Messages in this thread | | | Date | Tue, 22 Sep 2015 12:18:58 +0200 | Subject | Re: [PATCH 1/2] zbud: allow PAGE_SIZE allocations | From | Vitaly Wool <> |
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Hi Dan,
On Mon, Sep 21, 2015 at 6:17 PM, Dan Streetman <ddstreet@ieee.org> wrote: > Please make sure to cc Seth also, he's the owner of zbud.
Sure :)
<snip> >> @@ -514,8 +552,17 @@ int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries) >> return -EINVAL; >> } >> for (i = 0; i < retries; i++) { >> - zhdr = list_tail_entry(&pool->lru, struct zbud_header, lru); >> - list_del(&zhdr->lru); >> + page = list_tail_entry(&pool->lru, struct page, lru); >> + zhdr = page_address(page); >> + list_del(&page->lru); >> + /* Uncompressed zbud page? just run eviction and free it */ >> + if (page->flags & PG_uncompressed) { >> + page->flags &= ~PG_uncompressed; >> + spin_unlock(&pool->lock); >> + pool->ops->evict(pool, encode_handle(zhdr, FULL)); >> + __free_page(page); >> + return 0; > > again, don't be redundant. change the function to handle full-sized > pages, don't repeat the function in an if() block for a special case.
Well, this case is a little tricky. How to process a zbud page in zbud_reclaim_page() is defined basing on the assumption there is a zhdr at the beginning of the page. What can be done here IMV is either of the following: * add a constant magic number to zhdr and check for it, if the check fails, it is a type FULL page * add a CRC field to zhdr, if CRC check over assumed zhdr fails, it is a type FULL page * use a field from struct page to indicate its type
The last option still looks better to me.
~vitaly
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