| Message ID | 20210805190253.2795604-9-zi.yan@sent.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Make MAX_ORDER adjustable as a kernel boot time parameter. | expand |
On Thu, Aug 05, 2021 at 03:02:46PM -0400, Zi Yan wrote: > From: Zi Yan <ziy@nvidia.com> > > It keeps the existing behavior after MAX_ORDER is increased beyond > a section size. > > Signed-off-by: Zi Yan <ziy@nvidia.com> > Cc: Mike Rapoport <rppt@kernel.org> > Cc: David Hildenbrand <david@redhat.com> > Cc: Oscar Salvador <osalvador@suse.de> > Cc: Ying Chen <chenying.kernel@bytedance.com> > Cc: Feng Zhou <zhoufeng.zf@bytedance.com> > Cc: linux-fsdevel@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > fs/proc/kcore.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c > index 3f148759a5fd..77b7ba48fb44 100644 > --- a/fs/proc/kcore.c > +++ b/fs/proc/kcore.c > @@ -486,7 +486,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) > } > } > > - if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) { > + if (page_offline_frozen++ % PAGES_PER_SECTION == 0) { The behavior changes here. E.g. with default configuration on x86 instead of cond_resched() every 2M we get cond_resched() every 128M. I'm not saying it's wrong but at least it deserves an explanation why. > page_offline_thaw(); > cond_resched(); > page_offline_freeze(); > -- > 2.30.2 >
On 7 Aug 2021, at 6:32, Mike Rapoport wrote: > On Thu, Aug 05, 2021 at 03:02:46PM -0400, Zi Yan wrote: >> From: Zi Yan <ziy@nvidia.com> >> >> It keeps the existing behavior after MAX_ORDER is increased beyond >> a section size. >> >> Signed-off-by: Zi Yan <ziy@nvidia.com> >> Cc: Mike Rapoport <rppt@kernel.org> >> Cc: David Hildenbrand <david@redhat.com> >> Cc: Oscar Salvador <osalvador@suse.de> >> Cc: Ying Chen <chenying.kernel@bytedance.com> >> Cc: Feng Zhou <zhoufeng.zf@bytedance.com> >> Cc: linux-fsdevel@vger.kernel.org >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> --- >> fs/proc/kcore.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c >> index 3f148759a5fd..77b7ba48fb44 100644 >> --- a/fs/proc/kcore.c >> +++ b/fs/proc/kcore.c >> @@ -486,7 +486,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) >> } >> } >> >> - if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) { >> + if (page_offline_frozen++ % PAGES_PER_SECTION == 0) { > > The behavior changes here. E.g. with default configuration on x86 instead > of cond_resched() every 2M we get cond_resched() every 128M. > > I'm not saying it's wrong but at least it deserves an explanation why. Sure. I will also think about whether I should use PAGES_PER_SECTION or pageblock_nr_pages to replace MAX_ORDER in this and other patches. pageblock_nr_pages will be unchanged, so at least in x86_64, using pageblock_nr_pages would not change code behaviors. — Best Regards, Yan, Zi
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 3f148759a5fd..77b7ba48fb44 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -486,7 +486,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) } } - if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) { + if (page_offline_frozen++ % PAGES_PER_SECTION == 0) { page_offline_thaw(); cond_resched(); page_offline_freeze();