| Message ID | 20211025230503.2650970-3-naoya.horiguchi@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/hwpoison: fix unpoison_memory() | expand |
On Mon, Oct 25, 2021 at 4:06 PM Naoya Horiguchi <naoya.horiguchi@linux.dev> wrote: > > From: Naoya Horiguchi <naoya.horiguchi@nec.com> > > Now memory_failure() and unpoison_memory() are protected by mf_mutex, > so no need to explicitly check races between them. So remove them. It seems this patch could be folded into patch #1. Some "unlock_mutex" were added by patch #1 then they were removed by this patch immediately, it seems a bit of a waste and this patch is actually the by-product of patch #1. > > Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> > --- > mm/memory-failure.c | 37 ------------------------------------- > 1 file changed, 37 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 97297edfbd8e..a47b741ca04b 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1507,14 +1507,6 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) > lock_page(head); > page_flags = head->flags; > > - if (!PageHWPoison(head)) { > - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); > - num_poisoned_pages_dec(); > - unlock_page(head); > - put_page(head); > - return 0; > - } > - > /* > * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so > * simply disable it. In order to make it work properly, we need > @@ -1789,16 +1781,6 @@ int memory_failure(unsigned long pfn, int flags) > */ > page_flags = p->flags; > > - /* > - * unpoison always clear PG_hwpoison inside page lock > - */ > - if (!PageHWPoison(p)) { > - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); > - num_poisoned_pages_dec(); > - unlock_page(p); > - put_page(p); > - goto unlock_mutex; > - } > if (hwpoison_filter(p)) { > if (TestClearPageHWPoison(p)) > num_poisoned_pages_dec(); > @@ -2016,17 +1998,6 @@ int unpoison_memory(unsigned long pfn) > goto unlock_mutex; > } > > - /* > - * unpoison_memory() can encounter thp only when the thp is being > - * worked by memory_failure() and the page lock is not held yet. > - * In such case, we yield to memory_failure() and make unpoison fail. > - */ > - if (!PageHuge(page) && PageTransHuge(page)) { > - unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", > - pfn, &unpoison_rs); > - goto unlock_mutex; > - } > - > if (!get_hwpoison_page(p, flags)) { > if (TestClearPageHWPoison(p)) > num_poisoned_pages_dec(); > @@ -2035,20 +2006,12 @@ int unpoison_memory(unsigned long pfn) > goto unlock_mutex; > } > > - lock_page(page); > - /* > - * This test is racy because PG_hwpoison is set outside of page lock. > - * That's acceptable because that won't trigger kernel panic. Instead, > - * the PG_hwpoison page will be caught and isolated on the entrance to > - * the free buddy page pool. > - */ > if (TestClearPageHWPoison(page)) { > unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", > pfn, &unpoison_rs); > num_poisoned_pages_dec(); > freeit = 1; > } > - unlock_page(page); > > put_page(page); > if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) > -- > 2.25.1 >
On Tue, Oct 26, 2021 at 06:04:13PM -0700, Yang Shi wrote: > On Mon, Oct 25, 2021 at 4:06 PM Naoya Horiguchi > <naoya.horiguchi@linux.dev> wrote: > > > > From: Naoya Horiguchi <naoya.horiguchi@nec.com> > > > > Now memory_failure() and unpoison_memory() are protected by mf_mutex, > > so no need to explicitly check races between them. So remove them. > > It seems this patch could be folded into patch #1. Some "unlock_mutex" > were added by patch #1 then they were removed by this patch > immediately, it seems a bit of a waste and this patch is actually the > by-product of patch #1. OK, I'll do this in the next post. Thanks, Naoya Horiguchi
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 97297edfbd8e..a47b741ca04b 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1507,14 +1507,6 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) lock_page(head); page_flags = head->flags; - if (!PageHWPoison(head)) { - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); - num_poisoned_pages_dec(); - unlock_page(head); - put_page(head); - return 0; - } - /* * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so * simply disable it. In order to make it work properly, we need @@ -1789,16 +1781,6 @@ int memory_failure(unsigned long pfn, int flags) */ page_flags = p->flags; - /* - * unpoison always clear PG_hwpoison inside page lock - */ - if (!PageHWPoison(p)) { - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); - num_poisoned_pages_dec(); - unlock_page(p); - put_page(p); - goto unlock_mutex; - } if (hwpoison_filter(p)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); @@ -2016,17 +1998,6 @@ int unpoison_memory(unsigned long pfn) goto unlock_mutex; } - /* - * unpoison_memory() can encounter thp only when the thp is being - * worked by memory_failure() and the page lock is not held yet. - * In such case, we yield to memory_failure() and make unpoison fail. - */ - if (!PageHuge(page) && PageTransHuge(page)) { - unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", - pfn, &unpoison_rs); - goto unlock_mutex; - } - if (!get_hwpoison_page(p, flags)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); @@ -2035,20 +2006,12 @@ int unpoison_memory(unsigned long pfn) goto unlock_mutex; } - lock_page(page); - /* - * This test is racy because PG_hwpoison is set outside of page lock. - * That's acceptable because that won't trigger kernel panic. Instead, - * the PG_hwpoison page will be caught and isolated on the entrance to - * the free buddy page pool. - */ if (TestClearPageHWPoison(page)) { unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", pfn, &unpoison_rs); num_poisoned_pages_dec(); freeit = 1; } - unlock_page(page); put_page(page); if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))