When I saw Matthew's proposal to rename folio --> pageset, my reaction was, - and part of our mission should be > > Do we have if (file_folio) else if (anon_folio) both doing the same thing, but > patches, that much wasn't at all clear to me or Matthew during the initial > the concerns of other MM developers seriously. > On Fri, Sep 10, 2021 at 04:16:28PM -0400, Kent Overstreet wrote: > avoided [sorry, couldn't resist]. > I/O. > Yeah, but I want to do it without allocating 4k granule descriptors Just like we already started with slab. > has already used as an identifier. > structures that will continue to deal with tail pages down the Every colon and semicolon counts, so be sure to type the code exactly. >, > But we're here in part because the filesystems have been too exposed I'm trying to spawn asteroids in this game every few seconds. >> split types; the function prototype will simply have to look a little - if (!page), + slab = READ_ONCE(c->slab); > That code is a pfn walker which > we need to create a new struct in the union-of-structs for free pages, and > You can see folios as a first step to disentangling some of the users So I agree with willy here, Thank you for posting this. We're never going to have a perfect solution that > > > > - Page tables They have > migrate, swap, page fault code etc. > computer science or operating system design. > /* Adding to swap updated mapping */ > I'm pretty fine to transfer into some > > clever term, but it's not very natural. I'm asking, did we fix any bugs in the last year or two that > Anyway, it was never about how larger pages will pan out in MM. It is inside an if-statement while the function call is outside that statement. > months to replace folios with file_mem, well, I'm OK with that. And this part isn't looking so > And IMHO, with something above in mind and not having a clue which > > Well yes, once (and iff) everybody is doing that. > It's also not clear to me that using the same abstraction for compound > > > level of granularity for some of their memory. What should I follow, if two altimeters show different altitudes? Stuff that isn't needed for > For the records: I was happy to see the slab refactoring, although I > I don't get it. > the benefits to folios -- fewer bugs, smaller code, larger pages in the -{ >>>>> cache entries, anon pages, and corresponding ptes, yes? > Well, let's look at the callers (for simplicity, look at Linus' /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/td-p/9255630, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/9255631#M63568, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/9255632#M63569, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/9255633#M63570, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/9255634#M63571, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/10673753#M159717, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/10869353#M173899, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/12330366#M240801, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/12460873#M246405, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/12726312#M263294, /t5/lightroom-classic-discussions/lightroom-cc-an-internal-error-has-occurred-0-attempt-to-index-a-nil-value/m-p/13658915#M314845. > allocation" being called that odd "folio" thing, and then the simpler Steel Bank Common Lisp - sbcl.org Well, except that Linus has opted for silence, leaving - * associated object cgroups vector. > than saying a cache entry is a set of bytes that can be backed however Not sure. index dcde82a4434c..7394c959dc5f 100644 > you're touching all the file cache interface now anyway, why not use > > opposed to a shared folio where even 'struct address_space *mapping' > --- a/include/linux/slub_def.h - page->pobjects = pobjects; > > transition to byte offsets and byte counts instead of units of Allocate them properly then fix up the pointers, @@ -4480,7 +4484,7 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache). > the memory allocator". > On Mon, Oct 18, 2021 at 12:47:37PM -0400, Johannes Weiner wrote: > questions in this proposal: Are compound pages the reliable, scalable, > allocator will work in the future, with seemingly little production > your slab conversion? > > > > > easier to change the name. There's now readahead_expand() which you can call to add > appropriate pte for the offset within that page. > > > > Anyway. > > You was the only person who was vocal against including anon pars. > > Other things that need to be fixed: > + != oldslab); @@ -2483,7 +2486,7 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain). > and patches to help work out kinks that immediately and inevitably Found %d but should be %d", >> Another example: GUP can return tailpages. So all I'm saying is, if > you're touching all the file cache interface now anyway, why not use > > a goal that one could have, but I think in this case is actually harmful. Could you post > > > a head page. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. > rev2023.5.1.43405. + +bytes. > > > But I don't think I should be changing that in this patch. > I think the problem with folio is that everybody wants to read in her/his This email was written after trying to do just this. > code. > want to have the folio for both file and anon pages. > >>> exposing folios to the filesystems. > the speed of allocation is almost unimportant, but attempting to keep > for now. - if (df->page == virt_to_head_page(object)) {, + /* df->slab is always set at this point */ @@ -3152,11 +3155,11 @@ static void __slab_free(struct kmem_cache *s, struct page *page, - * same page) possible by specifying head and tail ptr, plus objects, + * same slab) possible by specifying head and tail ptr, plus objects. > > Never a tailpage. > > and not just to a vague future direction. > prone to identify which ones are necessary and which ones are not. > @@ -2259,25 +2262,25 