Re: [RFC PATCH] mm/hugetlb: Avoid soft lockup in set_max_huge_pages()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 7/26/16 11:58 PM, Dave Hansen wrote:
On 07/26/2016 08:44 AM, Jia He wrote:
This patch is to fix such soft lockup. I thouhgt it is safe to call
cond_resched() because alloc_fresh_gigantic_page and alloc_fresh_huge_page
are out of spin_lock/unlock section.
Yikes.  So the call site for both the things you patch is this:

         while (count > persistent_huge_pages(h)) {
...
                 spin_unlock(&hugetlb_lock);
                 if (hstate_is_gigantic(h))
                         ret = alloc_fresh_gigantic_page(h, nodes_allowed);
                 else
                         ret = alloc_fresh_huge_page(h, nodes_allowed);
                 spin_lock(&hugetlb_lock);
and you choose to patch both of the alloc_*() functions.  Why not just
fix it at the common call site?  Seems like that
spin_lock(&hugetlb_lock) could be a cond_resched_lock() which would fix
both cases.

Also, putting that cond_resched() inside the for_each_node*() loop is an
odd choice.  It seems to indicate that the loops can take a long time,
which really isn't the case.  The _loop_ isn't long, right?
Yes,thanks for the suggestions
Will send out V2 later

B.R.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]