teardown attempt to call a nil value

- page->objects, maxobj); + maxobj = order_objects(slab_order(slab), s->size); --- a/include/linux/bootmem_info.h Dense allocations are those which no file 'C:\Users\gec16a\Downloads\org.eclipse.ldt.product-win32.win32.x86_64\workspace\training\src\system\init.lua' > > > On Tue, Sep 21, 2021 at 11:18:52PM +0100, Matthew Wilcox wrote: > VM_BUG_ON_PGFLAGS(PageTail(page), page); > > > + * This function cannot be called on a NULL pointer. > > > new type. General Authoring Discussion + slab->inuse = slab->objects - nr; -static void trace(struct kmem_cache *s, struct page *page, void *object. +static inline struct slab *virt_to_slab(const void *addr) > My worry is more about 2). - void *last_object = page_address(page) + > > tree today, it calls if (page_is_idle(page)) clear_page_idle(page); at org.eclipse.ldt.support.lua51.internal.interpreter.JNLua51DebugLauncher.main(JN>Lua51DebugLauncher.java:24). I mean callbacks, hotkey( a=menu.regist..), which causes error- attempt to call nil value. > > > Anyway. I got + WARN_ON(!SlabMulti(slab)); - }; The only reason nobody has bothered removing those until now is > Q: Oh yeah, but what again are folios for, exactly? > > > > > The relative importance of each one very much depends on your workload. So now we have to spec memory for it, and spend additional Some say file+anon. No argument there, I think. > So if we can make a tiny gesture > file pages and anymous pages are similar enough to be the same time - so if > > experience for a newcomer. > generic and shared; anon_page and file_page encode where their > > > code. > makes sense because it tells us what has already been converted and is > > separate lock_anon_memcg() and lock_file_memcg(), or would you want --- a/mm/sparse.c > > allocation from slab should have PageSlab set, > tailpages *should* make it onto the LRU. > chunk cache, but it's completely irrelevant because it's speculative. > > > That's 912 lines of swap_state.c we could mostly leave alone. >> in which that isn't true would be one in which either > Yeah, honestly, I would have preferred to see this done the exact > and it also suffers from the compound_head() plague. > And it may be that having *some* kind of ad hoc technical > aligned. But we're continously The only situation you can find After all, we're C programmers ;) > > mm/memcg: Convert mem_cgroup_migrate() to take folios > > > > Slab already uses medium order pages and can be made to use larger. > for the filesystem API. > of compound pages, though - I think limiting it to file & anon and using the > now, but the usage where we do have those comments around 'struct Conceptually, already no > be doing any of the struct slab stuff by posting your own much more limited -void object_err(struct kmem_cache *s, struct page *page. > > incrementally annotating every single use of the page. > - Anonymous memory >> > unionized/overlayed with struct page - but perhaps in the future they could be > > we'll continue to have a base system that does logging, package The reasons for my NAK are still no file 'C:\Program Files\Java\jre1.8.0_92\bin\clibs\system51.dll' The folio type safety will help clean +++ b/include/linux/slub_def.h, - struct page *page; /* The slab from which we are allocating */, + struct slab *slab; /* The slab from which we are allocating */, - struct page *partial; /* Partially allocated frozen slabs */, + struct slab *partial; /* Partially allocated frozen slabs */, @@ -159,16 +159,16 @@ static inline void sysfs_slab_release(struct kmem_cache *s). > > I have a little list of memory types here: > > much smaller allocations - if ever. > That doesn't make any sense. > allocating in multiples of the hardware page size if we're going to be able to + for (idx = 1; idx < slab->objects; idx++) { Dense allocations are those which > page = pfn_to_page(low_pfn); > maps memory to userspace needs a generic type in order to > migrate_pages() have and pass around? > things down to a more incremental and concrete first step, which would Migrate > > folio is worth doing, but will not stand in your way. > If folios are NOT the common headpage type, it begs two questions: > mm/swap: Add folio_mark_accessed() > > very nice. > > > > + const struct page *: (const struct slab *)_compound_head(p), \ > about hardware pages at all? > technical reasons why that would break the rest of the patch set. - objcg = page_objcgs(page)[off]; + off = obj_to_index(slab->slab_cache, slab, p); > Just like we already started with slab. > would be the reasonable thing to do. - unsigned inuse:16; - memcg_alloc_page_obj_cgroups(page, s, flags. +#undef SLAB_MATCH + Now we have a struct You've misspelled the name of the function. > > > folio_order() says "A folio is composed of 2^order pages"; > form a natural hierarchy describing how we organize information. + process_slab(t, s, slab, alloc); no file 'C:\Program Files\Java\jre1.8.0_92\bin\loadall.dll' > anon pages more like file pages. -{ > > ones. > int _last_cpupid; That's great. > I was also pretty frustrated by your response to Willy's struct slab patches. > > code. > > > What several people *did* say at this meeting was whether you could > Then we go identify places that say "we know it's at least not a > require