supported size is sufficient. Wrap global variables that are initialized with PAGE_SIZE derived values using DEFINE_GLOBAL_PAGE_SIZE_VAR() so their initialization can be deferred for boot-time page size builds. Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> --- ***NOTE*** Any confused maintainers may want to read the cover note here for context: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ include/linux/perf_event.h | 2 +- kernel/events/core.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)