Messages in this thread | | | Subject | Re: [PATCH] async: Let kfree() out of the critical area of the lock | From | Yunfeng Ye <> | Date | Thu, 26 Sep 2019 15:58:36 +0800 |
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On 2019/9/25 23:20, Alexander Duyck wrote: > On Wed, 2019-09-25 at 20:52 +0800, Yunfeng Ye wrote: >> It's not necessary to put kfree() in the critical area of the lock, so >> let it out. >> >> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> >> --- >> kernel/async.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/async.c b/kernel/async.c >> index 4f9c1d6..1de270d 100644 >> --- a/kernel/async.c >> +++ b/kernel/async.c >> @@ -135,12 +135,12 @@ static void async_run_entry_fn(struct work_struct *work) >> list_del_init(&entry->domain_list); >> list_del_init(&entry->global_list); >> >> - /* 3) free the entry */ >> - kfree(entry); >> atomic_dec(&entry_count); >> - >> spin_unlock_irqrestore(&async_lock, flags); >> >> + /* 3) free the entry */ >> + kfree(entry); >> + >> /* 4) wake up any waiters */ >> wake_up(&async_done); >> } > > It probably wouldn't hurt to update the patch description to mention that > async_schedule_node_domain does the allocation outside of the lock, then > takes the lock and does the list addition and entry_count increment inside > the critical section so this is just updating the code to match that it > seems. > > Otherwise the change itself looks safe to me, though I am not sure there > is a performance gain to be had so this is mostly just a cosmetic patch. > The async_lock is big global lock, I think it's good to put kfree() outside to keep the critical area as short as possible.
thanks.
> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> > > > . >
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