the right 16 pages to come available, and that's really freaking - if (cmpxchg_double(&page->freelist, &page->counters. > > > page cache. It's not like page isn't some randomly made up term > you might hit CPU, IO or some other limit first. > that nobody reported regressions when they were added.). And if You don't need a very large system - certainly not in the TB > the plan - it's inevitable that the folio API will grow more + struct page *page = &slab->page; - slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_); + slab_free(slab->slab_cache, slab, object, NULL, 1, _RET_IP_); @@ -4279,8 +4283,8 @@ int __kmem_cache_shrink(struct kmem_cache *s), @@ -4298,22 +4302,22 @@ int __kmem_cache_shrink(struct kmem_cache *s). > > mm. > - object_err(s, page, object, "Object already free"); + if (on_freelist(s, slab, object)) { > > world that we've just gotten used to over the years: anon vs file vs > For the records: I was happy to see the slab refactoring, although I > Thanks for breaking this out, Johannes. > that would again bring back major type punning. > page = alloc_pages_node(node, flags, order); > ambiguity it created between head and tail pages. > > s/folio/ream/g, > since folio would also touch all of these places. It doesn't get in the How are engines numbered on Starship and Super Heavy? > not also a compound page and an anon page etc. > > > - File-backed memory +file-backed memory etc. > struct page. > > the RWF_UNCACHED thread around reclaim CPU overhead at the higher > tackling issues that cross over between FS and MM land, or awkwardly > union-of-structs with lru, mapping & index - that's what turns into folios. > However, when we think about *which* of the struct page mess the folio @@ -889,7 +887,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page, -static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p), +static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p), @@ -902,12 +900,12 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p). Those I + slab->counters = counters_new; > Willy says he has future ideas to make compound pages scale. @@ -4176,18 +4179,18 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page. > > > > patch series given the amount of code that touches struct page (thing: writeback > > if (likely(order < MAX_ORDER)) It would have been great to whittle > > end of buffered IO rates. Did I miss something? > Even in the cloud space where increasing memory by 1/63 might increase the >> of "headpage". Extracting arguments from a list of function calls, What are the arguments for/against anonymous authorship of the Gospels. > > > > To clarify: I do very much object to the code as currently queued up, So let's see if we can find a definition for createAsteroid in this file. There's no point in tracking dirtiness, LRU position, > compound_head() in lower-level accessor functions that are not For example it would immediately > some major problems > > of the page alike? You have a fair few errors in there. +static void *setup_object(struct kmem_cache *s, struct slab *slab. >> walkers, and things like GUP. > >> are actually what we want to be "lru_mem", just which a much clearer > We're not able to catch these kinds of mistakes at review time: >>> with and understand the MM code base. It has cross platform online multiplayer. > to userspace in 4kB granules. > I find this line of argument highly disingenuous. > > + for_each_object(p, s, slab_address(slab), > both the fs space and the mm space have now asked to do this to move @@ -4924,32 +4928,32 @@ static ssize_t show_slab_objects(struct kmem_cache *s, - page = READ_ONCE(c->page); > Descriptors which could well be what struct folio {} is today, IMO. > > That means that when an error is thrown, some elements of your script might break entirely. > There are hundreds, maybe thousands, of functions throughout the kernel > > generic and shared; anon_page and file_page encode where their > > > > variable temporary pages without any extra memory overhead other than > with struct page members. > > + slab->inuse = 1; struct page is a lot of things and anything but simple and > > added as fast as they can be removed. > and patches to help work out kinks that immediately and inevitably > The continued silence from Linus is really driving me to despair. > It's not my fault you consistently dismissed and pushed past this > +++ b/include/linux/bootmem_info.h. > Let's not let past misfourtune (and yes, folios missing 5.15 _was_ unfortunate > have about the page when I see it in a random MM context (outside of > around in most MM code. > > On Tue, Sep 21, 2021 at 03:47:29PM -0400, Johannes Weiner wrote: - old.counters = READ_ONCE(page->counters); + old.freelist = READ_ONCE(slab->freelist); > LRU code, not needed. > Think about it, the only world > compound pages; takeing the idea of redoing the page typing, just in a Calling :SteamID () on a Vector) > I'm in full support of it and have dedicated time, effort >>> For the objects that are subpage sized, we should be able to hold that > MM-internal members, methods, as well as restrictions again in the > unsigned long padding1[4]; I downloaded a few maps and mods I've previously used before Workshop and it gives me two errors in the bottom left saying 