On Mon, Jun 22, 2020 at 09:33:28AM +0200, David Hildenbrand wrote: >On 20.06.20 03:49, Dan Williams wrote: >> On Fri, Jun 19, 2020 at 5:59 AM David Hildenbrand <da...@redhat.com> wrote: >>> >>> Commit e900a918b098 ("mm: shuffle initial free memory to improve >>> memory-side-cache utilization") promised "autodetection of a >>> memory-side-cache (to be added in a follow-on patch)" over a year ago. >>> >>> The original series included patches [1], however, they were dropped >>> during review [2] to be followed-up later. >>> >>> Due to lack of platforms that publish an HMAT, autodetection is currently >>> not implemented. However, manual activation is actively used [3]. Let's >>> simplify for now and re-add when really (ever?) needed. >>> >>> [1] >>> https://lkml.kernel.org/r/154510700291.1941238.817190985966612531.st...@dwillia2-desk3.amr.corp.intel.com >>> [2] >>> https://lkml.kernel.org/r/154690326478.676627.103843791978176914.st...@dwillia2-desk3.amr.corp.intel.com >>> [3] >>> https://lkml.kernel.org/r/CAPcyv4irwGUU2x+c6b4L=kbb1dnasnkaazd6ospyjl9kfsn...@mail.gmail.com >>> >>> Cc: Andrew Morton <a...@linux-foundation.org> >>> Cc: Johannes Weiner <han...@cmpxchg.org> >>> Cc: Michal Hocko <mho...@suse.com> >>> Cc: Minchan Kim <minc...@kernel.org> >>> Cc: Huang Ying <ying.hu...@intel.com> >>> Cc: Wei Yang <richard.weiy...@gmail.com> >>> Cc: Mel Gorman <mgor...@techsingularity.net> >>> Cc: Dan Williams <dan.j.willi...@intel.com> >>> Signed-off-by: David Hildenbrand <da...@redhat.com> >>> --- >>> mm/shuffle.c | 28 ++-------------------------- >>> mm/shuffle.h | 17 ----------------- >>> 2 files changed, 2 insertions(+), 43 deletions(-) >>> >>> diff --git a/mm/shuffle.c b/mm/shuffle.c >>> index dd13ab851b3ee..9b5cd4b004b0f 100644 >>> --- a/mm/shuffle.c >>> +++ b/mm/shuffle.c >>> @@ -10,33 +10,11 @@ >>> #include "shuffle.h" >>> >>> DEFINE_STATIC_KEY_FALSE(page_alloc_shuffle_key); >>> -static unsigned long shuffle_state __ro_after_init; >>> - >>> -/* >>> - * Depending on the architecture, module parameter parsing may run >>> - * before, or after the cache detection. SHUFFLE_FORCE_DISABLE prevents, >>> - * or reverts the enabling of the shuffle implementation. SHUFFLE_ENABLE >>> - * attempts to turn on the implementation, but aborts if it finds >>> - * SHUFFLE_FORCE_DISABLE already set. >>> - */ >>> -__meminit void page_alloc_shuffle(enum mm_shuffle_ctl ctl) >>> -{ >>> - if (ctl == SHUFFLE_FORCE_DISABLE) >>> - set_bit(SHUFFLE_FORCE_DISABLE, &shuffle_state); >>> - >>> - if (test_bit(SHUFFLE_FORCE_DISABLE, &shuffle_state)) { >>> - if (test_and_clear_bit(SHUFFLE_ENABLE, &shuffle_state)) >>> - static_branch_disable(&page_alloc_shuffle_key); >>> - } else if (ctl == SHUFFLE_ENABLE >>> - && !test_and_set_bit(SHUFFLE_ENABLE, >>> &shuffle_state)) >>> - static_branch_enable(&page_alloc_shuffle_key); >>> -} >>> >>> static bool shuffle_param; >>> static int shuffle_show(char *buffer, const struct kernel_param *kp) >>> { >>> - return sprintf(buffer, "%c\n", test_bit(SHUFFLE_ENABLE, >>> &shuffle_state) >>> - ? 'Y' : 'N'); >>> + return sprintf(buffer, "%c\n", shuffle_param ? 'Y' : 'N'); >>> } >>> >>> static __meminit int shuffle_store(const char *val, >>> @@ -47,9 +25,7 @@ static __meminit int shuffle_store(const char *val, >>> if (rc < 0) >>> return rc; >>> if (shuffle_param) >>> - page_alloc_shuffle(SHUFFLE_ENABLE); >>> - else >>> - page_alloc_shuffle(SHUFFLE_FORCE_DISABLE); >>> + static_branch_enable(&page_alloc_shuffle_key); >>> return 0; >>> } >> >> Let's do proper input validation here and require 1 / 'true' to enable >> shuffling and not also allow 0 to be an 'enable' value. > >I don't think that's currently done? > >param_set_bool(val, kp) will only default val==NULL to 'true'. Passing 0 >will properly be handled by strtobool(). Or am I missing something? >
Agree with this statement. >Thanks! > >-- >Thanks, > >David / dhildenb -- Wei Yang Help you, Help me