Date: Sat, 31 Dec 2022 02:47:56 GMT From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 55038a6306a5 - main - LinuxKPI: add simplified vesion of page_frag_cache Message-ID: <202212310247.2BV2luJE035973@gitrepo.freebsd.org>
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The branch main has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=55038a6306a570c9f2df89f5ad076de0f7d98152 commit 55038a6306a570c9f2df89f5ad076de0f7d98152 Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2022-12-03 00:33:34 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2022-12-31 02:45:44 +0000 LinuxKPI: add simplified vesion of page_frag_cache For the moment and the currently only consumer (mt76) add a simplified version of the page_frag_cache. We will only accept fragement sizes up to 1 PAGE_SIZE (KASSERT) and we will always return a full page. Should we add more consumers or small (or large) objects would become a problem we can always add a more elaborate version. Discussed with: markj Reviewed by: markj (,hselasky commented as well) MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D37595 --- sys/compat/linuxkpi/common/include/linux/gfp.h | 29 +++++++++++++++++ sys/compat/linuxkpi/common/src/linux_page.c | 45 ++++++++++++++++++++++++++ 2 files changed, 74 insertions(+) diff --git a/sys/compat/linuxkpi/common/include/linux/gfp.h b/sys/compat/linuxkpi/common/include/linux/gfp.h index 63b23b4b637e..a2930b44b0c4 100644 --- a/sys/compat/linuxkpi/common/include/linux/gfp.h +++ b/sys/compat/linuxkpi/common/include/linux/gfp.h @@ -81,6 +81,11 @@ CTASSERT((__GFP_DMA32 & GFP_NATIVE_MASK) == 0); CTASSERT((__GFP_BITS_MASK & GFP_NATIVE_MASK) == GFP_NATIVE_MASK); +struct page_frag_cache { + void *va; + int pagecnt_bias; +}; + /* * Resolve a page into a virtual address: * @@ -95,6 +100,9 @@ extern void *linux_page_address(struct page *); */ extern vm_page_t linux_alloc_pages(gfp_t flags, unsigned int order); extern void linux_free_pages(vm_page_t page, unsigned int order); +void *linuxkpi_page_frag_alloc(struct page_frag_cache *, size_t, gfp_t); +void linuxkpi_page_frag_free(void *); +void linuxkpi__page_frag_cache_drain(struct page *, size_t); static inline struct page * alloc_page(gfp_t flags) @@ -176,6 +184,27 @@ free_page(uintptr_t addr) linux_free_kmem(addr, 0); } +static inline void * +page_frag_alloc(struct page_frag_cache *pfc, size_t fragsz, gfp_t gfp) +{ + + return (linuxkpi_page_frag_alloc(pfc, fragsz, gfp)); +} + +static inline void +page_frag_free(void *addr) +{ + + linuxkpi_page_frag_free(addr); +} + +static inline void +__page_frag_cache_drain(struct page *page, size_t count) +{ + + linuxkpi__page_frag_cache_drain(page, count); +} + static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags) { diff --git a/sys/compat/linuxkpi/common/src/linux_page.c b/sys/compat/linuxkpi/common/src/linux_page.c index 26b0ed649372..2bbe8f502cba 100644 --- a/sys/compat/linuxkpi/common/src/linux_page.c +++ b/sys/compat/linuxkpi/common/src/linux_page.c @@ -429,3 +429,48 @@ lkpi_arch_phys_wc_del(int reg) free(mrdesc, M_LKMTRR); #endif } + +/* + * This is a highly simplified version of the Linux page_frag_cache. + * We only support up-to 1 single page as fragment size and we will + * always return a full page. This may be wasteful on small objects + * but the only known consumer (mt76) is either asking for a half-page + * or a full page. If this was to become a problem we can implement + * a more elaborate version. + */ +void * +linuxkpi_page_frag_alloc(struct page_frag_cache *pfc, + size_t fragsz, gfp_t gfp) +{ + vm_page_t pages; + + if (fragsz == 0) + return (NULL); + + KASSERT(fragsz <= PAGE_SIZE, ("%s: fragsz %zu > PAGE_SIZE not yet " + "supported", __func__, fragsz)); + + pages = alloc_pages(gfp, flsl(howmany(fragsz, PAGE_SIZE) - 1)); + pfc->va = linux_page_address(pages); + + /* Passed in as "count" to __page_frag_cache_drain(). Unused by us. */ + pfc->pagecnt_bias = 0; + + return (pfc->va); +} + +void +linuxkpi_page_frag_free(void *addr) +{ + vm_page_t page; + + page = PHYS_TO_VM_PAGE(vtophys(addr)); + linux_free_pages(page, 0); +} + +void +linuxkpi__page_frag_cache_drain(struct page *page, size_t count __unused) +{ + + linux_free_pages(page, 0); +}
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