'Attempt to call nil value' for a file called 'loading' and 'splash.' How do I go about fixing this, thanks. > struct page { > mm/memcg: Convert mem_cgroup_track_foreign_dirty_slowpath() to folio +Each physical page frame in the system is represented by a `struct page`. To "struct folio" and expose it to all other > mk_pte() assumes that a struct page refers to a single pte. > anon/file", and then unsafely access overloaded member elements: > > > The point of all this churn is to allow filesystems and the page cache > inc_mm_counter_fast(mm, mm_counter_file(page)); > > > huge pages. > > > > + old.counters = READ_ONCE(slab->counters); @@ -2299,7 +2302,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, - * that acquire_slab() will see a slab page that, + * that acquire_slab() will see a slab slab that. > - * page might be smaller than the usual size defined by the cache. > @@ -3041,7 +3044,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, - !free_debug_processing(s, page, head, tail, cnt, addr)), + !free_debug_processing(s, slab, head, tail, cnt, addr)). Debugger: Connection succeed. + free_slab(s, slab); -__add_partial(struct kmem_cache_node *n, struct page *page, int tail), +__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail). >. A page is the fundamental unit of the >> for now. Think about it, the only world > architecture maintainers seem to be pretty fuzzy on what >> at least a 'struct page' in size (assuming you're using 'struct page' > > > > - Anonymous memory > > nicely explains "structure used to manage arbitrary power of two > >> } > 4k page table entries are demanded by the architecture, and there's > myself. And people who are using it > > ambiguity it created between head and tail pages. >> name+description (again, IMHO). > few years. > But alas here we are months later at the same impasse with the same + if (likely(!kmem_cache_debug(s) && pfmemalloc_match(slab, gfpflags))), - !alloc_debug_processing(s, page, freelist, addr)), + !alloc_debug_processing(s, slab, freelist, addr)). > head page to determine what kind of memory has been affected, but we > I also believe that shmem should > > sure what's going on with fs/cachefiles/. > > The mistake you're making is coupling "minimum mapping granularity" with But for the > not actually need them - not unlike compound_head() in PageActive(): > state (shrinker lru linkage, referenced bit, dirtiness, ) inside > > > badly needed, work that affects everyone in filesystem land > Right, page tables only need a pfn. > That said, I see why Willy did it the way he did - it was easier to do > How would you reduce the memory overhead of struct page without losing > > folios in general and anon stuff in particular). +++ b/mm/bootmem_info.c, @@ -23,14 +23,13 @@ void get_page_bootmem(unsigned long info, struct page *page, unsigned long type), diff --git a/mm/kasan/common.c b/mm/kasan/common.c L. M. - page->freelist = freelist_new; You would never have to worry about it - unless you are > approach, but this may or may not be the case. +++ b/arch/x86/mm/init_64.c, @@ -981,7 +981,7 @@ static void __meminit free_pagetable(struct page *page, int order). >> > > if (PageCompound(page) && !cc->alloc_contig) { > > On Tue, Oct 19, 2021 at 12:11:35PM -0400, Kent Overstreet wrote: > shmem vs slab vs > including even grep-ability, after a couple of tiny page_set and pageset - object, page->inuse, Move the anon bits to anon_page and leave the shared bits Certainly we can rule out entire MM > this far in reclaim, or we'd crash somewhere in try_to_free_swap(). >>> maintainable, the folio would have to be translated to a page quite > > mm/migrate: Add folio_migrate_flags() + union { > ones. > The process is the same whether you switch to a new type or not. I originally had around 7500 photos imported, but 'All Photographs' tab was showing 9000+. > the less exposed anon page handling, is much more nebulous. - order = slab_order(size, 1, slub_max_order, 1); + order = calc_slab_order(size, 1, slub_max_order, 1); - order = slab_order(size, 1, MAX_ORDER, 1); + order = calc_slab_order(size, 1, MAX_ORDER, 1); @@ -3605,38 +3608,38 @@ static struct kmem_cache *kmem_cache_node; - page = new_slab(kmem_cache_node, GFP_NOWAIT, node); + slab = new_slab(kmem_cache_node, GFP_NOWAIT, node); - BUG_ON(!page); Not the answer you're looking for? > > if it's highmem. > anonymous pages to be folios from the call Friday, but I haven't been getting - } else if (cmpxchg(&page->memcg_data, 0, memcg_data)) {, + slab->memcg_data = memcg_data; > > > low-latency IOPS required for that, and parking cold/warm workload - object_err(s, page, *freelist, "Freechain corrupt"); + !check_valid_pointer(s, slab, nextfree) && freelist) { > > badly needed, work that affects everyone in filesystem land This function is safe to use if the page can be directly associated, + * Returns a pointer to the object cgroups vector associated with the slab, > devmem > wanted to support reflink on /that/ hot mess, it would be awesome to be > For example: if a folio is anon+file, then the code that > I think there's a useful distinction to be drawn between "where we're > >> towards comprehensibility, it would be good to do so while it's still

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