Hi Christoph, On Thu, 4 Jan 2007, Christoph Lameter wrote: > Good idea if you can make it so that it is clean. There is some > additional processing in cache_grow() that would have to be taken into > account.
Something like this (totally untested) patch? diff --git a/mm/slab.c b/mm/slab.c index 0d4e574..48fa397 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -1608,8 +1608,19 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) { struct page *page; int nr_pages; + void *ret; int i; + /* + * The test for missing atomic flag is performed here, rather than + * the more obvious place, simply to reduce the critical path length + * in kmem_cache_alloc(). If a caller is seriously mis-behaving they + * will eventually be caught here (where it matters). + */ + kmem_flagcheck(cachep, flags); + if (flags & __GFP_WAIT) + local_irq_enable(); + #ifndef CONFIG_MMU /* * Nommu uses slab's for process anonymous memory allocations, and thus @@ -1621,8 +1632,10 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) flags |= cachep->gfpflags; page = alloc_pages_node(nodeid, flags, cachep->gfporder); - if (!page) - return NULL; + if (!page) { + ret = NULL; + goto out; + } nr_pages = (1 << cachep->gfporder); if (cachep->flags & SLAB_RECLAIM_ACCOUNT) @@ -1633,7 +1646,12 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) NR_SLAB_UNRECLAIMABLE, nr_pages); for (i = 0; i < nr_pages; i++) __SetPageSlab(page + i); - return page_address(page); + + ret = page_address(page); + out: + if (flags & __GFP_WAIT) + local_irq_disable(); + return ret; } /* @@ -2714,7 +2732,7 @@ static void slab_map_pages(struct kmem_cache *cache, struct slab *slab, * Grow (by 1) the number of slabs within a cache. This is called by * kmem_cache_alloc() when there are no active objs left in a cache. */ -static int cache_grow(struct kmem_cache *cachep, +static int __cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid, void *objp) { struct slab *slabp; @@ -2754,39 +2772,17 @@ static int cache_grow(struct kmem_cache *cachep, offset *= cachep->colour_off; - if (local_flags & __GFP_WAIT) - local_irq_enable(); - - /* - * The test for missing atomic flag is performed here, rather than - * the more obvious place, simply to reduce the critical path length - * in kmem_cache_alloc(). If a caller is seriously mis-behaving they - * will eventually be caught here (where it matters). - */ - kmem_flagcheck(cachep, flags); - - /* - * Get mem for the objs. Attempt to allocate a physical page from - * 'nodeid'. - */ - if (!objp) - objp = kmem_getpages(cachep, flags, nodeid); - if (!objp) - goto failed; - /* Get slab management. */ slabp = alloc_slabmgmt(cachep, objp, offset, local_flags & ~GFP_THISNODE, nodeid); if (!slabp) - goto opps1; + return 0; slabp->nodeid = nodeid; slab_map_pages(cachep, slabp, objp); cache_init_objs(cachep, slabp, ctor_flags); - if (local_flags & __GFP_WAIT) - local_irq_disable(); check_irq_off(); spin_lock(&l3->list_lock); @@ -2796,12 +2792,28 @@ static int cache_grow(struct kmem_cache *cachep, l3->free_objects += cachep->num; spin_unlock(&l3->list_lock); return 1; -opps1: - kmem_freepages(cachep, objp); -failed: - if (local_flags & __GFP_WAIT) - local_irq_disable(); - return 0; +} + +static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid) +{ + void *objp; + int ret; + + if (flags & __GFP_NO_GROW) + return 0; + + /* + * Get mem for the objs. Attempt to allocate a physical page from + * 'nodeid'. + */ + objp = kmem_getpages(cachep, flags, nodeid); + if (!objp) + return 0; + + ret = __cache_grow(cachep, flags, nodeid, obj); + if (!ret) + kmem_freepages(cachep, objp); + return ret; } #if DEBUG @@ -3014,7 +3026,7 @@ alloc_done: if (unlikely(!ac->avail)) { int x; - x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL); + x = cache_grow(cachep, flags | GFP_THISNODE, node); /* cache_grow can reenable interrupts, then ac could change. */ ac = cpu_cache_get(cachep); @@ -3288,18 +3300,13 @@ retry: * We may trigger various forms of reclaim on the allowed * set and go into memory reserves if necessary. */ - if (local_flags & __GFP_WAIT) - local_irq_enable(); - kmem_flagcheck(cache, flags); obj = kmem_getpages(cache, flags, -1); - if (local_flags & __GFP_WAIT) - local_irq_disable(); if (obj) { /* * Insert into the appropriate per node queues */ nid = page_to_nid(virt_to_page(obj)); - if (cache_grow(cache, flags, nid, obj)) { + if (__cache_grow(cache, flags, nid, obj)) { obj = ____cache_alloc_node(cache, flags | GFP_THISNODE, nid); if (!obj) @@ -3370,7 +3377,7 @@ retry: must_grow: spin_unlock(&l3->list_lock); - x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL); + x = cache_grow(cachep, flags | GFP_THISNODE, nodeid); if (x) goto retry; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/