git: 4ca9190251bb - main - LinuxKPI: alloc_pages(): Don't reclaim on __GFP_NORETRY

The branch main has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=4ca9190251bbd00c928a3cba54712c3ec25e9e26

commit 4ca9190251bbd00c928a3cba54712c3ec25e9e26
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2025-07-07 12:27:48 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2025-07-13 06:41:19 +0000

    LinuxKPI: alloc_pages(): Don't reclaim on __GFP_NORETRY
    
    Pass VM_ALLOC_NORECLAIM to vm_page_alloc_noobj_contig() so that it
    avoids reclaiming (currently, calling vm_reserv_reclaim_contig()).
    
    According to Linux's documentation, __GFP_NORETRY should not cause any
    "disruptive reclaim".  alloc_pages() is called a lot from the amdgpu DRM
    driver via ttm_pool_alloc(), which tries to allocate pages of the
    highest order first and fallback to lower order pages (as allocating
    contiguous physical pages is in fact not a requirement).  This process
    relies on failing fast, as requested by __GFP_NORETRY.  See also related
    commit 718d1928f874 ("LinuxKPI: make linux_alloc_pages() honor
    __GFP_NORETRY").
    
    Reviewed by:    jeffpc_josefsipek.net, bz
    MFC after:      10 days
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D51246
---
 sys/compat/linuxkpi/common/src/linux_page.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/compat/linuxkpi/common/src/linux_page.c b/sys/compat/linuxkpi/common/src/linux_page.c
index ebb92eacbf9a..628af17df853 100644
--- a/sys/compat/linuxkpi/common/src/linux_page.c
+++ b/sys/compat/linuxkpi/common/src/linux_page.c
@@ -106,6 +106,7 @@ linux_alloc_pages(gfp_t flags, unsigned int order)
 
 		if ((flags & M_ZERO) != 0)
 			req |= VM_ALLOC_ZERO;
+
 		if (order == 0 && (flags & GFP_DMA32) == 0) {
 			page = vm_page_alloc_noobj(req);
 			if (page == NULL)
@@ -113,6 +114,10 @@ linux_alloc_pages(gfp_t flags, unsigned int order)
 		} else {
 			vm_paddr_t pmax = (flags & GFP_DMA32) ?
 			    BUS_SPACE_MAXADDR_32BIT : BUS_SPACE_MAXADDR;
+
+			if ((flags & __GFP_NORETRY) != 0)
+				req |= VM_ALLOC_NORECLAIM;
+
 		retry:
 			page = vm_page_alloc_noobj_contig(req, npages, 0, pmax,
 			    PAGE_SIZE, 0, VM_MEMATTR_DEFAULT);