Messages in this thread | | | Date | Wed, 9 Jan 2019 10:56:52 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v7] mm/page_alloc.c: memory_hotplug: free pages as higher order |
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On Wed, 09 Jan 2019 16:36:36 +0530 Arun KS <arunks@codeaurora.org> wrote:
> On 2019-01-09 16:27, Michal Hocko wrote: > > On Wed 09-01-19 16:12:48, Arun KS wrote: > > [...] > >> It will be called once per online of a section and the arg value is > >> always > >> set to 0 while entering online_pages_range. > > > > You rare right that this will be the case in the most simple scenario. > > But the point is that the callback can be called several times from > > walk_system_ram_range and then your current code wouldn't work > > properly. > > Thanks. Will use +=
The v8 patch https://lore.kernel.org/lkml/1547032395-24582-1-git-send-email-arunks@codeaurora.org/T/#u
(which you apparently sent 7 minutes after typing the above) still has
static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { - unsigned long i; unsigned long onlined_pages = *(unsigned long *)arg; - struct page *page; if (PageReserved(pfn_to_page(start_pfn))) - for (i = 0; i < nr_pages; i++) { - page = pfn_to_page(start_pfn + i); - (*online_page_callback)(page); - onlined_pages++; - } + onlined_pages = online_pages_blocks(start_pfn, nr_pages);
Even then the code makes no sense.
static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { unsigned long onlined_pages = *(unsigned long *)arg;
if (PageReserved(pfn_to_page(start_pfn))) onlined_pages += online_pages_blocks(start_pfn, nr_pages);
online_mem_sections(start_pfn, start_pfn + nr_pages);
*(unsigned long *)arg += onlined_pages; return 0; }
Either the final assignment should be
*(unsigned long *)arg = onlined_pages;
or the initialization should be
unsigned long onlined_pages = 0;
This is becoming a tad tiresome and I'd prefer not to have to check up on such things. Can we please get this right?
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