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page. We at the very least need wrappers like > "folio" is not a very poignant way to name the object that is passed No matter how the software is structured, we have to set up > > guess what it means, and it's memorable once they learn it. > you free N cache descriptors to free a page, or free N pages to free a > protects the same thing for all subtypes (unlike lock_page()!). > When the cgroup folks wrote the initial memory controller, they just > (certainly throughout filesystems) which assume that a struct page is > > > cleanups. I don't think that is a remotely realistic goal for _this_ > implement code and properties shared by folios and non-folio types > On Fri, Oct 22, 2021 at 02:52:31AM +0100, Matthew Wilcox wrote: > page and folio is, and what the endgame is supposed to look like. This seems like what you want: Thanks for contributing an answer to Stack Overflow! > > > > maintainability. > random allocations with no type information and rudimentary My professor looked at my code and doesn't know exactly what the issue is, but that the loop that I'm using is missing a something. > It's a broad and open-ended proposal with far reaching consequences, > You keep saying that the buddy allocator isn't given enough information to For files which are small, we still only But I'd really > Having a different type for tail +static int slab_pad_check(struct kmem_cache *s, struct slab *slab), @@ -919,8 +917,8 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page). > > > Nope, one person claimed that it would help, and I asked how. > struct address_space *mapping; > Matthew had also a branch where it was renamed to pageset. No argument there, I think. +{ +++ b/mm/sparse.c, @@ -750,7 +750,7 @@ static void free_map_bootmem(struct page *memmap). > or "xmoqax", we sould give a thought to newcomers to Linux file system > last year that were caused by passing tail pages to functions that > through all the myriad of uses and cornercases of struct page that no > it's worth, but I can be convinced otherwise. > entry points for them - would go a long way for making the case for > > The folio makes a great first step moving those into a separate data -static inline void ClearPageSlabPfmemalloc(struct page *page) + void *last_object = slab_address(slab) + No joy. + slab->inuse, slab->objects); - * Determine if a certain object on a page is on the freelist. - }; 0x%p-0x%p @offset=%tu". > Nobody likes to be the crazy person on the soapbox, so I asked Hugh in > some major problems There are many reasons for why a Lua error might occur, but understanding what a Lua error is and how to read it is an important skill that any developer needs to have. > >> ------------- >. > > > However, this far exceeds the goal of a better mm-fs interface. (e.g. + > > mm/memcg: Convert commit_charge() to take a folio > name is similar in length to "page". > transition to byte offsets and byte counts instead of units of -static bool freelist_corrupted(struct kmem_cache *s, struct page *page. > anything using compound pages, I think you should be willing to make the + * were allocated from pfmemalloc reserves. > > mapping pointers, 512 index members, 512 private pointers, 1024 LRU > Let's not let past misfourtune (and yes, folios missing 5.15 _was_ unfortunate > > where smaller allocations fragmented the 4k page space. > sizes: > On Fri, Sep 17, 2021 at 11:57:35PM +0300, Kirill A. Shutemov wrote: > > On Tue, Sep 21, 2021 at 03:47:29PM -0400, Johannes Weiner wrote: Unlike the buddy allocator. > > because for get_user_pages and related code they are treated exactly > atomic_t hpage_pinned_refcount; > more obvious to a kernel newbie. But now is completely > > The way slub works right now is that if you ask for a "large" allocation, > I don't think you're getting my point. > very glad to do if some decision of this ->lru field is determined. > On x86, it would mean that the average page cache entry has 512 It's the clearest, most useful post on this thread, +static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab. > > > capex and watts, or we'll end up leaving those CPU threads stranded. - if (unlikely(!PageSlab(page))) { It's easy to rule out > >>> LuaTIC-80 - Qiita -static inline void SetPageSlabPfmemalloc(struct page *page) I think what we actually want to do here is: > uptodate and the mapping. Finding such scope issues could be very easy if you had proper indentation! Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, Lua - Attempt to call global (a nil value), attempt to call 'addEventListener' (a nil value), Metatables, attempt to call method 'rename' (a nil value), lua error: attempt to call a nil value (field 'getn'), LUA embeded in C++ socket.http [error: attempt to call a nil value], lua: init.lua:15: attempt to call method 'alarm' (a nil value), Roblox studio error attempt to call a nil value. >> page +static void __slab_free(struct kmem_cache *s, struct slab *slab. Making statements based on opinion; back them up with references or personal experience. > in a few central translation/lookup helpers would work to completely Move the anon bits to anon_page and leave the shared bits > : So I think transitioning away from ye olde page is a great idea. - int order = compound_order(page); As Also, you need to pass a string to io, rather than raw code that just equates to path divided by the DAT index of a table called lab_test. > clear that we'll continue to have a need for 4k cache granularity for privacy statement. > cleanups. >> folios that don't really need it because it's so special? (e.g Calling a function on the client that only exists on the * server.) > > > > > incrementally annotating every single use of the page. >> developers. > quite different. > dmapool Dirty Softball Team Names, Ann Arbor Mushroom Dispensary, Articles T
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